US20050002419A1 - Apparatus and method for intelligent routing of data between a remote device and a host system - Google Patents

Abstract

An apparatus and method is provided for transparent communication between a remote or mobile device and a fixed communication host network. The apparatus and method may include a remote network controller that logically resides between the host network and the existing infrastructure(s) that are used to provide communications network contact with one or more remote devices. The remote network controller is connected to the host communication network as a protocol-appropriate communications controller so that remote devices are indistinguishable to the host network from the locally-attached devices. Each remote device may be provided with an asynchronous serial data interface to communicate with a mobile data controller. The mobile data controller, in combination with the remote network controller, provides end-to-end data communication such that incompatible protocols are transparent to the remote device and host communication network. A router may be provided which selects a communications network in accordance with user configured parameters. The router communicates over a plurality of incompatible networks and is capable of using a variety of different protocols. Switching between the plurality of incompatible networks is transparent to the remote device and host communication network.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a Continuation of application Ser. No. 10/164,581, filed Jun. 10, 2002, which is a Continuation of application Ser. No. 08/932,532, filed Sep. 17, 1997 (now U.S. Pat. No. 6,418,324), which is a Continuation-In-Part of application Ser. No. 08/456,860, filed Jun. 1, 1995 (now U.S. Pat. No. 5,717,737), the contents of which are expressly incorporated by reference herein in their entireties.
BACKGROUND OF THE INVENTION
• 1. Field of Invention
• The present invention relates to the transportation of data through dissimilar communications media. More particularly, the present invention relates to an apparatus and method for transporting data between a remote mobile or fixed terminal device and a host system over multiple, dissimilar communications media. The communications media over which the data is transported include wireless data links, wired data links or a combination of wireless and wired data links which are selected based upon a set of preference metrics.
• 2. Background Information
• The ability to transport data between mobile and/or fixed terminal devices and host computer systems have been generally available for many years. Networks designed to transport this data currently exist in a wide variety of wireless and wired network architectures. Both apparatus and method exists for transporting data through multiple, similar media types as well as the automatic selection of alternate communication paths based upon a plurality of preference metrics.
• Often, when multiple networks are available from a common location such as a vehicle, great benefit may be derived by allowing uniform communications through all available networks. Certain networks may perform better for bulk data transfers where another may perform interactive messaging in an optimal fashion. One network may be preferable because of its low cost but an alternate, more expensive network may be acceptable as a backup if the low-cost network is unavailable.
• Other examples include U.S. Pat. No. 5,412,375, to WOOD, which discloses a system for selecting one of a plurality of interfaces to a single wireless communications system in accordance with the capabilities of a subscriber unit and the capabilities of a base unit. A list of air interface capabilities of the subscriber unit and the base unit are compared by a controller to determine a compatible interface. As disclosed in WOOD, the plurality of air interfaces include Analog Mobile Phone System (AMPS), Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). While the WOOD system does select from one of a plurality of interfaces which may be applicable for data communication, the routing decision is based on the capabilities of the endpoints rather than the preference metrics of the transporting networks. The endpoint devices, in this case, must be aware of the peculiarities of the wireless environment.
• U.S. Pat. No. 5,420,574, to ERICKSON et al., discloses a subscriber unit attached to a trunked mobile radio having a data input. The mobile radio communicates both voice and data message formats over a wireless network to a base station via channels that are allocated by a trunked data controller which is connected to a host network. Channel states and communication parameters are set in accordance with the type of information (e.g., voice or data) that is being transmitted or received. While the ERICKSON et al. system dynamically switches between incompatible message formats without the intervention of the endpoint devices, only a single data path is provided. In addition, the incompatibility of the two alternate paths arises from a difference in message formats rather than the use of independent, incompatible networks.
• Further, the transportation of data through alternate, incompatible communications media is a problem that does not have a uniform solution in the art. This problem is exacerbated in wireless communication networks where protocols, timing and other incompatibilities render an otherwise acceptable level of service inadequate. Attempts to provide data links through incompatible networks have suffered from the same obstacles that hindered data communications prior to open standards becoming widely accepted, i.e., proprietary protocols visible to the endpoint terminal devices make the devices inflexible and expensive and the interoperation of similar devices with incompatible networking components is difficult and complex.
• Networks may be interconnected by routers which operate at the network level and convey messages between compatible networks. Routers make logical decisions about the pathway through which data is to be directed in the networks based upon a variety of preference metrics. A router is generally implemented as an autonomous device with multiple connections to the networks through which data is to be routed. Routers operate at the network layer and can recognize and manage protocols and multiple connections to networks. Routers usually operate in accordance with the address provided by the particular protocol of the network, and normally provide routing between and through networks utilizing the same network protocol and can route between networks that use different data-link layers, such as Ethernet, Token-Ring, Serial PPP, etc. Another type of router includes two routers loosely-coupled through a protocol-neutral data-link, where the linked routers are considered as a single “virtual” router.
• Dissimilar networks may be connected by gateways which are devices that interconnect two or more dissimilar networks. A gateway differs from a router in that the endpoint terminal devices may implement a dissimilar or incompatible protocols. Gateways often perform specific protocol conversions at the layers above the network layer to move data from one type of network to another. In this regard, the Open Systems Interconnection (OSI) model includes seven “layers” to provide communications between heterogeneous (i.e., incompatible) systems. The layers, from lowest to highest, are: the physical layer, the data link layer, the network layer, the transport layer, the session layer, the presentation layer, and the application layer. Each of the layers performs a specific task in transporting data between two or more entities. Such a layered structure is shown in The TCP/IP Companion, by Martin R. Arick, Wiley-QED, pp. 18-19.
• U.S. patent application Ser. No. 08/456,860, to DOVIAK et al., for example, discloses a system in which a distant mobile or fixed terminal device transports data through a plurality of wireless network to an endpoint which may or may not implement the same network protocol as the distant device. However, while the DOVIAK et al. system is capable transmitting data over a plurality of dissimilar wireless communications networks, the system does not automatically transmit data through differing ones of a plurality of dissimilar networks in accordance with preference metrics to reach the data-link endpoints. Thus, the system does not automatically provide redundant or alternate pathways through which data may be delivered.
• U.S. Pat. No. 5,537,220 to EZUMI et al., discloses a portable facsimile apparatus provided with a capability to communicate over a plurality of communications lines. As disclosed in EZUMI et al., the facsimile machine may communicate over telephone lines or a mobile communication unit. A NCU (controller) is provided within the facsimile machine to discriminate whether the facsimile machine is connected to the telephone line or to the mobile communication unit. The NCU functions to adjust the data rate, and transmitting and receiving signal levels based on which communication system it is communicating. Although this concept may be extended to a generic protocol-neutral data networking environment, the EZUMI et al. system provides for the selection of only one single path to the exclusion of other, possible viable path based solely on which link is plugged into the NCU. Further, the EZUM et al. system does not switch communication paths within the boundaries of a communication session thereby further limiting its usefulness in a connectionless, packet data environment such as a TCP/IP network.
• U.S. Pat. No. 5,602,843, to GRAY, discloses a PBX-based integrated telecommunications system having a wired subsystem connected to wired terminals, and a wireless system for connecting to mobile terminals. A controller is provided which manages base stations and communicates to wireless handsets. When communicating to a handset, the controller determines which base station is in communication with the handset and directs the base station to send packet-based information to that handset. A separate PBX controller is provided to communicate with the wired terminals. The PBX controller includes a proximity sensor to detect wireless handsets such that when a handset is detected in proximity to a wired terminal, messages are forwarded to the wired terminal rather than the wireless handset. While the GRAY system dynamically selects the route to a terminal device based upon a preference metric (wireless proximity), the alternate routing technique does not address transporting data between the same two endpoints. In addition, GRAY provides no means to provide alternate path routing for a terminal device through either the wireless or wired handsets.
• U.S. Pat. No. 5,452,471, to LEOPOLD et al., discloses a communication system having a primary and one or more subordinate communication systems. In the illustrated embodiment, the primary communication system is a satellite-base communication system having the widest area of coverage. Each of the satellites within the system defines a cell area which moves as the orbiting satellites move. The secondary and tertiary communications systems are disclosed as terrestrial based, stationary systems having base stations fixed near the surface of the earth (e.g., fixed to a building), where each subordinate system has an increasingly smaller region of coverage. The secondary and tertiary systems include a controller located at a monitoring location within each region. Each of the communications systems includes a link to a central office to enable communications over the public switched telephone network. The LEOPOLD et al. communication systems and mobile subscriber units operate within one frequency spectrum, however, the primary and secondary communication systems operate together by using orthogonal channels to prevent interference. In addition, when communicating with secondary systems, the mobile subscriber unit transmits at a relatively low power such that the primary system will not receive the transmission. The mobile subscriber unit is programmed to utilize the communication system having the smallest area of coverage such that if the subscriber unit has three communications systems available, the subscriber unit will utilize the tertiary communications system (i.e., the system having the smallest area of coverage) based on a designed assumption that the more subordinate the communication system is, the higher the capacity of the system. While the system of LEOPOLD et al. dynamically selects a route based upon a set of preference metrics such that the terminal endpoints are unaware of the routing selection, a common data-link protocol is required throughout all possible associated networks. In addition, the wireless frequencies employed must be derived from a continuous, compatible set of frequencies which prevents the device from selecting among inherently incompatible networks.
• Despite the teachings of these prior attempts, users of mobile or fixed wireless data communications are provided with systems of limited capacity and flexibility when routing data through more than one network. In addition, such systems require special hardware and/or software developed for and compatible with the networks, which may require additional training of support personnel and end-users. Further, users of wireless mobile data communication services are provided with only a limited ability to control costs associated with sending and receiving data to and from remote devices, and are limited in their hardware and software design implementations. In previous teachings, the candidate networks must be compatible with one another at either the network or the data-link level. Thus, routing data through inherently incompatible networks such as Cellular Digital Packet Data (CDPD) and Ericsson EDACS is not possible as these are incompatible at both the data-link and network levels. Moreover, known systems do not allow a customer to use existing RF wireless infrastructures, including existing hardware and software, with only minor modifications needed to transport data from a mobile device to a host computer network. In addition, past attempts do not permit wireless data communications in a manner that is transparent to the remote device. Further, prior systems do not provide the flexibility to users such that a plurality of different remote devices may communicate with the wired host network irrespective of the radio infrastructure and transmission protocol employed. Such features, without the above-noted drawbacks, would be highly desirable to provide flexibility and ease of use, and to give users of portable data devices greater control over their hardware and software design.
SUMMARY OF THE INVENTION
• In view of the foregoing, the present invention, through one or more of its various aspects, embodiments and/or specific features or sub-components thereof, is thus presented to bring about one or more objects and advantages, such as those specifically noted below.
• A general object of the present invention is to provide an apparatus and method for transporting data from a remote, wireless device to a wired network. Another object of the invention is to provide a remote device with an interface to present data to the wired network through RF wireless communication.
• More particularly, an object of the present invention is to provide an apparatus that resides between an existing wired communications network and an existing radio-frequency network to provide a wireless RF connection between a remote device and the wired network.
• Another object of the present invention is to provide an apparatus and method for a completely transparent data path between a remotely located device and an existing wired network using a wireless RF communications link without either the remote device, or the wired network being aware that a wireless RF communications link is being employed.
• Still another object of the present invention is to provide an apparatus and method for a completely transparent data path between a remotely located device and an existing wired network through a plurality of different wireless RF communications link protocols and a plurality of different wired networks protocols selected by the user.
• Still another object of the present invention is to provide an apparatus which functions as a protocol-appropriate communications controller and makes remote devices indistinguishable from locally attached devices to a wired network.
• According to one aspect of the present invention, an apparatus for transporting data between a remote device and a host communication network using a wireless communications link is provided. The apparatus comprises a mobile data controller connected to the remote device and the wireless communications link. The mobile data controller comprises a remote data conversion means for converting data to be transported between the remote device and the host communication network. The remote data conversion means converts the transported data between a remote device transmission format utilized by the remote device and a wireless link transmission format utilized by the wireless communications link.
• The apparatus also comprises a network interface means for interfacing the host communication network with the wireless communications link. The network interface means comprises a wireless link conversion means for converting the transported data between the wireless link transmission format and a network interface format utilized by the network interface means; and a host network conversion means for converting the transported data between the network interface format and a host network format utilized by the host communication network.
• The apparatus further comprises a means for transporting the transported data over the wireless communication in accordance with the wireless link transmission format, the wireless link transmission format and the host network format being incompatible. According to another aspect of the present invention, the network interface means comprises a remote network controller that logically resides on the host communication network and performs the functions of a network communication controller.
• According to another aspect of the present invention, the apparatus for transporting data further comprises a plurality of network interface means connected by a local network and a synchronization means for synchronizing the transfer of information between the network interface means, the information comprising routing tables and health and status information.
• According to the present invention a method of transporting data from a mobile device to a host network is provided. The remote device and a wireless communications link are connected by a mobile data controller, and the host communication network and the wireless communications link being interfaced by a network interface device.
