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PROPOSED STANDARD
Network Working Group                                        A. SiddiquiRequest for Comments: 4710                                  D. RomascanuCategory: Standards Track                                          Avaya                                                           E. Golovinsky                                                             Alert Logic                                                            October 2006Real-time Application Quality-of-ServiceMonitoring (RAQMON) FrameworkStatus of This Memo   This document specifies an Internet standards track protocol for the   Internet community, and requests discussion and suggestions for   improvements.  Please refer to the current edition of the "Internet   Official Protocol Standards" (STD 1) for the standardization state   and status of this protocol.  Distribution of this memo is unlimited.Copyright Notice   Copyright (C) The Internet Society (2006).Abstract   There is a need to monitor end-devices such as IP phones, pagers,   Instant Messaging clients, mobile phones, and various other handheld   computing devices.  This memo extends the remote network monitoring   (RMON) family of specifications to allow real-time quality-of-service   (QoS) monitoring of various applications that run on these devices   and allows this information to be integrated with the RMON family   using the Simple Network Management Protocol (SNMP).  This memo   defines the framework, architecture, relevant metrics, and transport   requirements for real-time QoS monitoring of applications.Table of Contents1. Introduction ....................................................22. RAQMON Functional Architecture ..................................43. RAQMON Operation in Congestion-Safe Mode .......................114. Measurement Methodology ........................................145. Metrics Pre-Defined for the BASIC Part of the RAQMON PDU .......146. Report Aggregation and Statistical Data processing .............287. Keeping Historical Data and Storage ............................298. Security Considerations ........................................309. Acknowledgements ...............................................3210. Normative References ..........................................3311. Informative References ........................................34Siddiqui, et al.            Standards Track                     [Page 1]

RFC 4710                    RAQMON Framework                October 20061.  Introduction   With the growth of the Internet and advancements in embedded   technologies, smart IP devices (such as IP phones, pagers, instant   message clients, mobile phones, wireless handhelds, and various other   computing devices) have become an integral part of our day-to-day   operations.  Enterprise operators, information technology (IT)   managers, application service providers, network service providers,   and so on, need to monitor these application and device types in   order to ensure that end user quality-of-service (QoS) objectives are   met.  This memo describes a monitoring solution for these   environments, extending the remote network monitoring (RMON) family   of specifications [RFC2819].  These extensions support real-time QoS   monitoring of typical applications that run on end-devices mentioned   above, and they allow this information to be integrated using the   familiar RMON family of specifications via SNMP [RFC3416].   The Real-time Application QoS Monitoring Framework (RAQMON) allows   end-devices and applications to report QoS statistics in real time.   Many real-time applications (as well as non-real-time applications   managed within the RMON family of specifications) can report   application-level QoS statistics in real time using the RAQMON   Framework outlined in this memo.  Some possible applications   scenarios include applications such as Voice over IP, Fax over IP,   Video over IP, Instant Messaging (IM), Email, software download   applications, e-business style transactions, web access from handheld   computing devices, etc.   The user experience of an application running on an IP end-device   depends upon the type of application the user is running and the   surrounding resources available to that application.  An end-to-end   application QoS experience is a compound effect of various   application-level transactions and available network and host   resources.  For example, the end-to-end user experience of a Voice   over IP (VoIP) call depends on the total time required to set up the   call as much as on media-related performance parameters such as end-   to-end network delay, jitter, packet loss, and the type of codec used   in a call.  The performance of a VoIP call is also influenced by   behavior of network protocols like the Reservation Protocol (RSVP),   explicit tags in differentiated services (DiffServ) [RFC2475] or IEEE   802.1 [IEEE802.1D] along with available host resources such as device   CPU or memory utilized by other applications while the call is   ongoing.   The end-to-end application quality of service (QoS) experience is   application context sensitive.  For example, the kinds of parameters   reported by an IP telephony application may not really be needed for   other applications such as Instant Messaging.  The RAQMON FrameworkSiddiqui, et al.            Standards Track                     [Page 2]

