US20040162921A1 - SCSI enclosure services - Google Patents

Abstract

A method and system for a management station managing a plurality of routing devices within a fabric. In one embodiment, this management of routing devices comprising the fabric occurs in the Storage Area Network environment. Use is made of a protocol which already exists in a Storage Area Network environment, such as the Fibre Channel Protocol for SCSI (“FCP”), for managing routing devices within a fabric. Each routing device comprising the fabric is assigned a logical unit number, which, in one embodiment, is based on the domain identifiers of each routing device. Further, the routing device to which the management station is physically is also labeled as LUN 0, and serves as the logical fabric SCSI Enclosure Services controller unit. The fabric interacts with the management station as though the fabric were a logical fabric SCSI Enclosure Services device coupled to a plurality of logical fabric SCSI Enclosure Services units. The management station is thus able to obtain information about, and manage, any of the routing devices comprising the fabric.

Description

RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 09/510,541 filed Feb. 22, 2000, which application claims the benefit, under 35 USC § 119(e), of U.S. Provisional Application Serial No. 60/121,353, by Kha Sin Teow, et al, filed on Feb. 24, 1999, entitled “SCSI Enclosure Services,” which are incorporated herein by reference in their entirety.[0001]
TECHNICAL FIELD
• The present invention relates generally to the field of computer networks, and more particularly, to the management of storage networks.[0002]
BACKGROUND OF THE INVENTION
• As a result of continuous advances in technology, particularly in the area of computer networking, the last decade has seen an explosion in the volume of data that is being captured, processed, stored and manipulated in business environments. This data explosion has fueled an increase in demand for data storage capacity. The challenges presented by this increased demand for data storage further are amplified by the fact that it is not just the existence of data alone that provides value, but rather the manner in which the data is stored, accessed, and managed, that creates a competitive advantage.[0003]
• Increased reliance on applications ranging from business intelligence and decision support, data warehousing and data mining of large databases, disaster tolerance and recovery, enterprise software, and imaging and graphics have all contributed to this trend. In addition, the development of Internet-based business operations and electronic-commerce specifically has intensified the demand placed on data centers. Customer interactions over the Internet have increased operational focus on the performance, scalability, management and flexibility of systems that use-business-critical data. This dependence on data for fundamental business processes by employees, customers and suppliers has greatly increased the number of input and output (“I/O”) transactions required of computer storage systems and servers. Thus, it is important that data storage be viewed as a centralized, managed resource that is available and capable of expansion without sacrificing access or performance.[0004]
• Despite the increased attention and resources devoted to data storage requirements, the technical capabilities of data storage systems have not kept pace with increasing data management demands and with the advancements in other networking technologies. In the 1980s, the near ubiquity of personal computers (“PCs”), workstations and servers required broader connectivity, resulting in the development of local and wide area networks to support messaging between computer systems. The data used by computers and servers connected to local and wide area networks typically are located on computer storage systems and servers, which store, process and manipulate data. The adoption of high speed messaging technologies such as gigabit Ethernet and asynchronous transfer mode (“ATM”), increased local and wide area network transmission speeds by more than 1,000 times during the 1990s. However, storage-to-server data transmission speeds increased by less than ten times during this period, creating a bottleneck between the local or wide area network and business-critical storage systems and servers.[0005]
• One conventional solution with regard to data storage and retrieval is Network Attached Storage (“NAS”), which commonly utilizes a Network File System (“NFS”). As illustrated in FIG. 1, such a[0006]system100 includes ahost device105, afile server110, a Small Computer Systems Interface (“SCSI”) bus116 and a plurality ofstorage devices122,124,126 and130.Device130 further includes alogical controller unit131 andlogical units132 and134. A logical unit is a target-resident entity that implements a device model and executes SCSI commands originated by an initiator. An initiator is a device that initiates communication with, and transmits commands to other devices.