• The method includes the steps of: converting, at the mobile data controller, data to be transported between the remote device and the host communication network, the converting step converting the transported data between a remote device transmission format utilized by the remote device and a wireless link transmission format utilized by the wireless communications link; transporting the transported data over the wireless communications link in accordance with the wireless link transmission format; receiving, at the network interface device, the transport data from the wireless communications link; converting, at the network interface device, the transported data between the wireless link transmission format and a network interface format utilized by the network interface device, the wireless link transmission format and the host network format being incompatible; further converting, at the network interface device, the transported data between the network interface format and a host network format utilized by the host communication network; and forwarding the transported data to the host communication network in accordance with the host network format.
• In a preferred embodiment, the transportation step further comprises determining wireless communications link selection criteria; dynamically selecting a wireless communications link from a plurality of incompatible wireless communications links in accordance with the selection criteria; and switching to the selected wireless communications link. Afterwards, the following steps are continuously repeated: dynamically selecting a next wireless communications link from the plurality of incompatible networks in accordance with the selection criteria; determining whether to switch wireless communications links; and switching to the next wireless communications link in response to a result of the determination.
• According to another aspect of the present invention, an apparatus for transporting data over a plurality of incompatible networks between a first device and a second device is provided. The apparatus comprises a system for determining network selection criteria. In addition, the apparatus comprises a selection system for dynamically selecting a network from the plurality of incompatible networks in accordance with the network selection criteria and a switching system for switching to the selected network to use for data transport.
• According to another aspect of the present invention, the apparatus transports data via a plurality of protocols over a plurality of incompatible networks in which the transportation of data is transparent to the first and second devices and to an end user. The protocols may include but are not limited to Internet Protocol (IP) and transparent protocol.
• According to another aspect of the present invention, the apparatus for transporting data further comprises a system interfacing protocolized data into a plurality of incompatible networks using different protocols.
• According to another aspect of the present invention, the switching system switches networks during the time between the transport of consecutive data packets.
• According to another aspect of the present invention, the system for determining network selection criteria uses two classes of parameters to determine the next network to use for transport of data.
• According to another aspect of the present invention, the selection system further determines a next network to switch to from the plurality of incompatible networks in accordance with the network selection criteria, when the selected network becomes unavailable. In addition, a monitoring system is provided which monitors the availability of the incompatible networks to determine whether the next network is available for data transport.
• The above-listed and other objects, features and advantages of the present invention will be more fully set forth hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention is further described in the detailed description which follows, by reference to the noted plurality of drawings by way of non-limiting examples of preferred embodiments of the present invention, in which like reference numerals represent similar parts throughout the several views of the drawings, and wherein:
• FIG. 1 illustrates a general overview of a remote network controller and mobile data controller in accordance with an aspect of the present invention;
• FIG. 2 illustrates a block diagram of the basic components of the remote network controller and mobile data controller of the present invention;
• FIG. 3 is a high-level flow chart, according to the present invention, of the outbound data from a wired communication network to a remote device;
• FIG. 4 is a high-level flow chart, according to the present invention, illustrating the flow of inbound data from a remote device to a wired communication network;
• FIG. 5 illustrates a block diagram of the components of a mobile interface in accordance with the present invention;
• FIG. 6 is a flow chart of the processing of an event handler and multithreading dispatcher associated with the mobile interface of the present invention;
• FIG. 7 is a flow chart for indicating the process flow of a process initialization module associated with the mobile interface of the present invention;
• FIG. 8 is a flow chart for indicating the processing of a mobile session manager associated with the mobile interface of the present invention;
• FIG. 9 is a flow chart of the processing steps for an inbound data event handler associated with the mobile interface of the present invention;
• FIG. 10 is a flow chart of the processing steps for an outbound data event handler associated with the mobile interface of the present invention;
• FIG. 11 is a flow chart of the processing steps for a process termination module associated with the mobile interface of the present invention;
• FIG. 12 is a flow chart of the processes associated with a host data controller interface module associated with the mobile interface of the present invention;
• FIG. 13 is a block diagram of the various components of a host data controller in accordance with an aspect of the present invention;
• FIG. 14 is a block diagram of the components comprising a service interface according to the present invention;
• FIG. 15 is a flow chart of the processing of an event handler and multithreading dispatcher associated with the service interface of the invention;
• FIG. 16 is a flow chart describing the process flow of a process initialization module associated with the service interface of the invention;
• FIG. 17 is a flow chart of the processing steps for an inbound data event handler associated with the service interface of the present invention;
• FIG. 18 is a flow chart of the processing steps for an outbound data event handler associated with the service interface of the present invention;
• FIG. 19 is a flow chart of the processing steps for a process termination module associated with the service interface of the present invention;
• FIGS. 20, 21,22,23A,23B and24 are flow charts of the various processes associated with a wired communication network interface module associated with the service interface in accordance with the present invention;
• FIG. 25 is a block diagram of the various components of a mobile data controller of the present invention;
• FIG. 26 is a block diagram of the various components of a remote gateway according to another aspect of the present invention;
• FIGS. 27 and 28 illustrate a block diagram of a remote network controller in accordance with still another aspect of the present invention, in which a subsystem synchronization process module is utilized;
• FIG. 29 illustrates a general overview of another embodiment of the present invention which includes a mobile router in accordance with an aspect of the present invention;
• FIG. 30 illustrates a schematic block diagram of the mobile router in accordance with an aspect of the present invention;
• FIG. 31 is an illustration of a block diagram of the functional components of the router in accordance with an aspect of the present invention;
• FIG. 32 is an illustration of a block diagram of the switch within the router according to the present invention;
• FIG. 33 is an illustration of a flow chart of the processing steps used by the router to initialize and build tables stored in the Router in accordance with an aspect of the present invention;
• FIG. 34 is a flow chart of the processing steps used by the router for checking availability of each network interface in accordance with an aspect of the present invention;
• FIG. 35 is a flow chart of the processing steps used by the router to account the availability of the channels and the user's configuration in order to decide which channel to use for transporting data in accordance with an aspect of the present invention;
• FIG. 36 is a flow chart of the processing steps used by the router for an error handler in accordance with an aspect of the present invention; and
• FIG. 37 is an illustration of the software architecture of the Router in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
• Referring now to the accompanying drawings,FIG. 1 illustrates a general overview of a remote network controller and a mobile data controller in accordance with an aspect of the present invention. InFIG. 1, awired communication network10 is shown as a host network system havingcommunications controllers15 and locally-attacheddevices12. Thewired communication network10 may be, for example, a Token Ring network or an Ethernet Local Area Network (LAN). The locally-attacheddevices12 may include a personal computer, a workstation, a printer or network server, and reside at a plurality of dispersed locations. According to the present invention, aremote network controller20 may also be provided which logically resides on thewired communication network10 and acts as a protocol-appropriate communications controller to send and receive data to and from thecommunications network10 and one or more remote ormobile devices52. For purposes of illustration, only one of theremote devices52 is shown inFIG. 1.
• Remote devices52 communicate via amobile data controller54 and a wireless radio-frequency (RF) communications link55 created by the user'sradio infrastructure56 to theremote network controller20. Themobile data controller54 may convert asynchronous data from theremote device52 into an appropriate protocol format of theradio infrastructure56. In accordance with an aspect of the present invention, theremote devices52, although not physically connected to thewired communication network10, are logically connected to thewired communication network10 through theradio infrastructure56 and theremote network controller20 and are indistinguishable from locally-attacheddevices12. Theremote devices52 may be, for example, a laptop computer, personal digital assistant (PDA), a credit card reader, or a global positioning system (GPS) receiver. Theradio infrastructure56 may comprise a conventional point to point or trunking radio system.
• The logical connection created by theremote network controller20 between theremote device52 and thewired communication network10 is “transparent” to the user of theremote device52, and to thewired communication network10. In accordance with an aspect of the invention, theremote network controller20 takes data transported by theradio infrastructure56, irrespective of the format protocol of the radio infrastructure, and converts the data into a format protocol recognized by the wirednetwork10. Similarly, theremote network controller20 of the present invention takes data from the wirednetwork10 and converts the data into a format protocol recognized by theradio infrastructure56. Accordingly, the user of theremote device52 does not have to perform any additional steps to send and receive data to and from the wiredcommunication network10, and thewired communication network10 does not have to perform any additional steps to send and receive data to and from theremote device52. The user of theremote device52 interacts with thewired communication network10 in a similar manner as a user of the locally-attacheddevices12. Similarly, thewired communication network10 interacts with theremote device52 in a similar manner as the wired communication network interacts with the locally-attacheddevices12.
• Referring now toFIG. 2, there is illustrated a block diagram of the basic components of theremote network controller20 of the present invention. Each component of theremote network controller20 will be generally described for introductory purposes and will later be described in greater detail below with reference to the accompanying drawings. The various components of thehost data controller22 and themobile data controller54 will also be discussed hereinafter with reference toFIGS. 13 and 25, respectively.
• As shown inFIG. 2, theremote network controller20 may comprise aservice interface30, amobile interface24, aninterprocess communication manager28, acontrol process module26, and aconsole interface34. Theremote network controller20 may be implemented through a collection of software program modules and hardware components working cooperatively. Theremote network controller20 itself may run on a standard platform, such as a personal computer (PC) equipped with a commercially available processor or multi-processor, e.g., an Intel or Motorola based processor or multi-processor, and a commercially available operating system, such as an MS-DOS or UNIX based operating system. Theremote network controller20 may also contain an Ethernet controller or suitable network controller card depending on thewired communication network10. In addition, theremote network controller20 may include random access memory and physical storage media including hard disk and tape storage devices.
• Thewired communications network10 is connected to theremote network controller20 by theservice interface30. Theservice interface30 handles all network connections. If severalwired communications networks10 are present, one or more service interfaces30 may be provided to handle wired network connectivity. Theservice interface30 connects to aninterprocess communication manager26. Theinterprocess communication manager28 manages all inter-process message routing within theremote network controller20. One or moremobile interfaces24 may also be provided to handle connectivity with the radio infrastructure(s)56. Eachmobile interface24 is also connected to theinterprocess communication manager28. Thecontrol process module26 of theremote network controller20 is provided to process management functions and data integrity. Thecontrol process module26 is connected to theinterprocess communication manager28 and theconsole interface34. Theconsole interface34 allows for user configuration and reporting of data.
• As further illustrated inFIG. 2, theremote network controller20 may be connected to ahost data controller22. One or morehost data controllers22 may be provided for connecting theremote network controller20 tospecific radio infrastructures56, e.g., a Motorola trunked radio. Thehost data controller22 may be connected to themobile interface24 of theremote network controller20.
• In the field, theremote device52 is connected to themobile data controller54 which, in turn, is connected to theradio infrastructure56 for transmitting and receiving data. Themobile data controller54 is responsible for connecting theremote device52 to theradio infrastructure56 and to provide protocol-independent asynchronous serial data transfer to and from theremote device52.
• In order to provide transparent data transportation, whereby the network protocols and the protocols of theradio infrastructure56 are transparent or invisible to the user, inbound asynchronous data from theremote device52 is collected and transported to thewired communication network10 in packets over theradio infrastructure56. The data is sent using the existing protocols of theradio infrastructure56. Theremote network controller20 accepts the data and encapsulates it into the appropriate protocol used by the wiredcommunication network10. The data is passed to thewired communication network10 in a similar fashion for passing data from any of the other locally-attacheddevices12. Similarly, outbound data to theremote device52 from the wiredcommunication network10 is removed from the network protocol by theremote network controller20. Theremote network controller20 then encapsulates the data into the appropriate protocol associated with theradio infrastructure56 and sends the data over theradio infrastructure56 to themobile data controller54. Upon receipt of the data, themobile data controller54 removes the data from the radio infrastructure protocol and asynchronously sends the data to theremote device52.
• In accordance with the present invention, multiple wirednetworks10 with different protocols may be linked to multiple RF environments in any combination by incorporating the remote network controller and mobile data controller of the present invention.
• FIG. 3 is a high-level flow chart for transporting outbound data from the wiredcommunication network10 to theremote device52. As shown inFIG. 3, when data is to be sent to theremote device52, theservice interface30 of theremote network controller20 accepts data from the wiredcommunication network10 atstep500. Theservice interface30 then converts the data from the protocol used by the wiredcommunication network10 and encapsulates it into an internal protocol used by theremote network controller20 atstep502. In addition, theservice interface30 may receive routing information from the wiredcommunication network10 as to whatremote device52 the data is to be passed, e.g., a network address or device identifier of theremote device52.