RFC 4710                    RAQMON Framework                October 2006   offers a mechanism to report the end-to-end QoS experience   appropriate for a specific application context by providing   mechanisms to report a subset of metrics from a pre-defined list.   In order to facilitate a complete end-to-end view, RAQMON correlates   statistics that involve:      i.   "User, Application, Session"-specific parameters (e.g.,            session setup time, session duration parameters based on            application context).      ii.  "IP end-device"-specific parameters during a session (e.g.,            CPU usage, memory usage).      iii. "Transport network"-specific parameters during a session            (e.g., end-to-end delay, one-way delay, jitter, packet loss            etc).   At any given point, the applications at these devices can correlate   such diverse data and report end-to-end performance.  The RAQMON   Framework specified in this memo offers a mechanism to report such   end-to-end QoS view and integrate such a view into the RMON family of   specifications.  In particular, the RAQMON Framework specifies the   following:      a. A set of basic metrics sent as reports between the RAQMON         entities using for transport existing Internet Protocols such         as TCP or SNMP.      b. Requirements to be met by the underlying transport protocols         that carry the RAQMON reports.      c. A portion of the Management Information Base (MIB) as an         extension of the RMON MIB Modules for use with network         management protocols in the Internet community.   This memo provides the RAQMON functional architecture, RAQMON entity   definitions and requirements, requirements for the transport   protocols, a set of metrics, and an information model for the RAQMON   reports.   Supplementary memos will describe the mapping of the basic RAQMON   metrics onto different transport protocols.  For example, the RAQMON   PDU [RFC4712] memo provides definitions of syntactical PDU structure   and use case scenarios of transmission of such PDUs over the   Transmission Control Protocol (TCP) and the Simple Network Management   Protocol (SNMP).Siddiqui, et al.            Standards Track                     [Page 3]

RFC 4710                    RAQMON Framework                October 2006   The RAQMON MIB [RFC4711] memo describes the Management Information   Base (MIB) for use with the SNMP protocol in the Internet community.   The document proposes an extension to the Remote Monitoring MIB   [RFC2819] to accommodate RAQMON solutions.   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this   document are to be interpreted as described in [RFC2119].2.  RAQMON Functional Architecture   The RAQMON Framework extends the architecture created in the RMON MIB   [RFC2819] by providing application performance information as   experienced by end-users.  The RAQMON architecture is based on three   functional components named below:      -  RAQMON Data Source (RDS)      -  RAQMON Report Collector (RRC)      -  RAQMON MIB Structure   A RAQMON Data Source (RDS) is a functional component that acts as a   source of data for monitoring purposes.  End-devices like IP phones,   cell phones, and pagers, and application clients like instant   messaging clients, soft phones in PCs, etc., are envisioned to act as   RDSs within the RAQMON Framework.Siddiqui, et al.            Standards Track                     [Page 4]

RFC 4710                    RAQMON Framework                October 2006   +----------------------+        +---------------------------+   |    IP End-Device     |        |    IP End-Device   >----+ |   |+--------------------+|        |+--------------------+   | |   || APPLICATION        ||        || APPLICATION        |   | |   ||  -Voice over IP   <----(1)----> -Voice over IP    >- + | |   ||  -Instant Messaging||        ||  -Instant Messaging| | 3 |   ||  -Email            ||        ||  -Email            | 2 | |   |+--------------------+|        |+--------------------+ | | |   |                      |        |                       | | |   |                      |        | +------------------+  | | |   +----------------------+        | |RAQMON Data Source|<-+ | |                                   | |    (RDS)         |<---+ |                                   | +------------------+      |                                   +-----------|---------------+                                               |                                 (4) RAQMON PDU transported                               over TCP or SNMP Notifications                                               |                  +----------------------------+                  |                            |                  |/                           |/     +------------------+      +------------------+       +------------+     |RAQMON Report     |  ..  |RAQMON Report     |       | Management |     |Collector (RRC) #n|      |Collector (RRC) #1|<--5-->| Application|     +------------------+      +------------------+       +------------+                       Figure 1 - RAQMON Framework.      (1) Communication Session between real-time applications      (2) Context-Sensitive Metrics      (3) Device State Specific Metrics      (4) Reporting session - RAQMON metrics transmitted over  specified          interfaces (Specific Protocol Interface, IP Address, port)      (5) Management Application - RRC interaction using the RAQMON MIB   A RAQMON Report Collector (RRC) collects statistics from multiple   RDSs, analyzes them, and stores such information appropriately.  RRC   is envisioned to be a network server, serving an administrative   domain defined by the network administrator.  The RRC component of   the RAQMON architecture is envisioned to be computationally   resourceful.  Only RRCs should implement the RAQMON MIB module.Siddiqui, et al.            Standards Track                     [Page 5]