• [0007]Host device105 andfile server110 can be conventional personal computers from, for instance, IBM Corporation of Armonk, N.Y., or high-end computer workstations from, for instance, Sun Microsystems, Inc. of Palo Alto, Calif.Storage devices122,124,126 can include, for instance, IBM's Ultrastar 18LZX.Device130 can be a Redundant Array of Inexpensive Disks (“RAID”) system, such as a GigaRAID/AA from nStor Corporation of San Diego, Calif. with thelogical units132 and134 representing individual hard disks, such as Barracuda 18LP-18.2GB-ST318275LW/LC of Seagate of Scotts Valley, Calif.
• [0008]File server110 is coupled via SCSI bus116 tostorage devices122,124,126 and130. The SCSI standard was adopted as the open I/O interface standard for storage-to-server connections in the 1980s. Whenhost device105 attempts to access any of thesestorage devices122,124,126, or130,host device105 must access them viafile server110. In particular,host device105 must establish a connection103 withfile server110, and then retrieve information stored withinstorage devices130,122,124, and126 by communicating withfile server110. Such anNAS system100, however, is inherently inefficient becausehost device105 must access each device viafile server110. By requiring access tostorage devices130,122,124 and126 to be routed throughfile server110, bandwidth constraints directly related tofile server110 will exist. In addition, with such asystem100 dedicated to a specific application, thesystem100 is not scalable. There also is a single point of failure in that iffile server110 is not available, thehost device105 will not be able to access any of thestorage devices122,124,126 and130.
• An alternative Storage Area Network (“SAN”) architecture, which attempts to solve the limitations associated with NAS systems described above, is a fabric-based SAN. A fabric typically is constructed with one or more routing devices, such as switches, and each storage device (or group of storage devices, for example, in the case of a loop-based architecture) is coupled to the fabric. Generally, devices coupled to the fabric are capable of communicating with every other device coupled to the fabric. This eliminates the bottleneck created in NAS, where every device coupled to a[0009]file server110 has to be accessed via thatsingle file server110. Further, the scalability limitations of the NAS system also are avoided by fabric-based SANs. In addition, since every device does not have to be accessed via a single file server, there is no single point of failure in the fabric-based SANs.
• One implementation of a fabric-based SAN is Fibre Channel, which is an American National Standards Institute (“ANSI”) high-speed, high-performance storage-to-server and server-to-server interconnect protocol. This application relates to “Fibre Channel Protocol for SCSI (FCP), Rev 012, May 30, 1995” and “Fibre Channel Physical and Signaling Interface-3, Rev 9.4, Nov. 5, 1997,” both published by American National Standard for Information Technology, which are each incorporated herein by reference in their entirety.[0010]
• Since Fibre Channel can support large data block transfers at gigabit speeds, Fibre Channel is well suited for data transfers between storage systems and servers. Fibre Channel also supports multiple protocols such as SCSI and Internet Protocol (“IP”). Furthermore, Fibre Channel provides transmission reliability with guaranteed delivery and transmission distances of up to[0011]10 kilometers. Fibre Channel complements and supports advancements in local and wide area network technologies, such as gigabit Ethernet and ATM, which directly cannot effectively transfer large blocks of data.
• Fibre Channel-based SANS deliver centrally managed storage through high availability architectures, managing systems, and exploiting effective storage methodologies like RAID and mirroring. The Fibre Channel Protocol for SCSI (“FCP”) relies upon the Small Computer System Interface (“SCSI”) communication scheme to communicate between devices, which are coupled to the fabric. One version of SCSI on which FCP can rely is SCSI-3. By incorporating SCSI, a protocol already native to many devices, into the fabric-based scheme, Fibre Channel is able to provide high-performance (e.g. gigabit per second data delivery and gigabit per second backup and recovery), a highly available storage network, and continuous access during network expansion. In addition, such a system can provide continuous access during network repair.[0012]