• Atstep504, theservice interface30 forwards the data to theinterprocess communication manager28. Theinterprocess communication manager28 accepts the data atstep506 and, atstep508, places the data in a queue for the appropriate destinationmobile interface24. The destinationmobile interface24 may depend on theradio infrastructure56 employed by the user. The outbound data that is to be passed from theinterprocess communications manager28 to themobile interface24 may be encapsulated in an internal protocol of theremote network controller20, along with routing information to specify theremote device52 to which the data is to be sent. Atstep510, theinterprocess communication manager28 notifies themobile interface24 that the data to be sent to theremote device52 is queued for the mobile interface. The particularmobile interface24 that the data is queued for depends on theparticular radio infrastructure56 employed to communicate with the destinationremote device52. Atstep512, themobile interface24 requests that the queued data be sent from theinterprocess communication manager28. The mobile.interface24 may request data when it is free to send the data to a destinationremote device52 and not handling another process. Atstep514, themobile interface24 accepts the queued data from theinterprocess communication manager28. Thereafter, atstep516, themobile interface24 determines, based on the queued data, the destination node address of theremote device52 to which the data is to be sent. Atstep518, themobile interface24 forwards the data to the appropriatehost data controller22 so that it may be sent over theradio infrastructure56 atstep520. According to an aspect of the present invention, thehost data controller22 may receive the data, remove it from the internal protocol and encapsulate the data into a packet determined by the protocol used by theradio infrastructure56. The packet of data may be broadcasted over theradio infrastructure56 so as to enable thehost data controller22 to communicate with multiplemobile data controllers54 simultaneously. The broadcasted data packet may include the identification of the specificmobile data controller54 to which the packet is to be delivered, so that only. uniquely identified mobile controller(s) may accept the packet.
• Referring again toFIG. 3, atstep522, themobile data controller54 receives the data from theremote radio infrastructure56 and decodes the data. The data packet, once received by themobile data controller54, is accepted and the data is removed from the packet. Atstep524, themobile data controller54 validates the data and, atstep526, sends an acknowledgment or rejection message to thehost data controller22 via theradio infrastructure56. According to the present invention, theremote network controller20 and thehost data controller22 may be responsible for ensuring the integrity of the data transported over the radio infrastructure. As such, an error detection/retry mechanism may be employed to detect and correct data transmission errors. After the integrity of the data is verified, themobile data controller54 atstep528 will forward the data to theremote device52. The data may be asynchronously transferred to theremote device52 through a serial connection.
• FIG. 4 is a high-level flow chart illustrating the processing of inbound data from theremote device52 to thewired communication network10. Atstep550, themobile data controller54 accepts data from theremote device52. At step552, themobile data controller54 formats and sends the data to theremote network controller20 via theradio infrastructure56, which may comprise a modem. The data may be transmitted using the appropriate protocol of theradio infrastructure56. The data may be modulated within themobile data controller54 prior to transmission via theradio infrastructure56. Themobile data controller52 may place the data from theremote device52 into packets to be sent over theradio infrastructure56. The packet size can be determined by one of three methods. The first is a maximum packet size. Once an upper limit of data is accumulated, themobile data controller54 may send the packet of information to thehost data controller22. For example, once 256 bytes of data are collected, the data may be sent by theradio infrastructure56 over the RF communications link55. The second method is a maximum time to wait before sending data. In this case themobile data controller54 will send a packet after waiting a predetermined period of time, no matter how much data is accumulated. The third method involves themobile data controller54 detecting a predefined “end-of-packet” character which causes all accumulated data to be transmitted.
• Atstep554, thehost data controller22 receives and decodes the data packet from the protocol of theradio infrastructure56. Generally, the data arrives as a packet of a predetermined size. Atstep556, thehost data controller22 validates the data and, thereafter, sends atstep558 an acknowledgment or rejection message to themobile data controller54 based on the validation process. According to an aspect of the present invention, thehost data controller22 may determine if the transmitted data packet is correct, or in error. Thehost data controller22 may also determine if the data packet has arrived in the proper sequence, and that the packet is not a duplicate. As discussed above, the inbound data may be removed from the packet and encapsulated in the internal protocol used by theremote network controller20. The internal protocol may contain additional information, such as the identification of themobile data controller54 which sent the information.
• Atstep560, thehost data controller22 forwards the data to themobile interface24. Themobile interface24 accepts the data from thehost data controller22 atstep562. Themobile interface24 validates the address of the source of the data (e.g., the particularmobile data controller54 or remote device52) atstep562. Atstep566, themobile interface24 forwards the data to theinterprocess communication manager28 which accepts the data atstep568. The mobile interface may also pass the routing information specifying theremote device52 from which the data originated. Atstep570, theinterprocess communication manager28 places the data into a queue for thedestination service interface30. The particulardestination service interface30 will depend upon whichwired communication network10 the data is to be delivered. Included in the information which is passed to theservice interface30 is the destination address (i.e., thecommunication network10 to which the data is to be delivered). Atstep572, theservice interface30, when available to handle data, requests the data from theinterprocess communication manager28. Theservice interface30 accepts the data atstep576 and converts the data into an appropriate form, i.e., protocol, usable by the wiredcommunication network10 atstep578. As a result, the data may be passed to the hardware device (e.g., an Ethernet controller) using the protocol required by the wiredcommunication network10. This configuration allows any existing network interface card to be used in conjunction with theremote network controller20, because the data is placed into the appropriate network protocol by theservice interface30 before it is transmitted to the wired network. Atstep580, theservice interface30 forwards the data to thewired communication network10.
• The validation process of the outbound data depicted inFIG. 3 and inbound data depicted inFIG. 4 does not depend on the type ofwired communication network10 employed by the user. Through a single validation process performed by thehost data controller22 and the mobile data controller54 (seesteps524 and526 inFIG. 3 andsteps556 and558 inFIG. 4), the integrity of the data transmitted from the wiredcommunication network10 to theremote device52 through theradio infrastructure56 is ensured. This validation process may include, for example, an error detection and retry mechanism to detect errors and to cause (when necessary) the retransmission of the data.
• Referring now toFIG. 5, there is illustrated a block diagram of the basic components of themobile interface24 of theremote network controller20 of the present invention. As noted above, themobile interface24 is responsible for interfacing theremote network controller20 with thehost data controller22 and theradio infrastructure56. Themobile interface24 may be a software interface that records statistical information related to inbound and outbound data. Themobile interface24 may also be responsible for error detection and correction, and establishing and managing the mobile data sessions with theremote devices52. The number ofmobile interfaces24 provided in theremote network controller20 depends on the number of different types ofradio infrastructures56 employed by the user. Each type ofradio infrastructure56 may have its own associatedmobile interface24.
• As shown inFIG. 5, themobile interface24 may include an event handler andmultithreading dispatcher60, aprocess initialization module62, amobile session manager64, an inbounddata event handler66, an outbounddata event handler68, aprocess termination module70 and a host datacontroller interface module72. The event handler andmultithreading dispatcher60 may contain high-level logic and be used to control the overall execution flow of themobile interface24. Theprocess initialization module62 may be utilized to acquire resources and establish the operation environment for the mobile-interface24 process. Theprocess initialization module62 may also be provided to initialize thehost data controller22.
• According to the present invention, themobile session manager64 may be provided to control the communications environment between themobile data controller54 and thehost data controller22. The inbounddata event handler66 responds to signals from thehost data controller22 indicating that inbound data is available and preprocess session control information. The outbounddata event handler68 is provided to respond to signals from theinterprocess communication manager28 indicating that outbound data is available or that a session control function is required. Theprocess termination module70 functions to release previously-acquired resources and terminate themobile interface24 process efficiently. The host datacontroller interface module72 handles low-level interaction with the associated host data controller(s)22.
• The process flow of the event handler andmultithreading dispatcher60 will now be described with reference toFIG. 6. Atstep600, the process begins when theremote network controller20 is powered up and initialized. Atstep602, theprocess initialization module62 is invoked (described below with reference toFIG. 7). Atstep604, the event handler andmultithreading dispatcher60 waits for an event (e.g., receipt of inbound data) to occur. While the event handler andmultithreading dispatcher60 waits for an event to occur,mobile interface24 may be placed in a “sleep” mode to conserve processor resources. Atstep606, once an event occurs, the event handler andmultithreading dispatcher60 determines if it is a recognized event. If the event handler andmultithreading dispatcher60 determines it is not a recognized event atstep606, processing returns to step604. If, however, the event handler andmultithreading dispatcher60 determines that the event is a recognized event atstep606, then processing continues atstep608, where the event handler andmultithreading dispatcher60 determines if the data was received from thehost data controller22.
• Atstep608, if the event handler andmultithreading dispatcher60 determines the data was received from thehost data controller22 the event handler andmultithreading dispatcher60 invokes the inbounddata event handler66, at step614 (described below with reference toFIG. 9) and processing continues atstep604. If atstep608 the event handler andmultitlireading dispatcher60 determines that the data was not received from thehost data controller22, then the event handler andmultithreading dispatcher60 determines whether the data was received from theservice interface30 atstep610.
• If the event handler andmultithreading dispatcher60 atstep610 determines that the data was received from theservice interface30, then atstep616 the outbounddata event handler68 is invoked (described below with reference toFIG. 10) and processing returns to step604. If the event handler andmultithreading dispatcher60 atstep610 determines that the data was not received from theservice interface30, then atstep612 the event handler andmultithreading dispatcher60 determines if there is a process termination request.
• If, atstep612, the event handler andmultithreading dispatcher60 determines there is a process termination request, then atstep618, theprocess termination module70 is invoked (described below with reference toFIG. 11). If, atstep612, the event handler andmultithreading dispatcher60 determines that there is not process termination request, then processing continues atstep604 to wait for another event.
• Referring now toFIG. 7, there is illustrated an exemplary flow chart for indicating the process flow of theprocess initialization module62 ofFIG. 5. Atstep620, the interprocess communications interface is setup. Atstep622, the operating environment parameters are parsed and processed. This includes thehost data controller22 parameters referenced insteps626,632 and634 below. Atstep624, memory is allocated for the session and other tables contained within themobile interface24, which are used to control data flow and other operations. Atstep626, thehost data controller22 parameters are accessed. Atstep628, a path to thehost data controller22 port is opened. Atstep630, thehost data controller22 then is prevented from monitoring for an event from the remote device(s)52. Step630 prevents erroneous transmissions that may arise if thehost data controller22 attempts to monitor aremote device52 before the initialization process is complete. Atstep632, thehost data controller22 communication parameters are set. Atstep634, the communication parameters are downloaded to thehost data controller22. After the initialization processes ofsteps632 and634 are completed, thehost data controller22 atstep636 is enabled to monitor the remote device(s)52. Atstep638, the entire initialization procedure is complete and processing returns to step604 inFIG. 6.
• Referring now toFIG. 8, there is illustrated an exemplary flow chart describing the logic flow of themobile session manager64 ofFIG. 5. Atstep640, themobile session manager64 handler is entered from the event handler andmultithreading dispatcher24 when remote data is detected. Atstep642, the remote identifier of theremote device52 is looked up in a session table. Atstep644, themobile session manager64 determines if the remote identifier was found in the session table. If themobile session manager64 determines that the remote identifier was found, the address is returned from the session table atstep646.
• If themobile session manager64 does not find the remote identifier atstep644, then atstep648 themobile session manager64 attempts to authenticate the remote identifier. Atstep650, the mobile session manager determines if the authentication is successful. If atstep650 the authentication is successful, then atstep656 thehost data controller22 is instructed to connect to theremote device52 based on the remote identifier. After thehost data controller22 is connected to theremote device52, theappropriate service interface30 is invoked atstep658. Atstep660, processing is complete. If atstep650, the authentication was not successful, the remote data is ignored atstep652, and a null session table entry address is returned by themobile session manager64.
• Referring now toFIG. 9, there is illustrated an exemplary flow chart of the processing steps of the inbounddata event handler66 ofFIG. 5. Atstep662, the inbound data event handler is invoked (fromstep614 inFIG. 6). Atstep664, the remote identifier of theremote device52 is checked against the session table. Atstep666, it is determined whether the inbounddata event handler66 found the remote identifier in the session table. If atstep666, the remote identifier is not found in the session table, the data is ignored and processing continues atstep604 inFIG. 6. If the remote identifier is found in the session table atstep666, the data is sent to theservice interface30 atstep670. Processing then continues atstep604 inFIG. 6.
• Referring now toFIG. 10, there is illustrated an exemplary flow chart of the processing steps of the outbounddata event handler68 ofFIG. 5. Atstep672, the outbound data event handler is invoked (fromstep616,FIG. 6). Atstep674, the session table is checked for the outbound data remote identifier. Atstep676, it is determined if the outbounddata event handler68 found the remote identifier in the session table. If atstep676, the remote identifier is not found in the session table, an error is logged and the data message is ignored. Processing then continues atstep604 inFIG. 6. If the remote identifier is found in the session table atstep676, the data is sent to theremote device52 as a single packet atstep680. Processing then continues atstep604 inFIG. 6.
• Referring now toFIG. 11, there is illustrated an exemplary flow chart of the processing steps of theprocess termination module70 ofFIG. 5. Atstep682, theprocess termination module70 is invoked (fromstep618 inFIG. 6). Atstep684, theprocess termination module70 determines if there are any active remote sessions. If, atstep684, it is determined by theprocess termination module70 that there are no active sessions, then atstep686 all files are closed and themobile interface24 terminates. If, however, it is determined by theprocess termination module70 that there are active sessions, then atstep688 all of the active sessions are issued a disconnect request. Atstep690, the process termination module waits for all active sessions to terminate. Once all active sessions have terminated atstep690, then all files are closed and themobile interface24 terminates atstep686.