RFC 4710                    RAQMON Framework                October 2006   The RAQMON Management Information Base (RAQMON MIB) extends the   Remote Monitoring MIB [RFC2819] to accommodate the RAQMON Framework   and exposes End-to-End Application QoS information to Network   Management Applications.2.1.  RAQMON Data Source (RDS)2.1.1.  RAQMON Data Source (RDS) Functional Architecture   A RAQMON Data Source (RDS) is a source of data for monitoring   purposes.  The RDS monitoring function is performed in real time   during communication sessions.  The RDS entities capture QoS   attributes of such communication sessions and report them within a   RAQMON "reporting session".   An RDS is primarily responsible for abstracting IP end-devices and   applications within the RAQMON architecture.  It gathers the   parameters for a particular communication session and forwards them   to the appropriate RAQMON Report Collector (RRC).  Since it is   envisioned that the RDS functionality will be realized by writing   firmware/software running on potentially small, low-powered end-   devices, the design of the RDS element is optimized towards that end.   Like the implementations of routing and management protocols, an   implementation of RDS in an end-device will typically execute in the   background, not in the data-forwarding path.   RDSs use a PUSH mechanism to report QoS parameters.  While the   applications running on the RDS decide about the content of the PDU   appropriate for an application context, an RDS asynchronously sends   out reports to RRC.   The rate at which PDUs are sent from RDSs to RRCs is controlled by   the applications' administrative domain policy.  While this mechanism   provides flexibility to gather a detailed end-to-end experience   required by IT managers and system administrators, certain steps   should be followed to operate RAQMON in congestion-safe manner.Section 3 addresses steps required for congestion-safe operation.   An RDS reports QoS statistics for simplex flows.  At a given   instance, a report from RDS is logically viewed as a collection of   QoS parameters associated with a communication session as perceived   by the reporting RDS.  For example, if two IP phone users, Alice and   John, are involved in a communication session, the end-to-end delay   experienced by the IP phone user Alice could be different from the   one experienced by the IP phone user John for a variety of reasons.   Hence, a report from Alice's IP phone represents the QoS performance   of that call as perceived by the RDS that resides in Alice's IP   phone.Siddiqui, et al.            Standards Track                     [Page 6]

RFC 4710                    RAQMON Framework                October 20062.1.2.  RAQMON Data Source (RDS) Requirements      1. RAQMON Data Sources SHALL gather reports from multiple         applications residing in that device and SHALL send out         compound QoS reports associated with multiple communication         sessions at a given moment.         Examples include a conference bridge hosting several different         conference calls or a two-party video call consisting of         audio/video sessions.  In each case an RDS could send out one         single RAQMON report that consists of multiple sub-reports         associated with audio and video sessions or sub-reports for         each conference call.      2. RAQMON Data Sources MUST implement the TCP transport and MAY         implement the SNMP transport.2.1.3.  Configuring RAQMON Data Sources   In order to report statistics to RAQMON Report Collectors, RDSs will   need to be configured with the following parameters:      1. The time interval between RAQMON PDUs.  This parameter MUST be         configured such that overflow of any RAQMON parameter within a         PDU between consecutive transmissions is avoided.      2. The IP address and port of target RRC.   An RDS may use manual configuration for the RDS configuration   parameters using command line interface (CLI), Telephone User   Interface (TUI), etc.   One of the following mechanisms to gain access to configuration   parameters can also be considered:      -  RDS acts as a trivial file transfer protocol (TFTP) client and         downloads text scripts to read the parameters.      -  RDS acts as a Dynamic Host Configuration Protocol (DHCP) Client         and gets RRC addressing information as a DHCP option.      -  RDS acts as a DNS client and gets target collector information         from a DNS Server.      -  RDS acts as a LDAP Client and uses directory look-ups.   Identifying the DHCP option and structure to use, defining the   structure of the configuration information in DNS, or defining a LDAP   schema could be explored as items of future work.Siddiqui, et al.            Standards Track                     [Page 7]