• In order to optimize the use of a Fibre Channel-based SAN, the routing devices within the SAN's fabric need to be able to be managed in order to provide universal, seamless and easy access to storage resources. Conventional management techniques require use of multiple protocols. For instance, in an IP network, the Simple Network Management Protocol (“SNMP”) is used to manage the network. However, SNMP requires the Internet Protocol (“IP”), which is not commonly available in a SAN storage device. Therefore it is highly desirable to use the same FCP protocol for managing the routing devices within the fabric-based SAN as well as for communicating with the devices coupled to the fabric. This approach will eliminate the need for a multi-protocol system, as well as create more flexibility in the choice of management systems available.[0013]
• Accordingly, a need exists for managing routing devices within a fabric, based on a protocol that already exists within a fabric-based SAN.[0014]
SUMMARY OF THE INVENTION
• In accordance with the system and method of the present invention, routing devices within a fabric are managed using a native protocol that exists within a fabric-based SAN. Through such a management scheme, a management station can manage the fabric by treating the fabric as a logical fabric SES device. In one embodiment of the present invention, a plurality of routing devices within the fabric are recharacterized as logical units, which are included within the logical fabric SES device. In such a management scheme, the management station interacts with the logical fabric SES device as if the logical fabric SES device includes a smart controller and multiple logical units, each with a separate logical unit number. The management station then can perform management functions, such as configuration (e.g., enable or disable a routing device port) and performance evaluation (e.g., monitor temperature sensor readings of a routing device or monitor the performance or error counters of a routing device port) on any routing device within the fabric.[0015]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 illustrates a high level block diagram of a conventional Network Attached Storage system.[0016]
• FIG. 2A illustrates a high level block diagram of a fabric-based Storage Area Network system of an embodiment of the present invention.[0017]
• FIG. 2B illustrates a flowchart of the steps performed by a first device for communicating with a second device coupled to the fabric of an embodiment of the present invention.[0018]
• FIG. 3 illustrates a more detailed block diagram of the fabric of an embodiment of the present invention.[0019]
• FIG. 4 illustrates a more detailed block diagram of a routing device within the fabric of an embodiment of the present invention.[0020]
• FIG. 5A illustrates a domain identifier to logical unit number mapping table of an embodiment of the present invention.[0021]
• FIG. 5B illustrates a flowchart of the steps performed in assigning a logical unit number to a routing device of an embodiment of the present invention.[0022]
• FIG. 6A illustrates a logical (fabric) SCSI Enclosure Services device of an embodiment of the present invention.[0023]
• FIG. 6B illustrates a flowchart depicting the steps performed by a management station in communicating with a routing device within the fabric, of an embodiment of the present invention.[0024]
DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION
• Embodiments of the present invention are now described with reference to figures where like reference numbers indicate identical or functionally similar elements and the left most digit(s) of each reference number corresponds to the figure in which the reference number is first used.[0025]
• The following discussion will focus upon Fibre Channel-based SANS, and how routing devices within the fabric in a Fibre Channel based SAN are recharacterized as Logical Units. However, one skilled in the art will recognize that the present invention may be applied to any network topology or protocol, which utilizes a fabric.[0026]
• FIG. 2A illustrates a Fibre Channel fabric-based[0027]SAN200 of an embodiment of the present invention.SAN200 includes afabric210 andhost device205,storage devices222,224,226 and230 and aloop220.Storage device230 further includeslogical controller unit231 andlogical units232 and234.Loop220 is an arbitrated loop with a shared bandwidth forstorage devices222,223 and226, which are coupled toloop220.Host device205 can be a conventional computer, such as a personal computer, or an IBM RS6000 or a Sun Ultra 30 Workstation.Device230 can be a RAID system, such as a Clariion 5600C from EMC of Hopkinton, Mass.Device230 includeslogical units232 and234, as well as alogical controller231.
• [0028]Fabric210 seamlessly coupleshost device205 todevice230, and tostorage devices222,224, and226 vialoop220. Thus, a host device, such ashost device205, which is coupled tofabric210 can communicate overfabric210 to any other device, such asdevice230, regardless of the composition offabric210. If, however, thefabric210, in an alternative embodiment, is divided into zones, thenhost device205 only would be able to access and manage those devices that are within the same zone ashost device205.