• Referring now toFIG. 12, there is illustrated an exemplary flow chart of the processes associated with the host datacontroller interface module72 ofFIG. 5. The host datacontroller interface module72 consists of a number of discrete functions (e.g., Initialize, Command, Send Data, and Receive Data) which are called when needed by themobile interface24 and share common information about thehost data controller22. The host datacontroller interface module72 may access thehost data controller22 via a serial communications port which is assigned to themobile interface24 and remains fixed when theremote network controller20 is in operation.
• Ahost data controller22 initialize routine begins atstep692. The initialization routine may be initiated in accordance with step602 (seeFIG. 6) and steps632 and634 (seeFIG. 7). Atstep694, the serial communications port is accessed and setup. Thereafter, atstep696, the port handle and status is saved to be used by other processes within the host datacontroller interface module72.
• Ahost data controller22 command routine begins atstep698. The command routine may be initiated upon the occurrence of a recognized event (see, e.g.,step604 inFIG. 6) so that the appropriate control or operation- commands may be sent to thehost data controller22. Atstep700, thehost data controller22 is placed into a command mode. Atstep702, a command. (e.g., disconnect or receive) is issued to thehost data controller22 based on the event that is recognized. Atstep704, the host datacontroller interface module72 awaits a confirmation of acceptance of the command from thehost data controller22. Atstep706, the result of the command is returned to the host datacontroller interface module72.
• Ahost data controller22 send data routine begins atstep708 and may be initiated fromstep680 inFIG. 10. The send data routine is initialized so that data may be sent to the appropriateremote device52. First, the physical identification of theremote device52 is determined atstep710. Thereafter, the data to be sent to theremote device52 is placed into a packet atstep712, and sent to thehost data controller22 atstep714.
• Atstep716, ahost data controller22 receive data routine is initiated in accordance withstep670 inFIG. 9. The receive data routine is initiated so that data from theremote device52 may be received by theremote network controller20. Atstep718, data is accumulated within thehost data controller22 receive data routine (see,FIG. 12, step716) until a full packet of information is received. Thereafter, atstep720, the packet is identified as either session oriented or monitor oriented data. The identified data packet is then returned, atstep722, to themobile interface24 and sent to thewired communication network10 via theremote network controller20.
• Referring now toFIG. 13, in accordance with an aspect of the present invention, there is illustrated a block diagram of the basic components of the host data controller22 (see, e.g.,FIG. 2) of the present invention. Thehost controller22 may be physically connected external to theremote network controller20 via themobile interface24. Thehost data controller22 is specifically designed to convert theradio infrastructure56 protocol to the internal protocol of theremote network controller20. Typically, onehost data controller22 may be connected to eachmobile interface24; however, one or morehost data controllers22 may be connected for redundancy and greater reliability.
• As shown inFIG. 13, thehost data controller22 may comprise an RFcommunications interface module80, a remote network controllercommunications interface module78, and a configuration andmonitoring module82. Thehost data controller22 may comprise any combination of hardware and software to perform the functions described herein. For example, thehost data controller22 may comprise a commercially available processor or multi-processor with overlying application software. The software running in thehost data controller22 may be written in Z80 or other appropriate high-level language (e.g., Pascal). Thehost data controller22 may also contain a plurality of serial ports for communicating with other devices.
• The remote network controllercommunications interface module78 is connected to themobile interface24 of theremote network controller20 and is responsible for sending and receiving data to and from theremote network controller20. A subsystem port76 (e.g., an RS-232 adapter) may be used to connect the remote network controllercommunications interface module78 to themobile interface24 of theremote network controller20. If thehost data controller20 is connected to more than one remote network controller, then additional subsystem port connection(s) may also be provided to connect to theinterface module78 to the additional remote network controllers. The remote network controllercommunications interface module78 sends health and status information regarding thehost data controller22 to themobile interface24. This information informs theremote network controller20 that thehost data controller22 is operational and accepting data.
• The configuration andmonitoring module82 is specific to the type ofradio infrastructure56 employed. Software parameters, such as the number of subsystem ports, how often to send health and status requests, and a list ofmobile data controllers54 to which thehost data controller22 can communicate, may be set and stored in the configuration andmonitoring module82. The configuration andmonitoring module82 can also accumulate statistics which are passed to themobile interface24.
• In order to diagnose potential system errors in thehost data controller22, theremote network controller20 may test and analyze thehost data controller22 over a diagnostic port (not shown) to determine a cause of the system failure or error. The diagnostic port may be used not only to determine if thehost data controller22 is operational, but also to configure software parameters particular to the type ofradio infrastructure56. These parameters can be changed to communicate with adifferent radio infrastructure56 type as necessary.
• The RFcommunications interface module80 is responsible for sending and receiving the radio-frequency transmissions. The RFcommunications interface module80 is specific to theradio infrastructure56 in use and is connected to theradio infrastructure56 by acommunication line57. Again, because thehost data controller22 is designed to integrate with an existingradio infrastructure56, eachhost data controller22 is software configured to work with many different types ofradio infrastructure56 protocols for flexibility. Thehost data controller22 may be designed to be plugged into theremote network controller20, connecting to themobile interface24, and can simply be exchanged with a differenthost data controller22, or reprogrammed depending on theradio infrastructure56 employed.Host data controllers22 may be configured so as to be compatible with, for example, conventional point-to-point radio systems, conventional repeater-based radio systems, LTR Trunking, Motorola Trunking, Ericsson (EDACS) Trunking—Voice Path, EDACS RDI Trunking—Data Path, and EDACS IMC Voice Path radio infrastructures.
• Referring toFIG. 14, there is illustrated a block diagram of the components comprising the service interface30 (seeFIG. 2) of the present invention. Theservice interface30 is responsible for communicating to and from the wiredcommunication network10. Theservice interface30 is concerned only with the software level protocols of the wiredcommunication network10. The hardware interface to thewired communication network10 is accomplished by a known network control card, such as an Ethernet controller or a Token-Ring controller.
• The number ofservice interface30 connections to thewired communication network10 is dictated by the type ofwired communication network10. If thewired communication network10 uses asynchronous data transfer, there will be oneservice interface30 for every entry point, e.g., serial port, into thewired communication network10. In a local area network (LAN) environment, eachservice interface30 may handle a variety of different network addresses. Adifferent service interface30 may be used for each type ofwired communication network10.
• As shown inFIG. 14, theservice interface30 may include an event handler andmultithreading dispatcher90, aprocess initialization module92, an inbounddata event handler94, an outbounddata event handler96, aprocess termination module98 and a wirednetwork interface module100. The event handler andmultithreading dispatcher90 may contain high-level logic and be used to control the overall execution flow of theservice interface30. Theprocess initialization module92 acquires resources and establishes the operation environment of theservice interface30 process. The inbounddata event handler94 responds to signals from theinterprocess communication manager28 that inbound data is available and preprocess session control information. The inbounddata event handler94 may also handle asynchronous timer events. The outbound data-event handler96 is provided to respond to signals from wired communicationnetwork interface module100 that outbound data is available or that a timer event has occurred. Theprocess termination module98 functions to release previously-acquired resources and terminate theservice interface30 process gracefully. The wired communicationnetwork interface module100 handles low-level interaction with the associated wired communication network transport mechanism, i.e., communication protocol, being used.
• An exemplary process flow of the event handler and multithreading dispatcher90 (seeFIG. 14) of the present invention will now be described with reference toFIG. 15. Atstep800, the process begins when theservice interface30 is powered up and initialized. Atstep802, theprocess initialization module92 is invoked (described below with reference toFIG. 16). Atstep804, the event handler andmultithreading dispatcher90 waits for an event to occur in response, e.g., to network or remote device activity. While the event handler andmultithreading dispatcher90 waits for an event to occur, theservice interface30 may be placed in a “sleep” mode to conserve processing power. Atstep806, once an event occurs, the event handler andmultithreading dispatcher90 determines if it is a recognized event. Recognized events may include Initialize, Send Data, Receive Data and/or Terminate. If the event handler andmultithreading dispatcher60 determines it is not a recognized event atstep806, then processing returns to step804. If the event handler andmultithreading dispatcher90 recognizes the event atstep806, then processing continues atstep808, where the event handler andmultithreading dispatcher90 determines if the data was received from thehost communication network10.
• Atstep808, if the event handler andmultithreading dispatcher90 determines the data was received from the host wiredcommunication network10, the event handler andmultithreading dispatcher90 invokes the inbounddata event handler94, at step814 (described below with reference toFIG. 17) and, thereafter, processing continues atstep804. If atstep808 the event handler andmultithreading dispatcher90 determines that the data was not received from the host wiredcommunication network10, the event handler andmultithreading dispatcher90 then determines if the data was received from themobile interface24 atstep810.
• If the event handler andmultithreading dispatcher90 determines atstep810 that the data was received from themobile interface24, then atstep816 the outbounddata event handler96 is invoked (described below with reference toFIG. 18) and, thereafter, processing continues atstep804. If the event handler andmultithreading dispatcher90 atstep810 determines that the data was not received from themobile interface24, then atstep812 the event handler andmultithreading dispatcher90 determines if there is a process termination request.
• If, atstep812, the event handler andmultithreading dispatcher90 determines there is a process termination request, then atstep818 theprocess termination module98 is invoked (described below with reference toFIG. 19). However, if atstep812 the event handler andmultithreading dispatcher90 determines that there is not process termination request, then processing returns to step804 to wait for another event.
• Referring now toFIG. 16, there is illustrated an exemplary flow chart describing the process flow of the process initialization module92 (see, e.g.,FIG. 14) of the present invention. Atstep820, the interprocess communications interface is setup when theservice interface30 is started or powered up. Atstep822, the operating environment parameters are parsed and processed (i.e., the parameters of the operating environment are processed individually). Atstep824, any resources required (e.g., memory) are acquired. Thereafter, atstep826, the wired communicationnetwork interface module100 is invoked (seeFIGS. 20-24 discussed below). As discussed below, the wired communicationnetwork interface module100 may include several procedures associated with initializing the connectivity with thewired communication network10, reading data from the wiredcommunication network10, writing data to thewired communication network10, and terminating connectivity with thewired communication network10. In accordance with an aspect of the present invention, a unique set of procedures may be provided by the wired communicationnetwork interface module100 for each type ofwired communication network10. For example, a unique set of procedures may be provided for networks utilizing transparent asynchronous communications, TCP/IP stream sockets, Vehicle Location Reporting Facilities, Bidirectional Messaging Facilities, or Credit Card Verification Facilities.
• After the wired communicationnetwork interface module100 is invoked, the results of the previous operations performed atstep826 are sent atstep828 to themobile interface24. Atstep830, it is determined by theprocess initialization module92 if the wired communicationnetwork interface module100 was successfully invoked atstep826. If it is determined atstep830 that the wired communicationnetwork interface module100 was successfully invoked, then the initialization is complete atstep832, and processing returns to step804 inFIG. 15. If, however, it is determined atstep830 that the wired communication network interface module was not successfully invoked, then theservice interface30 is terminated atstep834.
• Referring now toFIG. 17, there is illustrated an exemplary flow chart of the processing steps for the inbound data event handler94 (see, e.g.,FIG. 14) of the present invention. Atstep836, the inbound data event handler is invoked (fromstep814 inFIG. 15). Atstep838, the data portion of the message sent by the wiredcommunication network10 is extracted. Atstep840, theservice interface30 requests a packet of data from themobile interface24. Atstep842, after the packet is accepted by theservice interface30, data is sent to the appropriate destination via thewired communication network10. The inbounddata event handler94 then waits for a disconnect request atstep844. If the inbounddata event handler94 receives a disconnect request atstep844, then a disconnect command is sent to themobile interface24 atstep846. Processing then continues atstep804 inFIG. 15. If, however, the inbounddata event handler94 does not receive a disconnect request atstep844, then the request received is ignored atstep848 and, thereafter, processing then continues atstep804 inFIG. 15.
• Referring now toFIG. 18, there is illustrated an exemplary flow chart of the processing steps for the outbound data event handler96 (seeFIG. 14) of the present invention. Atstep850, the outbound data event handler is invoked (fromstep816 inFIG. 15). Atstep852, the outbounddata event handler96 determines if there is a request (e.g., a disconnect request from the wiredcommunication network10 or the remote device52). If there is a request, then processing continues atstep856. However, if there is presently not a request, then atstep854 the outbound data from thenetwork10 is sent toremote device52 via themobile interface24. At step865, the outbounddata event handler96 then determines if a disconnect request has been received. If the outbounddata event handler96 receives a disconnect request atstep856, then a disconnect command is sent to themobile interface24 atstep860 by the interprocess communication manager28 (see, e.g.,FIG. 2). Processing then continues atstep804 inFIG. 15. If, however, the outbounddata event handler96 does not receive a disconnect request atstep856, then the request received is ignored atstep862 and processing then continues atstep804 inFIG. 15.
• Referring now toFIG. 19, there is illustrated an exemplary flow chart of the processing steps for the process termination module98 (seeFIG. 14) of the present invention. Atstep864, theprocess termination module98 is invoked (fromstep818 inFIG. 15). Atstep866, the wired communicationnetwork interface module100 connection is closed. Thereafter, atstep868, the processes associated with theservice interface30 are terminated.