RFC 4710                    RAQMON Framework                October 2006   Compliance to the RAQMON specification does not require usage of any   specific configuration mechanisms mentioned above.  It is left to the   implementers to choose appropriate provisioning mechanisms for a   system.2.2.  RAQMON Report Collector (RRC)2.2.1.  RAQMON Report Collector (RRC) Functional Architecture   A RAQMON Report Collector (RRC) receives RAQMON PDUs from multiple   RDSs and analyzes and stores the information in the RAQMON MIB.  The   RRC is envisioned to be computationally resourceful, providing a   storage and aggregation point for a set of RDSs.   Since RDSs can belong to separate administrative domains, the RAQMON   Framework allows RDSs to report QoS parameters to separate RRCs.   Vendors can develop a management application to correlate information   residing in different RRCs across multiple administrative domains to   represent one communication session.  However, such an application-   level specification is beyond the scope of this memo.2.2.2.  RAQMON Report Collector (RRC) Requirements      1. RAQMON Report Collectors MUST support the mandatory mapping         over TCP of the RAQMON information model defined in [RFC4712]         with the purpose of receiving RAQMON reports from RAQMON Data         Sources (RDS).      2. RAQMON Report Collectors MAY support the optional mapping over         SNMP notifications of the RAQMON information model defined in         [RFC4712].      3. RAQMON Report Collectors MUST implement session timeout         mechanisms to assume end of reporting for RDSs that have been         out of reporting for a reasonable duration of time.  Such         timeout parameters SHOULD be configurable in vendor         implementations, as programmable parameters at deployment.      4. RAQMON Report Collectors MUST support the RAQMON-MIB module and         meet the compliance requirements of the raqmonCompliance         MODULE-COMPLIANCE definition as described in [RFC4711].  The         population of the RAQMON MIB with performance monitoring         information is independent of the transport protocol, or         protocols used to carry the information between RDSs and RRCs.Siddiqui, et al.            Standards Track                     [Page 8]

RFC 4710                    RAQMON Framework                October 20062.3.  Information Model and RAQMON Protocol Data Unit (PDU)2.3.1.  RAQMON Information Model   RAQMON defines a set of basic metrics that characterize the QoS of   applications, as reported by RAQMON Data Sources.  This basic set of   metrics is defined inSection 5 of this memo.  There is no minimal   requirement for a mandatory set of metrics to be supported by an RDS.   Specific applications, new types of network appliances or new methods   to measure and characterize the QoS of applications lead to the   requirement for the information model to be extensible.  To answer   this need, the information model is designed so that vendors can   extend it by adding new metrics.   Although NOT REQUIRED for RAQMON conformance, extensions of the   information model can offer useful information for specific   applications.  An example of metrics that can extend the basic RAQMON   information model are the detailed metrics for VoIP media monitoring   and call quality included in the VoIP Metrics Report Block defined in   [RFC3611].   The RAQMON Information model is expressed by defining a conceptual   RAQMON Protocol Data Unit (PDU).2.3.2.  RAQMON Protocol Data Unit   A RAQMON Protocol Data Unit (PDU) is a common data format understood   by RDSs and RRCs.  A RAQMON PDU does not transport application data   but rather occupies the place of a payload specification at the   application layer of the protocol stack.  Different transport   mappings may be used to carry RAQMON PDU between RDSs and RRCs.   Transport protocol requirements are being defined inSection 2.4 of   this memo.   Though architected conceptually as a single PDU, the RAQMON PDU is   functionally divided into two different parts.  They are the BASIC   part, and the Application-Specific Extensions, required for   application-, vendor-, and device-specific extensions.   The BASIC part of the RAQMON PDU:      The BASIC part of the RAQMON PDU follows the SMI Network      Management Private Enterprise Code 0, indicating an IETF standard      construct.  The RAQMON PDU BASIC part offers an entry-type from a      pre-defined list of QoS parameters defined inSection 5 and allows      applications to fill in appropriate values for those parameters.      Application developers also have the flexibility to make an RDS      report built only of a subset of the parameters listed inSiddiqui, et al.            Standards Track                     [Page 9]