• If[0029]host device205 intends upon communicating with a storage device (e.g., device230), which is coupled to thefabric210,host device205 would be considered an “initiator.” An initiator is a device that initiates communication with, and transmits commands to other devices.Storage device230 would be considered a “target” becausestorage device230 would receive instructions from an initiator such ashost device205, and would execute those instructions.
• FIG. 2B illustrates a flowchart of the steps for initiating FCP communication between devices that are attached to a[0030]fabric210 of an embodiment of the present invention. A device, such as205, logs intofabric210 by performing a Fabric Login (“FLOGI”)250. During this step, thefabric210 assigns a Fibre Channel well-known address to the initiator device, which in this case ishost device205. Next, thehost device205 performs a Port Login (“PLOGI”)252 with the name server. Thehost device205 communicates with the name server by transmitting the well-known address (e.g., FFFFFCh) of the name server. In one embodiment, the name server can reside within thefabric210 and can maintain registered information for each of the devices coupled to thefabric210. One skilled in the art will recognize that in an alternative embodiment, the name server can reside outside thefabric210.
• [0031]Host device205 transmits253 a request to the name server to obtain a list of the devices coupled to thefabric210.Host205 receives254 a response from the name server, which includes information regarding the addresses of thevarious storage devices222,224,226, and230, that are coupled tofabric210.Host device205 utilizes this address information to make adetermination255 regarding with which of thestorage devices222,224,226, or230 to communicate. Once this target storage device, e.g.230, has been chosen255,host device205 performs aPLOGI256 with thattarget storage device230. As previously discussed,target storage device230 includes alogical controller unit231, andlogical units232 and234.Host device205, therefore, performsPLOGI256 withlogical controller unit231 to establish contact, withtarget storage device230.Host device205 then performs a Process Login (“PRLI”)258 withlogical controller unit231 to determine the capabilities oftarget storage device230, as to whetherhost device205 andtarget storage device230 can communicate with each other using FCP. Upon establishing thathost device205 andtarget storage device230 can communicate with each other,host device205 optionally transmits260 a “Report LUNs” command to thelogical controller unit231. This command results inhost device205 receiving from logical controller unit231 a list of all of the LUNs withinstorage device230.Host device205 utilizes this list of LUNs to determine264 with which logicalunit host device205 will communicate. Upon selecting a LUN,host device205 may communicate260 with the chosen logical unit, (e.g., logical unit232). Ifhost device205 had initially chosen255 to communicate with a different storage device, such asstorage device222, which unlikestorage device230 does not include logical units, then PLOGI256 andPRLI258 would have been performed directly withtarget storage device222, and step268 would have been performed directly afterstep258.Steps260,262, and264 would not have been performed at all.
• FIG. 3 illustrates a more detailed block diagram of the[0032]fabric210 of an embodiment of the present invention.Fabric210 includesseveral routing devices302,304, and306 which are connected with each other.Routing devices302,304, and306 can be any type of networking device including switches, hubs or routers. In order to manage these routing devices, information about and the ability to manage theserouting devices302,304, and306 is needed to be able to optimally configure thefabric210.
• To manage these[0033]routing devices302,304, and306, an analogous method to the method described with regard to FIG. 2A can be used byhost device205. Sincehost device205 will now have the capability of managingrouting devices302,304, and306, for the remainder of this discussion,host device205 will be called a “management station.”