• Referring now toFIGS. 20-24, there are illustrated exemplary flow charts of the various processes that may be performed by the wired communicationnetwork interface module100 of the present invention. The wired communicationnetwork interface module100 may consist of a number of discrete functions which provide theservice interface30 with a uniform means of communicating with various host computer networks, irrespective of the communication protocols of the wiredcommunication network10. All protocol and other feature-specific communications translation and handling is performed at the wired communicationnetwork interface module100. The wired communicationnetwork interface module100 may be designed for networks utilizing different implementations, such as transparent asynchronous communication, Hayes compatible communication, TCP/IP stream socket, Bidirectional Messaging Facilities, File Transfer Facilities, SNA Protocol Enveloping, Vehicle Location Reporting Facilities, Credit Card Verification Facilities, and Harris DNP 3.0 Frame Relay. As noted above, a unique set of procedures may be provided by the wired, communicationnetwork interface module100 for each type ofwired communication network10. Examples of several of these sets of procedures are provided below.
• Referring now toFIG. 20, there is illustrated an exemplary flow chart of the set of procedures associated with the wired communicationnetwork interface module100 that are designed for transparent asynchronous communication networks. Atstep900, an initialization process begins in accordance, for example, withstep802 ofFIG. 15. Atstep902, the serial port of the wiredcommunication network10 that is to be used is determined, and the identified port is opened or accessed at step904. Atstep906, the speed (bps), the parity (odd or even), and the data bits for communication with thenetwork10 are established along with other appropriate parameters.
• At step908 a data read operation begins. The data read routine may be invoked by the outbounddata event handler96 at step850 (seeFIG. 18). Initially, atstep910, the wired communicationnetwork interface module100 determines if there is data to be read from the serial port. If atstep910 the wired communicationnetwork interface module100 determines there is data to be read, then atstep916 the data is added to an accumulated data buffer within theremote network controller20. Atstep918, if the wired communicationnetwork interface module100 determines that the data buffer is full, then atstep914 the data accumulated in the buffer is returned to the calling module. If, however, atstep910 the wired communicationnetwork interface module100 determines there is no data to be read from the serial port attached to thenetwork10, then atstep912 it is determined if the inter-character time (e.g., a predetermined character receipt delay time) has been exceeded. If atstep912 the inter-character time has been exceeded, then atstep914 the accumulated data buffer is returned to the calling module to be further processed. Otherwise, if the inter-character time has not been exceeded, then processing continues atstep910 so that the wired communicationnetwork interface module100 may again determine if there is data to be read from the serial port.
• Atstep920, a write data routine is started. The write data routine may be initiated by the inbounddata event handler94 atstep836 inFIG. 17. Atstep922, the data is sent directly to the serial port of the wiredcommunication network10. The write data routine is thereafter completed.
• Atstep924, a terminate routine is initiated. The terminate routine may be initiated in accordance with a terminate request atstep818 inFIG. 15. In response to initiation of the terminate routine, the serial port of thenetwork10 is closed atstep926. Thereafter, atstep928, the serial port resource is released so it may be used by another process. Finally, atstep930, any data buffers in use are also released.
• Referring now toFIG. 21, there is illustrated exemplary flow charts of the set of procedures associated with the wired communicationnetwork interface module100 for networks utilizing TCP/IP stream socket connectivity. Atstep932, an initialization process begins in accordance, for example, withstep802 ofFIG. 15. Atstep934, a host network and serial port to be used are determined. Atstep936, an appropriate socket is created. Atstep938, the socket server is accessed for data transport.
• At step940 a data read operation begins. The data read routine may be invoked the outbounddata event handler96 at step850 (seeFIG. 18). Initially, atstep942, the wired communicationnetwork interface module100 determines if there is data to be read from the socket. If atstep942 the wired communicationnetwork interface module100 determines there is data to be read, then atstep944 the data buffer is returned to theremote network controller20 for further processing.
• Atstep946, a write data routine is started. The write data routine may be initiated by the inbounddata event handler94 atstep836 inFIG. 17. Atstep948, the data is sent by the wirednetwork interface module100 directly to the socket at thewired communication network10. The write data routine is thereafter completed.
• Atstep950, a terminate routine is initiated. The terminate routine may be initiated in accordance with a terminate request atstep818 inFIG. 15. Initially, the socket is closed atstep952. Thereafter, atstep954, the socket resource is released so it may be used by another process. Finally, atstep956, any data buffers in use are also released.
• Referring now toFIG. 22, there is illustrated exemplary flow charts of the set of procedures associated with the wired communicationnetwork interface module100 for use with networks utilizing Vehicle Location Reporting Facilities. Atstep958, an initialization process begins in accordance, for example, withstep802 ofFIG. 15. Atstep960 the wired communicationnetwork interface module100 determines a position recording file to be used to record data. The position recording file may be stored within the wiredcommunication network10. Atstep962, the position recording file is accessed from thenetwork10. Thereafter, atstep964, the recording interval is placed into a read buffer that may be provided to theremote device52 via themobile data controller54.
• At step966 a data read operation begins. The data read routine may be invoked by the outbounddata event handler96 at step850 (seeFIG. 18). Initially, atstep968, the wired communicationnetwork interface module100 determines if there is data in the read buffer. If atstep968 the wired communicationnetwork interface module100 determines there is data in the read buffer, then atstep970 the contents of the read buffer is returned to the calling module.
• Atstep972, a write data operation is started. The write data routine may be initiated by the inbounddata event handler94 atstep836 inFIG. 17. Initially, at step974, the wired communicationnetwork interface module100 determines if a full Global Positioning Satellite (GPS) message has been accumulated. If at step974, the wired communicationnetwork interface module100 determines that a full GPS message has not been accumulated, then no action is taken atstep980. If at step974, the wired communicationnetwork interface module100 determines that a fill GPS message has been accumulated, then the message is converted atstep976 to a standard form usable by the wiredcommunications network10. Atstep978, the position recording file at the host is appended with the GPS message.
• Atstep982, a terminate routine is initiated. The terminate routine may be initiated in accordance with a terminate request atstep818 inFIG. 15. The terminate routine may comprise closing the position recording file atstep984.
• Referring now toFIGS. 23A and 23B, there is illustrated exemplary flow charts of the set of procedures associated with the wired communicationnetwork interface module100 that are designed for networks utilizing Bidirectional Messaging Facilities or Store and Forward Messaging Facilities. Referring toFIG. 23A, atstep986, an initialization process begins. The initialization process may be started in accordance, for example, withstep802 ofFIG. 15. Atstep988, a message queue for theremote device52 is accessed. Thereafter, atstep990, if no queue exists for theremote device52, a message queue is created at theremote network controller20.
• At step992 a data read operation begins. The data read routine may be invoked by the outbounddata event handler96 at step850 (seeFIG. 18). Initially, atstep994, the wired communicationnetwork interface module100 determines if a message is in the process of being sent. If atstep994 the wired communicationnetwork interface module100 determines that a message is being sent, then atstep998, the current message segment is sent by theremote device52 to thewired communication network10. If atstep994 the wired communicationnetwork interface module100 determines that no message is being sent, then atstep996, the wired communicationnetwork interface module100 determines if there is a message queued. If atstep996 the wired communicationnetwork interface module100 determines that no messages are queued then no action is taken. However, if atstep996 the wired communicationnetwork interface module100 determines that there is a message queued for theremote device52, then the current message queued is sent atstep998. After the last segment of the message is sent, the wired communicationnetwork interface module100 may indicate that delivery of the message is pending to theremote device52 atstep1000.
• Atstep1002, a write data routine is initiated. The write data routine may be initiated by the inbounddata event handler94 atstep836 inFIG. 17. Initially, atstep1004, the wired communicationnetwork interface module100 determines if a new message is present. If atstep1004 the wired communicationnetwork interface module100 determines that a new message is present, then atstep1010 the wired communicationnetwork interface module100 starts a new queue entry. Thereafter, processing continues atstep1006, where the message segment is recorded. Atstep1008, the wired communicationnetwork interface module100 determines if this is the last segment. If atstep1008 the wired communicationnetwork interface module100 determines that it is the last segment, then atstep1012, the queue entry is closed and “Message Received” message may be placed into the read buffer atstep1014 to be sent to theremote device52. If atstep1008, the wired communicationnetwork interface module100 determines that it is not the last segment, then no action is taken.
• Referring toFIG. 23B, atstep1016, a terminate routine is started. The terminate routine may be initiated in accordance with a terminate request atstep818 inFIG. 15. Atstep1018, the wired communicationnetwork interface module100 determines if the terminate request has come in the middle of a message. If atstep1018, the wired communicationnetwork interface module100 determines that the request came in the middle of a message, then the message is purged atstep1022. Processing then continues atstep1020, where the wired communicationnetwork interface module100 closes the message queue.
• Referring now toFIG. 24, there is illustrated flow charts of the set of procedures associated with the wired communicationnetwork interface module100 designed for use with networks utilizing Credit Card Point-of-Sale Facilities. Atstep1024, an initialization process begins. The initialization process may be started in accordance, for example, withstep802 ofFIG. 15. In accordance with the invention, no action is required for the initialization procedure.
• At step1026 a data read operation begins. The data read routine may be invoked the outbounddata event handler96 at step850 (seeFIG. 18). Initially, atstep1028, the wired communicationnetwork interface module100 determines if there is a response from a server attached to thewired communication network10. If atstep1028 the wired communicationnetwork interface module100 determines there is a response from the server, then atstep1030 the response is read, and the response buffer is returned to theremote device52 atstep1032. If atstep1028 there is no response from the server, then no action is taken.
• Atstep1034, a write data operation is started. The write data routine may be initiated by the inbounddata event handler94 atstep836 inFIG. 17. Atstep1036, the wired communicationnetwork interface module100 first determines if a full request by theremote device52 has been accumulated. If atstep1036 the wired communicationnetwork interface module100 determines that a full request has not been accumulated, then theremote device52 continues to accumulate a request atstep1042. If at step1036 a full request has been accumulated, then atstep1038, the request is formatted for the server on thewired communications network10. Thereafter, the request is placed into the server file atstep1040.
• Atstep1044, a terminate routine is illustrated. The terminate routine may be initiated in accordance with a terminate request atstep818 inFIG. 15. According to the present invention, no action is necessary for the terminate routine.
• Referring now toFIG. 25, there is illustrated a block diagram of the various components of themobile data controller54, according to another aspect of the present invention. Themobile data controller54 may be specifically designed to match the asynchronous data transferred to and from theremote device52 to theradio infrastructure56 protocol. Typically, there is one type ofmobile data controller54 that is associated with ahost data controller22 which is connected to themobile interface24 of theremote network controller20. In addition, themobile data controller54 may have a unique identifier associated with it for routing purposes.
• In accordance with the present invention, themobile data controller54 may be implemented by any combination of hardware and software. For example, themobile data controller54 may comprise a commercially available processor with overlying software and random access memory. The software running in themobile data controller54 may be written in Z80 or other appropriate processor-based (i.e., native) assembly language and configured to thespecific radio infrastructure56. The software may specify the various voltage levels and logic signals necessary to communicate via theRF communications infrastructure56. As noted above, the mobile data-controller54 may translate and pass any protocols associated with thewired communications network10 to and from theremote device52 to make it appear to thewired communication network10 that theremote device52 is locally-attached.
• Themobile data controller54 is configurable over theradio infrastructure56, configuration information may be input by an operator at theremote network controller20 through the console interface34 (seeFIG. 2) and passed over theradio infrastructure56 to themobile data controller54. This allows parameters such as packet size to be changed at the host wiredcommunications network10 without the necessity of altering themobile data controller52 in the field.
• As shown inFIG. 25, themobile data controller54 may comprise an RFcommunications interface module106, a remote devicecommunications interface module102, and a configuration andmonitoring module104. Themobile data controller54 may be connected to theremote device52 via acommunication port108 for sending and receiving data. The remote devicecommunications interface module102 is connected to theremote device52 via thecommunication port108 and is responsible for sending data to, and receiving data from, theremote device52. Thecommunication port108 may comprise, for example, an RS-232 adapter.
• The configuration andmonitoring module104 is specific to the type ofradio infrastructure56 employed. Software parameters, such as the number of subsystem ports, how often to send health and status requests, and a list ofhost data controllers22 to which themobile data controller54 can communicate, may be set and stored in the configuration andmonitoring module104. The configuration andmonitoring module104 can also accumulate statistics which are passed to thehost data controller22.
• In order to diagnose potential system errors in themobile data controller54, an operator may be provided with the ability to field test and analyze the mobile data controller via an externaldiagnostic port112 to determine a cause of the system error or failure. Thediagnostic port112 may be used not only to determine if themobile data controller54 is operational, but also can be used to configure software parameters to determine the type of theradio infrastructure56. These parameters can be changed to communicate with a different type ofradio infrastructure56 as necessary.
• The RFcommunications interface module106 is responsible for sending and receiving the data via radio-frequency (RF) transmission. The RFcommunications interface module106 is specific to theradio infrastructure56 used, and is connected to theradio infrastructure56 through acommunication line110. Because themobile data controller54 is designed to integrate with an existingradio infrastructure56, eachmobile data controller54 may be software configured, for purposes of flexibility, to work with many types ofradio infrastructure56 protocols. The RFcommunications interface module106 may also send health and status information regarding themobile data controller54 to thehost data controller22. This information may inform theremote network controller20 that themobile data controller54 is operational and theremote device52 is accepting data.
• According to the present invention, the RFcommunication interface module106 may include a commercially available modem (not shown). The modem may be selected depending on the data rate(s) of thecommunication line100 and theradio infrastructure56. More than one modem may be provided if multiple data rates are required. Optionally, the modem can be implemented using a Digital Signal Processing (DSP) chip and associated software. The DSP chip can be a commercially available programmable signal processing chip. In such a case, the DSP implementation will allow a single modem to be changed (e.g., by uploading new parameters to the DSP software) in order to communicate with a plurality of different types ofradio infrastructures56 having distinct protocols and data rates.
• Similar to thehost data controllers22, themobile data controllers54 may be compatible with, for example, conventional point-to-point radio systems, conventional repeater-based radio systems, LTR Trunking, Motorola Trunking, Ericsson (EDACS) Trunking-Voice Path, EDACS RDI Trunking-Data Path, and EDACS IMC Voice Path basedradio infrastructures56.
• Referring again toFIG. 2, a brief description of theinterprocess communications manager28 will be provided. According to the present invention, theinterprocess communications manager28 is responsible for routing all communication between the various modules and interfaces within theremote network controller20. Theinterprocess communications manager28 creates a logical route from theremote device52 to theservice interface30 of the remote network controller. Theinterprocess communications manager28 passes routing information which determines from whichradio infrastructure56 andremote device52 the inbound data has come from, and to whichradio infrastructure56 andremote device52 the outbound data will be sent.
• Theinterprocess communications manager28 may also pass information generated by theremote network controller20, which is independent of the data and routing information. This information may include internal parameters and error detection codes. Theinterprocess communications manager28 also interfaces with thecontrol process module26. Thecontrol process26 may act as the “central hub” of theremote network controller20. Thecontrol process26 provides resource management, process management, session management, configuration management and system statistics management within theremote network controller20.
• As further shown inFIG. 2, theremote network controller20 also includes aconsole interface34. Theconsole interface34 may be adapted to allow a network operator to configure and control the wireless Network Interfaces described above, the mobile user characteristics and the configuration information of the wiredcommunications network10. Theconsole interface34 may be a stand-alone platform having a commercially available processor (e.g., an Intel or Motorola based processor) and an Ethernet controller card for communicating, for example, with anotherremote network controller20.
• Referring now toFIG. 26, there is illustrated aremote gateway120, in accordance with another aspect of the present invention. As shown inFIG. 26, theremote gateway120 is comprised of atransparent communications module122, a fieldservice interface module128, a configuration andhealth module124 and aRF communications module126. Theremote gateway120 is functionally similar to themobile data controller54. However, theremote gateway120 is a specific type of mobile data controller that may be used to attach to a remote telemetry unit for monitoring, for example, electrical power distribution.
• Thetransparent communications module122 is responsible for communicating with a terminal device, typically a Remote Telemetry Unit (RTU) located in the field, and accepts data from theRF communications module126. As shown inFIG. 26, thetransparent communications module122 may be connected to aRTU133 via acommunication line130. Thetransparent communications module122 does not recognize any protocol, but handles hardware flow control and buffering and packetizing. Data communication between thetransparent communications module122 and theRTU133 may be carried through a synchronous serial transfer.
• TheRF communications module126 is configured to communicate with theremote network controller20 using whatever protocol is required for data transport over theradio infrastructure56. The RFcommunications interface module126 interfaces with theradio infrastructure56 in a similar manner as previously described above with regard to the RFcommunications interface module106. The RFcommunications interface module126 accepts data from thetransparent communications module122 and delivers it to theradio infrastructure56 for transmission to the remote network controller. The RFcommunications interface module126 detects collisions with inbound RF data and restarts outbound transmissions. The RFcommunications interface module126 performs error/retry functions and notifies thetransparent communications module122 of successes or failures.
• The fieldservice interface module128 allows a technician to field test theremote gateway120 and troubleshoot the remote gateway should a system error or problem arise. An externaldiagnostic port112 connected to the fieldservice interface module128 may be provided for this purpose. The fieldservice interface module128 may interact with the configuration andhealth module124 to query, set, and reset local configuration of theremote gateway120.
• The configuration andhealth module124 may accept configuration information from theremote network controller20 via theradio infrastructure56 and adjust the operating parameters of theremote gateway120 accordingly. The configuration andhealth module124 may also monitor and determine if theRF communications module126 has successfully transmitted a packet of information to thehost data controller22 by analyzing the data stream. If a packet of information has not been successfully transmitted, the configuration andhealth module124 may direct theRF communications module126 to resend the packet of information to thehost data controller22.
• Referring now toFIGS. 27 and 28, there is illustrated a block diagram of an integratedremote network controller140 according to another aspect of the present invention. The components of theremote network controller140 that are similar to that discussed above with respect toFIG. 2 are designated with the same reference numeral and also with a prime (“′”) added thereto.
• As shown inFIG. 27, theremote network controller140 according to another aspect of the present invention may include one ormore service interfaces30′, aninterprocess communications manager28′, acontrol process26′, one or moremobile interfaces24′, and asubsystem synchronization processor150 which is used to link one or moreremote network controllers140 together (seeFIG. 28). As further shown inFIG. 27, one or morehost data controllers22′ are connected to themobile interfaces24′ and provided externally to theremote network controller140. The number ofhost data controllers22′ andmobile interfaces24′ may be dependent on the number ofradio infrastructures56 present. In addition, the number ofservice interfaces30′ may be dependent on the number and type ofwired communications networks10 present.
• According to an aspect of the present invention, tworemote network controllers140 may be linked by a local network152 (seeFIG. 28). This configuration provides a redundant system which insures greater reliability of communication between theremote device52 and thewired communications network10. For example, should any particular component fail, such as ahost controller22′ or aninterprocess communications manager28′, theremote device52 can still communicate with thewired communication network10 because of the redundancy of the components of theremote network controllers140 provided.
• There are two main implementations of this system according to the present invention. With the first implementation, only one of theremote network controllers140 is operating at any given time. Should the operationalremote network controller140 fail, the otherremote network controller140 may immediately take its place. For example, if remote network controller “A” fails, then remote network controller “B” may be activated to take its place.
• Under the second implementation, a distributed processing scheme is utilized and both of theremote network controllers140 are operated at the same time. According to the distributed processing scheme, the processing load (e.g., event handling and data transfer) may be distributed among the operationalremote network controllers140. Should a particular remote network controller140 (e.g., controller “B”) fail, the remaining operational remote network controller140 (e.g., controller “A”) will handle the entire processing load.
• The above-mentioned distribution of the processing load is generally a function of theradio infrastructure56, and not the processing capacity of theremote network controllers140. This is because performance increases are mainly based on the number of available communications channels, rather than the raw processing capability of theremote network controllers140 attached to thewired communications network10. For example, if theradio infrastructure56 is a trunking radio network with five channels, it is possible for all five channels to be simultaneously allocated and used by theremote network controllers140. On the other hand, if there is only one channel available in theradio infrastructure56, then only oneremote network controller140 can access theradio infrastructure56 at a time; as a result, no performance gain may be realized by employing multipleremote network controllers140 when only limited channels are available.
• As illustrated inFIG. 28, thelocal network152 is used to connect theremote network controllers140 together. Thelocal network152 may be, for example, an Ethernet local area network. Each of theremote network controllers140 includes a subsystemsynchronization process module150 that is connected to thelocal network152. Twoseparate console interfaces34′ may also be attached to thelocal network152. Eachconsole interface34′ may be attached to thelocal network152 to allow an operator to configure and control a particularremote network controller140.
• The subsystemsynchronization process module150 may be implemented through any combination of hardware and software and is responsible for keeping track of all routing tables and health and status information associated with both of theremote network controllers140. Each subsystemsynchronization process module150 is connected to aninterprocess communications manager28′ of one of theremote network controllers140 and may access all routing tables and health and status information with respect to the remote network controller from the interprocess communications manager. The health and status information and routing tables may be periodically updated based on the status of and events present at theremote network controller140. The periodically updated health and status information and routing tables may then be shared with the other subsystemsynchronization process module150 via thelocal network152 so that the tables and information associated with both of theremote network controllers140 is maintained in each of the subsystemsynchronization process modules150. Since the tables and information are periodically updated, a synchronization routine may be provided so that the information and tables are sent to the respective subsystemsynchronization process modules150 at predetermined intervals. If a particular subsystemsynchronization process module150 does not send or receive the tables and information, or if a particular subsystemsynchronization process module150 sends information indicating that one of theremote network controllers140 has malfunctioned, the other subsystemsynchronization process module150 may reroute any existing connections to thehost data controllers22′ and to the wirednetwork10 of the malfunctioningremote network controller140 to the remaining operationalremote network controller140.
• As further shown inFIG. 28, thehost data controllers22′ have two ports,154 and156, that are connected to a differentremote network controller140. As inFIG. 2, theremote network controller140 communicates to thehost data controller22′ and sends health and status information through the ports. If thehost data controller22′ does not receive information that one of theremote network controllers140 is operational, thehost controller22′ can switch ports, e.g., fromport154 toport156, in order to communicate with the otherremote network controller140.
• While the invention has been described with references to several exemplary embodiments, it is understood that the words which have been used herein are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, without departing from the scope and spirit of the invention in its aspects.
• For example, althoughFIG. 28 only shows tworemote network controllers140 that are connected by alocal network152, it is possible to connect two or more remote network controllers by thelocal network152 to provide increased redundancy. In addition, a plurality oflocal networks152 may be provided to connect the remote network controllers. Other modifications to the present invention may include selectively processing inbound and outbound data in a different logic order and/or by different components. In accordance with such a modification, processing functions may be performed only by the control process, or in the interprocess communication manager. Another application may be combining the mobile interface with a host data controller, and placing the integrated unit within the remote network controller.
• Referring now toFIG. 29, therein is illustrated a general overview of another embodiment of the present invention which includes amobile Router200 in accordance with an aspect of the present invention. TheRouter200 provides the mobile application ordevice52 with the capability to selectively transmit and receive data over a plurality ofradio frequency infrastructures56 and/or the public switched telephone network58 in accordance with user configured parameters.
• Referring now toFIG. 30, therein is illustrated a schematic block diagram of themobile Router200. In the following description of theRouter200, each of the elements will be initially generally described and in greater detail thereafter. As shown inFIG. 30, the mobile application ordevice52 may be attached to multiple Networks by theRouter200 through Network Interfaces214A-D, a Router Core204, and aSwitch212. The Network Interfaces214A-D provide connectivity for data between theSwitch212 and the various Networks infrastructures (e.g.,radio infrastructures56 and public switch telephone network58) through which the mobile device orapplication52 connects to the communications network10 (seeFIG. 1). TheSwitch212 is actuated by the Router Core204, and sends data to a fixed host application or device (e.g., RNC20) via the selected network. The Network Interface214 provides information to theNetwork Availability process210, which sends this information to theDecision process206. TheDecision process206 operates in accordance with User Configured parameters208 which specify when and through which Network the data is to be transmitted. Thedecision process206 monitors the User Configuration parameters208, and theNetwork Availability210. When the Decision process206 (in accordance with User Configuration208 parameters) specifies that a Network (e.g., Network3) different than the Network currently in use (e.g., Network1) should be used, theDecision process206 checks theNetwork Availability210 for the particular Network to be switched to. If the Network is available, theDecision process206 instructs the Router Core204 to switch to the new Network. The Router Core204 then updates routing tables (not shown) maintained within the Router Core204 to reflect the new data path, and actuates theSwitch212 to connect to the new Network. Data may then flow over the new Network. In accordance with an aspect of the present invention, data may flow inbound to the fixed host through one Network, and outbound to the remote mobile Application ordevice52 through the same Network, or through a different Network.
• With reference toFIG. 30, the mobile application ordevice52 may comprise a software application running on a portable or laptop computer performing a variety of functions as programmed by the software application (e.g., database services). The Application ordevice52 may also comprise a special purpose device designed to perform a particular function, such as a credit card reader or barcode scanner. The Application ordevice52 may generate a data stream which is sent to a fixed location (e.g., a host computer infrastructure10).
• An exemplary application running on themobile device52 is a mobile remote client application which provides the remote user with the capability to send and retrieve data from a fixed database server application. The data may consist of customer records which, for example, may be used by service personnel operating a fleet of vehicles to service customers scattered about a wide geographic area. In the exemplary application, the mobile client application may request customer records from the fixed database server, and display the records for viewing by mobile service personnel. The mobile client application may send updated records to the fixed database as the service personnel finish assigned tasks. The updated records may contain a service history, equipment upgrades, and repairs for each customer.
• Another exemplary application running on themobile device52 may be a client application which retrieves a list of dispatched jobs to be performed by the service personnel during each day. The jobs may be uploaded to the remotemobile device52 each morning and stored in another client application in themobile device52. As the service personnel change job locations, the status of each job may be updated to indicate a status, e.g., en route, arrived and finished with comments. The status may be sent from the application to the fixed home office, so a dispatcher at the home office is aware of the locations of service personnel in the field.