• A[0034]system200 in accordance with an embodiment of the present invention manages therouting devices302,304, and306 within thefabric210, by using the Fibre Channel Protocol for SCSI (“FCP), which already is used in communicating withstorage devices222,224,226 and230. In one embodiment, FCP can be based on SCSI-3. Themanagement station205 within this system utilizes FCP to facilitate its communication withrouting devices302,304, and306. In one embodiment, themanagement station205 is connected via a Fibre Channel link to at least one of therouting devices302 within thefabric210 and communicates with and manages any of therouting devices302,304, and306. In such an embodiment, themanagement station205 recognizes thefabric210 as an FCP target with a well-known address (e.g., FFFFFAh). Thefabric210, therefore, will now be treated like a SCSI logical controller with multiple logical units. In one embodiment of the present invention, therouting devices302,304, and306 are managed based upon industry-standard SCSI Enclosure Services (“SES”) commands. One skilled in the art will understand that SES is a subset of the FCP command set for storage device management purpose. “SCSI Enclosure Services (SES) Command Set, Rev 8a, Jan. 16, 1997” published by American National Standard for Information Technology is incorporated herein by reference in its entirety.
• FIG. 4 illustrates a more detailed block diagram of[0035]routing device302 of an embodiment of the present invention. Therouting device302 includes anSES management server400, which is used for managingrouting device302. TheSES management server400 includes alogical unit generator410, a configuration server420, and amanager430. In one embodiment, themanager410 supports SES commands. The configuration server420 obtains information regarding the topology and composition of thefabric210, and thelogical unit generator410 utilizes this information to assign a unique logical unit number (“LUN”) to eachrouting device302,304, and306 within thefabric210. Subsequent to this assignment of LUNs to eachrouting device302,304,306, themanager430 communicates with themanagement station205. Themanagement station205 now can communicate with thefabric210 as though thefabric210 were a logicalfabric SES device610, which includes multiple logicalfabric SES units602,604,606. Within this scheme, themanagement station205 can access and communicate with all of theserouting devices302,304, and306 in a manner analogous tomanagement station205 accessing and communicating withlogical units232 and234 as described with regard to FIG. 2B. One skilled in the art will recognize that in one embodiment, thelogical unit generator410, the configuration server420, and themanager430, are software modules. In an alternative embodiment, these modules can be implemented in hardware. In still another alternative embodiment, these modules can be implemented as a combination of hardware and software.
• FIG. 5A illustrates a domain identifier to LUN mapping table that can be included in the[0036]logical unit generator410 in one embodiment of the present invention. The domain identifier (“Domain-ID”) for each routing device within the fabric is obtained by configuration server420. Thelogical unit generator410 retrieves this topological information from the configuration server420 and maps these Domain-IDs to LUNs within the LUN mapping table. In particular, thelogical unit generator410 maps the Domain-ID to a unique LUN value, which is illustrated as a hexadecimal value. In one embodiment, for all logical units except LUN 0 (e.g., 00000000 00000000), byte one of the LUN value in hexadecimal is set using the Domain-ID of the routing device, and bytes2 through7 are set to zero.
• FIG. 5B illustrates a flowchart of the steps performed by the[0037]SES management server400 in assigning a LUN value to eachrouting device302,304, or306 of an embodiment of the present invention. The Domain-ID of a routing device is identified550. A LUN value is created552 based upon the Domain-ID. This LUN value then is assigned554 to the corresponding routing device.
• Regardless of the specific manner in which the LUNs are assigned to the[0038]routing devices302,304, and306, therouting device302 to which themanagement station205 is physically connected, functions as the logical fabricSES controller unit602a.In one embodiment, the logical fabricSES controller unit602ais identified asLUN 0. By identifying therouting device302 in thefabric210 to which themanagement station205 is physically connected as a logical fabric.SES controller unit602a,the logical fabricSES controller unit602ais ensured to be present in thefabric210. Thus, themanagement station205 will communicate directly with logical fabricSES controller unit602ain order to obtain information regarding therouting devices302,304 and306 coupled to thefabric210.
• The[0039]routing device302 to which themanagement station205 is physically connected, is also assigned a LUN based upon the same algorithm used for assigning LUNs to routingdevices304, and306. Hence, there are two logical fabric SES units corresponding to therouting device302, which is physically connected to management station205: a logical fabricSES controller unit602awhich is identified asLUN 0, and a logicalfabric SES unit602b,which is assigned a LUN in a similar manner as theother routing devices304, and306.
• FIG. 6A illustrates a logical[0040]fabric SES device610 of an embodiment of the present invention. As described above, eachrouting device302,304, and306 within thefabric210 is assigned a LUN. By assigning a LUN to eachrouting device302,304, and306,routing devices302,304 and306 are recharacterized as alogical controller602aand logicalfabric SES units602b,604, and606. Hence, thefabric210 now functions like a logicalfabric SES device610. Thus,management station205 interacts with the logicalfabric SES units602b,604, and606, which correspond to routingdevices302,304, and306, respectively, in a similar manner ashost device205 interacted withdevice230,logical units232 and234, and thelogical controller unit231, as discussed with regard to FIG. 2A. Through this reconfiguration of thefabric210, themanagement station205 now can manage therouting devices302,304, and306 within thefabric210. In addition, if more routing devices were added to thefabric210, theSES management server400 would automatically compensate accordingly by proceeding through thesame steps550,552 and554 to assign a LUN to the newly added routing device.
• FIG. 6B illustrates a flowchart depicting the steps for managing the[0041]routing devices302,304, and306 withinfabric210. Themanagement station205 performs a Fabric Login (“FLOGI”)650 in order to obtain a well-known address from thefabric210. Themanagement station205 performs a Port Login (“PLOGI”)656 with theSES management server400. The PLOGI step includes transmitting the well-known address (e.g., FFFFFAh) corresponding to theSES management server400. ThePLOGI656 with theSES management server400 establishes a link between themanagement station205 and the logicalfabric SES device610.
• The[0042]management station205 then determines657 whether the Process Login (“PRLI”)5 step is to be performed with theSES management server400. If PRLI needs to be performed,PRLI658 is initiated to determine the capabilities of the logical fabricSES controller unit602a.In one embodiment of the present invention, the PRLI step is optional. If PRLI does not need to be performed,step660 is performed directly afterstep657. Instep660, themanagement station205 would transmit a “Report LUNs” command to the logical fabricSES controller unit602a.If themanagement station205 does not perform PRLI, themanagement station205 will transmit660 a “Report LUNs” command to the logical fabricSES controller unit602a.The “Report LUNs” command results in the logical fabricSES controller unit602areturning662 a list of all the LUNs comprising the logicalfabric SES device610 to themanagement station205.
• The[0043]management station205 determines664 which routing device (e.g.304) to obtain information from and manage. Themanagement station205 transmits666 a “Receive Diagnostic Results” command to the LUN corresponding to a routing device (e.g.404) for which themanagement station205 has determined information is desired.
• Upon receiving this command, the specified logical[0044]fabric SES unit610 returns668 diagnostic or management data to themanagement station205. Based on this diagnostic data, themanagement station205 can proceed to manage therouting device304 by issuing670 further management commands to the corresponding logicalfabric SES unit604. For example, themanagement station205 can perform a configuration, performance, and/or enclosure function on a routing device. Themanagement station205 can enable or disable a port on a specific routing device, take the temperature sensor readings of a routing device, or monitor the performance or error counters of a port on a specific routing device.
• More specifically, the[0045]management station205 can issue standard SCSI commands to routingdevices302,304, and306. For instance, themanagement station205 can transmit a command to receive the “Switch Page,” which will permit themanagement station205 to obtain status information about a routing device (e.g.304), its operational state and firmware as well as information about the boot date and time and the last date and time the firmware was updated. Similarly, the “Fabric Page” command allows themanagement station205 to obtain information about thefabric210, including what neighbors thefabric210 has. Another example is the “Sensor Table Page” command, which provides the status of all sensors in arouting device304. One skilled in the art will recognize that any other SCSI commands can be used by themanagement station205 to obtain information regarding thefabric210.
• From the above description, it will be apparent to one skilled in the art that the present invention disclosed herein provides a novel and advantageous method and system for managing routing devices coupled within a fabric. The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. As will be understood by those familiar with the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.[0046]