• By way of non-limiting examples, themobile device52 may comprise a portable or laptop computer; a computer having an embeddedRouter200; a terminal or terminal emulator; a data gathering device (e.g., a SCADA system or remote telemetry system for obtaining data from a remote location for forwarding to a central location for processing); a card-swipe reader device (e.g., credit/debit/bank cards) for use in a mobile billing application, such as a taxi or mobile food cart; a smart-card reader; a logging device, such as those used in a package delivery system or fleet; a device for reading bar codes (e.g., for inventory control); and a remote application with data to send or to receive, from a fixed application or device (e.g., remote diagnostic tool). The above-noted applications are provided merely for exemplary purpose, and other applications andmobile devices52 may be used with theRouter200 of the present invention.
• Typically the device orApplication52 sends and receives data using a variety of protocols (e.g., Internet Protocol (IP)/transparent (via MDC 54)/ack-nack, etc.). The use of a variety of protocols provides for open transport of data throughout many networks, and in particular, networks which support open standards such as IP. However, many proprietary networks which require interface and/or protocol translation remain in use. In theRouter200 of the present embodiment, the function of interfacing with networks and protocol translation may be performed by the Network Interfaces214A-D.
• According to another aspect of the invention, other types of devices may be connected to the Network Interface214. Such devices may be used for functions other than data and voice communication. By way of non-limiting examples, these devices may include Global Positioning System (GPS) receivers and application processors.
• The Router Core204 is a function which shuttles messages between the Application orDevice52 and the various Networks. In accordance with the present embodiment, the router Core204 may control which network of a plurality of usable network messages are to travel over, and connect access ports (described below) to each Network and the Application orDevice52.
• The-Router Core204 may also comprise a list of all possible “names” or “addresses” to which data may be sent, or from which data may be received. The local “names” or “addresses” of the Router Core204 are stored in tables within a memory (not shown) of the Router Core204. Thus, the Router Core204 may serve as a communications “address book” for theRouter200 of the present embodiment. The Router Core204 also checks all messages passing through, and decides, based on the address and/or name entries in the tables, if the message is relevant to the attached Application orDevice52, or to the fixed host (e.g., RNC20). The address of the fixed host may be stored in the Router Core table as well. In accordance with the table entries, received messages may be determined to be valid or invalid. The Router Core204 may also actuate theSwitch212 in accordance with the output of thedecision process206. TheSwitch212 is actuated such that incoming and outgoing messages can be sent through the “current” network, as determined by the decision function206 (to be described below).
• TheSwitch212 may comprise a message multiplexor, i.e., theSwitch212 performs a one-to-many function for in-bound messages (to the fixed hosts), and a “many-to-one” function for outbound messages (from the fixed host). As noted above, the appropriate network selection is made by the Router Core204 in accordance with the output of thedecision process206. Messages travel through theSwitch212, the Router Core204, and the current Network Interface214.
• Referring toFIG. 32, theSwitch212 may be implemented using a combination of hardware (e.g., multiple- electronic ports, one per Network Interface214) to perform the physical connection process212B, and software (e.g., handlers which are interrupted at each character to move the character to either the Router Core204 (outbound), or to the current Network Interface214 (in-bound)) to perform theswitch logic process212A.
• As a non-limiting exemplary hardware implementation, theSwitch212 may comprise an 80386EX microprocessor, running at 33 MHZ, 256 kilobytes of FLASH ROM, 512 kilobytes of static RAM, six asynchronous serial ports, two TTL-to-RS232 convertors interfacing with two of the six serial ports directly to compatible devices external to theSwitch212, and four internal TTL serial interfaces to internally-mounted daughter boards, which carry Network Interfaces214A-D. Each Network Interface214 mounted on a daughter board may include a power supply for the Network Interface, a serial interface to the 80386EX microprocessor, and an interface to the outside network. The outside network may be a radio, a LAN, an antenna (for internally-mounted radios in the Network Interface214 ), or other device accepting or supplying data from/to theRouter200.
• The Switching function of theSwitch212 is provided by each serial Network Interface port at the 80386EX microprocessor, and the software residing in FLASH ROM. The software logic determines which Network Interface to use for transmission and receipt of data. The decision is implemented in the Switch, by selecting a physical serial port (and therefore which Network Interface) is to be used as the current Network. The Decision software in the FLASH ROM instructs the microprocessor to send the data to a specific serial port (which is mapped to specific physical addresses within the address range of the 80386EX microprocessor). The microprocessor then constructs the next message in the message buffers in RAM, and sends the message through the specific serial port which is designated as the “current Network” Interface port. The data then goes to the Network Interface (e.g.,network interface214A) connected to that specific serial port and on to the Network infrastructure. Received data is input to the Network Interface (e.g., network interface214B which may be set to the “current Network” serial port) and the microprocessor, where the received data is processed by the microprocessor. In accordance with an aspect of the present invention, messages which are received through Network Interfaces which are not designated as the “current Network” are ignored.
• The Network Interfaces214A-D are devices which present data to, or obtain data from the radio operating at the various R.F. Network frequencies, bandwidths, and modulations. The Network Interfaces214A-D may provide a port through which messages pass, to and from theSwitch212. The messages are typically in the form of a sequence of serial digital bits. The Network Interfaces214A-D-also may provide a modulator/demodulator function which transforms the digital data into an analog form which may be easily sent through the R.F. Network voicepath, based on characteristics of the assigned frequency band of the R.F. Network. The characteristics of analog transmissions are typically bandwidth (in Hertz, or cycles per second), noise present in the Network, and assigned frequency of the R.F. Network. Further, the Network Interfaces may interface with a radio, which may be included within the Network Interface214, or may be mounted externally to the Router200 (as shown inFIG. 29). The Network interface214 radio interface comprises the actual physical connections to the radio for the voicepath data, the muting function (if present and/or required) and the functionality for issuing a Press-to-Talk to the radio, and for receiving the Transmit Grant signal from the radio; both are used for handshaking between the radio network and the Network Interface214. This handshaking may be necessary for proper timing of the data out onto the RF Network. The muting function is used for silencing received signals which represent data, rather than voice traffic, which enables a remote user to mute the audible noise of the data traffic, which can be annoying to the remote user.
• Examples ofNetwork Interface214A-D include theMDC 54 and the NovaTel Wireless NRM-6812 Cellular Digital Packet Data (CDPD) modem. Where the network interface214 comprises theMDC 54, the radio is mounted external to theMDC 54, whereas in the NovaTel example, the radio and the network interface are integrated into a single unit.
• As noted above, the Network Interfaces214 provide connections to various types of networks. These networks may be wired (for example Public Switched Telephone Network58), or wireless (for example Cellular Digital Packet Data (CDPD)). The following non-limiting list includes networks that may be interfaced to theRouter200 by the Network Interfaces214A-D: private voice radio including conventional and trunked radios (e.g., using MDC 54), Cellular Digital Packet Data (CDPD), Spread Spectrum (e.g., direct sequence and channel-hop), GSM, GPS receiver, satellite transponder, RDI (Ericsson) interface, AMPS, RAM Mobile (Mobitex), RS232, RS485, Angel (AT&T), Asynchronous Transfer Method (ATM), Integrated Services Digital Network (ISDN), public switched telephone network (PSTN (POTS) telephone network), Ethernet, Ardis, Personal Communications Services (PCS), and any other network which is either transparent or operates using a specific protocol.
• The specific protocols to the above-listed networks are implemented in the Network Interfaces214A-D. These protocols may be very different, and therefore incompatible with each other. Additionally, a translation device may be provided in each Network Interface214 to translate between IP and the particular network protocol. By providing such a translation device, the Application orDevice52 can use IP data regardless of the particular network the Application orDevice52 is actually using.
• Referring toFIG. 31, a description of the functional components of theRouter200 will now be described. TheRouter20 may be implemented as an autonomous device with multiple connections to the networks through which data is to be routed. The user Configuration Interface208 provides a means whereby an external device such as a keyboard/terminal may be used to supply configuration information such as preferred routes, network node addresses, etc. to the router. Such information is accepted by the Configuration Interface208 and is placed into a non-volatile store (e.g., memory) which may be queried by other router components. In addition, capability may be provided whereby diagnostic information may be requested from the router and sent to the terminal device for evaluation by a technician.
• The Router Core204 is responsible for making all routing decisions. For a given destination network address specified within a data packet or datagram received from one of thenetwork interface drivers215A-D, the most-preferred path will be selected and the data packet or datagram forwarded through the preferrednetwork interface driver215A-D. Routing decisions are generally based upon such metrics as network speed and interface availability. Other metrics such as destination network, time of day, type of data, etc. may also be incorporated into the routing decision. Further, routing decisions may be made at the packet level such that each individual packet of data may be transmitted and/or received on different networks in accordance with the user configured parameters208.
• Exemplary Network Drivers215A-D may include an Ethernet Driver, a Token-Ring Driver, and a Serial PPP Driver. The Ethernet Driver provides a means for sending and receiving data through an Ethernet-type network. The function of the driver is to shield the Router Core from the details of network media access. The Token-Ring Driver provides a means for sending and receiving data through a Token-Ring-type network. The function of the driver is to shield the Router Core from the details of network media access. The Serial PPP Driver provides a means for sending and receiving data through a PPP-based serial data link. The function of the driver is to shield the Router Core from the details of network media access.Other drivers215A-D may be provided to interface with other types of networks as necessary.
• The Network Availability210 (see alsoFIG. 30) is a function which periodically interrogates each installed Network Interface214 in theRouter200 and may determine if the Network Interface214 is installed; if the Network Interface214 is properly configured and functioning properly; if the Network Interface214 is connected to the Network, on-line, and available for sending/receiving messages; and if the Network Interface214 is in good health. The above interrogation process may be accomplished by monitoring a timer tick (provided by the switch microprocessor), which instructs theNetwork Availability210 to query each Network Interface214. When the timer tick occurs, theNetwork Availability210 function interrogates each Network Interface214 as noted above. The status of each Network Interface214 is then passed to theDecision process206, which determines what the “next Network” will be if the result of the interrogation indicates that the “current Network” is experiencing transmission problems.
• TheNetwork Availability210 of each Network Interface214 is determined in a manner specific to the particular interfaced Network. For example, if the Network is CDPD, theNetwork Availability210 interrogates the network to determine if the Network Interface214 is currently registered with the Network, and therefore active. Also, in the CDPD network, the Network Availability214 determines if the Received Signal Strength Indication (RSSI) is sufficient to transmit relatively error-free data. For example, in the NovaTel CDPD Network Interface a RSSI of 100 dBm will provide for good data transmission qualities. Thus, if theNetwork Availability210 function queries the NovaTel CDPD Network Interface for the RSSI, and the response is −110 dBm, then the signal is too weak for error-free transmission, and therefore cannot be used at this time. This information is passed to theDecision process206 to determine if the “current Network” should remain the “current Network”, and if not, to determine what the “next Network” should be.
• The User Configuration208 block is used to define user configurable parameters by which the Router Core204 selects the “current Network” and the “next Network”. The Router parameters may include the date and time (e.g., yr-mo-da, hh:mm:ss), and the Network Interface214 installed in each of the internal slots of theRouter200. According to the present embodiment there are six internal slots to accommodate Network Interfaces to any of private voice radio using e.g., theMDC54 and a variety of radios, both conventional and trunked; Cellular Digital Packet Data (CDPD), such as Sierra Wireless or NovaTel CDPD modems; spread spectrum, either direct sequence, or channel-hop, as Xetron Hummingbird spread spectrum modem; GSM, such as Ericsson serial GSM module; GPS receiver, such as Motorola VP Encore GPS receiver, or Trimble SVEE Six receiver; satellite transponder; RDI (e.g., Ericsson) interface, implemented via a software protocol module and quasi-RS232 interface to radio; AMPS; RAM Mobile (e.g., Mobitex); RS232 default and fixed for example inslots 1 and 2; RS485; Angel (e.g., AT&T); ATM; ISDN; PSTN; Ethernet; Ardis; PCS; any other network which is either transparent or operates using a specific protocol; and none. Although six slots are disclosed herein, other numbers of slots may be provided.
• Other user configurable parameters include: the priority of each internal slot, (e.g., 1 to 6) where the slot with priority 1 is the default startup slot and Network; baud rate of each slot (a default rate may be set to 9600 bits per second, but may be configured to be any standard baud rate, divisible by 300, up to 115.2 kilo bits per second); cost per kilobyte per slot (e.g., $0.xx per kilobyte where the least costly slot that is available and highest priority will be default); protocol per slot (e.g., none, Point to Point (PPP), Serial Line Internet Protocol (SLIP), Hayes “AT” commands, transparent); slot mode, for example, transparent, PSTN, cellular, IP, receive only; slot name or address or phone number; slot to be used for diagnostics (e.g., default may be set to slot 2); slot muting to be used (e.g., none, PL, DTMF, other); number of retry transmissions per Network Interface (per slot) before declaration of Network Interface failure (e.g, 0-10); if slot Network Interface needs to be configured before it can operate (e.g., y,n); slot to be used for remote display (e.g., default may be set to slot 2); slot to be used for Device or Application52 (e.g., a connection to a mobile computer; default is slot 1); and frequency at which Network Availability210 is checked (e.g., default may be set to five seconds). Other user configurable parameters may be introduced and configured as necessary.
• The User Configuration208 function provides the user with the capability to instruct theRouter200 how to select a particular Network. These metrics may include, but are not limited to: which Network is connected to which Router port, time of day and date, priority (switching sequence) of each Network, cost per packet of each Network, and preferred default Network.
• On power up, the User Configuration208 is checked to determine if it is current. If the User Configuration208 is determined to be out of date, the end user is requested to input a configuration. The user is notified by blinking LEDs on the front panel or by a message sent to themobile device52. If the User Configuration208 is determined to be current, no user input is requested.
• Further, each Network is continuously evaluated for health and connectivity status. There are a number of parameters which are examined to determine this, including, but not limited to: Received Signal Strength Indication (RSSI), Clear to Send (CTS), Channel Clear/Channel Ready, and Transmit Grant.
• TheDecision process206 continuously examines the User Configured parameters in the user configuration block208, to determine the next Network to use, in case the current Network becomes unavailable to send or receive data. Such an unavailability may arise because the remote user (and consequently the Router200) has moved beyond coverage of the Network, or because a problem has occurred with the current Network or the Network Interface214.
• After theDecision process206 has determined the next Network to use, thedecision process206 queries theNetwork Availability210. If the next Network is available, then theDecision process206 updates the routing tables in the Router Core204. The Router Core204 will then actuate theSwitch212 to physically connect the next Network as the current Network.
• TheDecision process206 uses the User Configuration208 parameters defined above to determine the specific criteria for each slot, to be used when deciding if the current Network is to remain the current Network, and if not, what the next Network shall be. Once thedecision process206 has made a tentative decision to switch to another Network (i.e., the next network is to become the current network), it checks theNetwork Availability210 to ascertain if the Network is actually installed, configured, on-line, and in good health. For example, if the current Network is configured aspriority #3, and theNetwork Availability210 of thepriority #2 Network updates to, for example, “installed, configured, on-line, and in good health”, then thepriority #2 Network becomes the next Network. TheDecision process206 will instruct theSwitch212 to switch thepriority #2 Network to the current network. Should theDecision process206 decide to change Networks, it conveys an instruction to the Router Core204 by instructing the Router Core204 what the next Network Interface214 is to be.
• The process of theDecision process206 checking the User Configuration208 and theNetwork Availability210 continues indefinitely, and is described in detail inFIGS. 33-36. Generally, the process helps to guarantee that the mobile user always has access to a Network for sending and receiving data. This process also allows what is known now as “seamless roaming”. This means that the mobile user can move between Networks and continue to have reliable data transmission on the different Networks.
• FIGS. 33-36 illustrate the logic of the software in the router. Referring now toFIG. 33, there is shown an exemplary initialization routine which builds the tables in theRouter200. Upon initialization of the system, atStep310 the first channel priority is checked. AtStep312, it is determined whether or not the first channel is being examined. If it is the first channel, atStep314, table entries for the first channel are built. Information which is included in the table may be, e.g., IP address of the destination, intervening intermediate IP addresses, the assigned port, channel priorities, and the application being used. Typically channel one is assigned the highest priority. After the tables are built, the processing increments to the next channel atstep316. FromStep316, processing returns to Step312. If atStep312 it is determined that the channel being checked is not the first channel, processing proceeds to Step320 to query whether all channels have been checked. If all channels have not been checked, processing returns to Step314 to continue building the table entries viasteps314 and316 until all channels have been checked.
• Once it has been determined that all channels have been checked, atStep322 it is determined whether any tables have been built. If no tables have been built, at Step324 a configuration error is recognized and the processing stops. Tables may not have been built previously, e.g., if there are problems with the IP address, i.e.; there was no destination address. If atStep322 it is determined tables were already built, processing proceeds to Step326 where all channels are initialized and data transportation begins via the first channel.
• From Step326 the processing proceeds to Step328, also shown inFIG. 35, which illustrates an exemplary flow diagram of theRouter200 logic for accounting the Network Availability210 (FIG. 30) and User Configuration208 (FIG. 30) to decide which channels to use for data transport. Beginning atStep328, processing proceeds to Step330 where the channel is set to the current channel in a database which is described in more detail below. From there, processing proceeds to Step332 to retrieve the next channel to switch to from the database. The database is stored in flash memory and contains configuration information for each channel including how each channel is set up in theRouter200 and what configuration values are for eachNetwork Interface214A-D. In addition, the database stores which channel is current and the history of previous current channels. The tables discussed with reference toFIG. 33 atStep314 are also stored in the database.
• At step334 a determination is made as to whether the previous channel is available. Of course if this is the first time through, no previous channel will exist. If the previous channel is not available, at Step336 a determination is made as to whether the next channel is available. If the next channel is available, at Step338 a determination is made as to whether or not the priority is lower and it is time to switch. The determination is made by looking at the information in the User Configuration208 (FIG. 30). If it is time to switch, at Step340 a switch to the next channel is made. From there, processing continues to step341, where it is determined if the channel was switched. If the channel was switched, processing continues to step343 where a ping is sent to confirm the path is available. Fromstep343, the processing continues to Step342, also shown inFIG. 34. If, atstep341, it is determined the channel was not switched, processing continues to step342.
• Returning to Step334, if it is determined that a previous channel is available, atStep344 an inquiry is made as to whether or not the previous channel has a higher priority and it is time to switch. The determination is made by consulting the information in the User Configuration208 (FIG. 30). If it is determined the previous channel is a higher priority and it is time to switch, at Step346 a switch to the previous channel is made. FromStep346, the processing proceeds to Step341 as previously described.
• If atStep344 it is determined that it is not time to switch and the priority is not higher, processing proceeds to Step336 where it is determined whether the next channel is available. If the next channel is not available, atStep348 the current channel is not switched and the processing proceeds to Step341 as described above. If atStep336 the next channel is available, then atStep338 the inquiry into priority and time to switch is made as previously described. AtStep338, if it is not time to switch and the priority of the next channel is not lower, theRouter200 stays on the current channel atStep348.
• Refer now toFIG. 34 which illustrates a flow chart of exemplary logic for checking the availability of each network interface. Starting atStep342 processing proceeds to Step344 where the status of the channel being used is recorded in the database. Furthermore, atStep344, theRouter200 front panel LED's are updated. If atStep346 it is determined the availability of all channels has not been checked, atStep348 the next channel is identified and atStep350 the next channel's availability is polled. A channel is not available if it is being used for amobile device52 i.e. the channel is already one end of the network. If the channel is not available, the processing returns to step348. If the channel is determined to be available atstep350, processing proceeds to Step328 also shown inFIG. 35.
• If atStep346 it is determined that the availability of all channels has been checked, atStep352 the availability of the present channel is determined. If the present channel is available, a connection is made atStep354. If the present channel is not available, processing proceeds to Step356 for error handling. The error handling procedure is discussed with reference toFIG. 36 below. Upon completion of the error handling procedure, atStep360 the channel is set equal to one atStep362. AtStep350, the procedure continues as previously described.
• Referring now toFIG. 36, which is an exemplary flow diagram of the Router,200 error handling logic,Step356 continues fromFIG. 34. AtStep370, the present channel is deemed to be non-available. AtStep372, the next and previous channels are also confirmed to be non-available. AtStep374 an error is indicated to the device or application. AtStep376 an availability routine is run such as that described previously. From the availability routine at Step36, the processing continues to Step360 as discussed with reference toFIG. 34.
• TheRouter200 of the present invention may be used inside a mobile vehicle, or carried by a person in a portable application. Further, theRouter200 may be provided as an external component connected to a portable device (e.g., a laptop computer) or may be implemented within the portable device, such that the portable device and theRouter200 are provided as one integrated unit. Further, theRouter200 may be used in conjunction with, or integrated into measuring and testing equipment, and transmission equipment. Such a remote device may be needed for very remote monitoring applications, such as wildlife studies, etc., necessitating the use of multiple Networks.
• Referring now toFIG. 37, there is shown thesoftware architecture219 of theRouter200 in accordance with an embodiment of the present invention. The architecture is strictly layered in that data flows only vertically between adjacent layers. The definition of each layer will now be described.
• The Application layer consists of various processes that perform services directly related to the function(s) for which the device is defined. This includes such services as defining a device configuration, making decisions about which route to select for the transport of data and performing various diagnostic functions.
• The Presentation layer consists of a protocol-independent insulating layer between the applications and the lower-level networking functions. The Presentation layer implements a Berkley sockets compliant application programming interface (API).
• The Networking layer performs all processing related to handling the Internet Protocol (IP). The main function of the networking layer in this environment is the routing of data passed into the layer from either above or below back out through selected Network Interfaces to deliver that data to the intended destination. The relationship of destination and network interface is maintained by the Configuration Module and Routing Decision Module applications.
• The Data-Link layer provides logical Network Interfaces through which the Networking Layer may send and receive data. One or more of these Network Interfaces may be active at any time. At least one network interface must be active for the device to function properly. The main purpose of the Data-Link layer is to insulate the Networking layer from the details of the many link-level protocols used to transport data.
• The Device-Specific layer deals with the details of establishing and maintaining data communications through various types of communication devices such as radios, modems and data controllers. Each Device-Specific driver handles the vagaries of configuring and interfacing with various types of communication devices while presenting a uniform interface to the Data-Link layer.
• The Physical Interface layer handles the direct interface to external components. For example: A serial port driver may handle the sending and receiving of individual data bytes through a specific type of serial controller such as an Intel8250.
• A description of the functionality supported by various module blocks as presented inFIG. 37 will now be described.
• TheConfiguration Module222 is an Application layer module that allows a technician to maintain a database of device configuration information. A technician may access the Configuration Module via a diagnostic serial port. Another implementation may allow a technician to access the Configuration module through any of the defined Network Interfaces via a standard socket.
• The Routing Decision Module220 selects the preferred network interface through which outbound data is transmitted. This decision is based upon a variety of metrics including: Interface availability; Time of day; Type of service required; Interface priority and others. Examples of various routing metric schemes are presented later.
• The TCP/IP Socket Interface224 supports an Application Programming Interface (API) which, for example, conforms to the standard Berkley sockets paradigm. Its purpose is to shield the Application Layer from the details of the underlying networking protocols. It allows different network implementations to be employed without the applications being required to adapt.
• The TCP/IP Router/Gateway226 implements standard IP host support with the additional capability of being able to act as a gateway between multiple networks. IP datagrams received by this layer that are not destined for a local IP host address are forwarded through the network interface that is currently designated as the preferred route for the given destination address. It is possible that the management and selection of preferred routes is implemented by the Routing Decision Module220 in the Application layer.
• ThePPP Protocol Driver228 provides a network interface whose data-link protocol conforms to the Point-To-Point protocol standard. TheSLIP Protocol Driver230 provides a network interface whose data-link protocol conforms to the Serial-Line Internet Protocol de facto standard.Other protocol drivers230 may be implemented which provide Network Interfaces which support either existing protocols or future protocols. The intent is to convey that the underlying link-layer protocol is transparent to the upper and lower layers and that additional protocols may be easily supported.
• TheMDC Interface Driver234 provides device-specific support forMobile Data Controller54, as described above. TheCDPD Interface Driver236 provides device-specific support for a Cellular Digital Packet Data controller. Other device-specific drivers, e.g., Modem “X”Interface Driver238 may be implemented to support current or future devices.
• TheSerial Port Driver240 deals with the hardware aspects of asynchronous serial data communications such as manipulating a Serial I/O controller or other such external interface. Otherphysical layer drivers242 may be implemented which support different external interface devices either existing or in the future.
• Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein; rather, the invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims.
• For example, the router of the present invention may be included as an internal component of the mobile device, proving for an integrated mobile device. Optionally, the router may be implemented entirely as a software process running on, for example, a portable personal computer. In such an implementation, the internal slot(s) of the personal computer may be provided with network interface(s) and a software program may serve as the- router core. Further, data may be routed to the different networks at another level than at the packet level. For example, entire messages may be routed over various networks if such a configuration is required.

Claims (1)

1. A method of end-to end data communications where data is transported via incompatible transmission formats in a transparent manner between a remote device and a host communication network using a wireless communications link, said remote device and said wireless communications link being connected to a mobile data controller, said host communication network and said wireless communications link being interfaced by a network interface device logically residing on said host communication network as a protocol-appropriate communications controller, said method comprising the steps of:

converting data to be transported between said remote device and said host communication network, said converting step converting said transported data between a remote device transmission format utilized by said remote device and one of a plurality of digital and analog wireless link transmission formats utilized by said wireless communications link;

transporting said transported data over said wireless communications link in accordance with said one of said wireless link transmission formats;

receiving said transport data from said wireless communications link;

converting said transported data between said one of said wireless link transmission formats and a network interface format utilized by said network interface device, said one of said wireless link transmission formats and said host network format being incompatible;

further converting said transported data between said network interface format and a host network format utilized by said host communication network; and

forwarding said transported data to said host communication network in accordance with said host network format.

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