Claims (27)

1. A logical fabric SCSI Enclosure Services device comprising:

a logical fabric SCSI Enclosure Services controller unit; and

a first logical fabric SCSI Enclosure Services unit coupled to the logical fabric SCSI Enclosure Services controller unit.

2. The logical fabric SCSI Enclosure Services device ofclaim 1, further comprising a second logical fabric SCSI Enclosure Services unit.

3. The logical fabric SCSI Enclosure Services device ofclaim 1, wherein the first logical fabric SCSI Enclosure Services unit corresponds to a routing device.

4. The logical fabric SCSI Enclosure Services device ofclaim 3, wherein the routing device is a switch,

5. The logical fabric SCSI Enclosure Services device ofclaim 1, wherein the first logical fabric SCSI Enclosure Services unit includes a logical unit number.

6. The logical fabric SCSI Enclosure Services device ofclaim 5, wherein the first logical fabric SCSI Enclosure Services unit corresponds to a domain identifier, that is used to assign a logical unit number.

7. The system ofclaim 1, wherein the fabric is a Fibre Channel fabric.

8. A system for managing routing devices within a fabric, the system comprising:

a logical fabric SCSI Enclosure Services device; and

a management station coupled to the logical fabric SCSI Enclosure Services device.

9. The system ofclaim 8, wherein the logical fabric SCSI Enclosure Services device comprises:

a logical fabric SCSI Enclosure Services controller unit; and

a logical fabric SCSI Enclosure Services unit coupled to the logical fabric SCSI Enclosure Services controller unit.

10. The system ofclaim 9, wherein the logical fabric SCSI Enclosure Services controller unit corresponds to a routing device physically connected to the management station.

11. The system ofclaim 9, wherein the logical fabric SCSI Enclosure Services unit is a Fibre Channel Protocol for SCSI (FCP) unit.

12. The system ofclaim 9, wherein the fabric is a Fibre Channel fabric.

13. A SCSI Enclosure Services management server comprising:

a configuration server; and

a logical unit generator adapted to receive information from the configuration server and to recharacterize a routing device as a logical fabric SCSI Enclosure Services unit.

14. The SCSI Enclosure Services management server ofclaim 13 further comprising:

a manager adapted to manage the routing device recharacterized as a logical fabric SCSI Enclosure Services unit.

15. A method for managing a plurality of routing devices within a fabric, the method comprising the steps of:

assigning each of the plurality of routing devices a logical unit number.

16. The method ofclaim 15, wherein the assigning step comprises assigning each of the plurality of routing devices a logical unit number based upon a corresponding domain identifier.

17. The method ofclaim 15, further comprising the step of:

assigning a routing device a logical unit number of zero if the routing device is physically connected to a management station.

18. A method for assigning logical unit numbers to a network of interconnected routing devices, the method comprising:

specifying a unique identification for one of the plurality of routing devices;

creating a logical unit number for the routing device based upon the unique identification; and

assigning the logical unit number to the routing device.

19. The method ofclaim 18, wherein the unique identification for a routing device is a domain identifier.

20. An electronically readable medium storing a program for permitting a computer to perform a method for managing a plurality of routing devices within a fabric, the method comprising:

assigning each of the plurality of routing devices a logical unit number.

21. An electronically readable medium storing a program for permitting a computer to perform a method for assigning logical unit numbers to a plurality of routing devices, the method comprising:

specifying a unique identifier for one of the plurality of routing devices;

creating a logical unit number for the routing device based upon the unique identifier; and

assigning the created logical unit number to the routing device.

22. The electronically readable medium ofclaim 21, wherein the unique identifier for one of the plurality of routing devices is a domain identifier.

23. A network routing device for use in a fabric, the routing device comprising:

a logical fabric SCSI Enclosure Services controller unit; and

a logical fabric SCSI Enclosure Services unit coupled to said logical fabric SCSI Enclosure Services controller unit.

24. The routing device ofclaim 23, wherein the routing device is a switch.

25. The routing device ofclaim 23, wherein said logical fabric SCSI Enclosure Services controller unit includes a logical unit number and said logical fabric SCSI Enclosure Services unit includes a logical unit number different from that of said logical fabric SCSI Enclosure Services controller unit.

26. The routing device ofclaim 25, wherein said logical fabric SCSI Enclosure Services unit logical unit number corresponds to a domain identifier of the routing device.

27. The routing device ofclaim 23, further comprising:

a SCSI Enclosure Services management server.

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