RFC 4710                    RAQMON Framework                October 2006Section 5.  There is no need to carry all metrics in every PDU;      moreover, it is RECOMMENDED that static or pseudo-static metrics      that do not change or seldom change for a given session or      application will be send only when the session or application are      initiated, and then at large time intervals.   The Application part of RAQMON PDU:      Since it is difficult to structure a BASIC part that meets the      needs of all applications, RAQMON provides extension capabilities      to convey application-, vendor-, and device-specific parameters      for future use.  Additional parameters can be defined within      payload of the APP part of the PDU by the application developers      or vendors.  The owner of the definition of the application part      of the RAQMON PDU is indicated by a vendor's SMI Network      Management Private Enterprise Code defined inhttp://www.iana.org/assignments/enterprise-numbers.  Such      application-specific extensions should be maintained and published      by the application vendor.   Though RDSs and RRCs are designed to be stateless for an entire   reporting session, the framework requires an indication for the end   of the reporting.  For this purpose, an RDS MUST send a RAQMON NULL   PDU.  A NULL PDU is a RAQMON PDU containing ALL NULL values (i.e.,   nothing to report).2.4.  RDS/RRC Network Transport Protocol Requirements   The RAQMON PDUs rely on the underlying protocol(s) to provide   transport functionalities and other attributes of a transport   protocol, e.g., transport reliability, re-transmission, error   correction, length indication, congestion safety,   fragmentation/defragmentation, etc.  The maximum length of the RAQMON   data packet is limited only by the underlying protocols.   The following requirements MUST be met by the transport protocols:      1. The transport protocol SHOULD allow for RDS lightweight         implementations.  RDSs will be implemented on low-powered         embedded devices with limited device resources.      2. Scalability - Since RRCs need to interact with a very large         number (many tens, many hundreds, or more) of RDSs, scalability         of the transport protocol is REQUIRED.      3. Congestion safety - as per [RFC2914].  See alsoSection 3.Siddiqui, et al.            Standards Track                    [Page 10]

RFC 4710                    RAQMON Framework                October 2006      4. Security - Since RAQMON statistics may carry sensitive system         information requiring protection from unauthorized disclosure         and modification in transit, a transport protocol that provides         strong secure modes or allows for data encryption and integrity         to be applied is REQUIRED.      5. NAT-Friendly - The transport protocol SHOULD comply with         [RFC3235], so that an RDS could communicate with an RRC through         a Firewall/Network Address Translation device.      6. The transport protocol MAY implement session timeout mechanisms         to assume end of reporting for RDSs that have been out of         reporting for a reasonable duration of time.  Such timeout         parameters SHOULD be configurable in vendor implementations,         programmable at deployment.      7. Reliability - The RAQMON Framework expects PDUs to operate in         lossy networks.  However, retransmission is not included in the         RAQMON framework, in order to keep the design simple.  If         retransmission is a necessity, RAQMON MAY operate over         transport protocols, such as TCP.   In the future, if RAQMON PDUs are to be carried in an underlying   protocol that provides the abstraction of a continuous octet stream   rather than messages (packets), an encapsulation for the RAQMON   packets must be defined to provide a framing mechanism.  Framing is   also needed if the underlying protocol contains padding so that the   extent of the RAQMON payload cannot be determined.  No framing   mechanism is defined in this document.  Carrying several RAQMON   packets in one network or transport packet reduces header overhead.   Further memos like [RFC4712] describe how the PDU is transported over   existing protocols like the Transmission Control Protocol (TCP) or   the Simple Network Management Protocol (SNMP).3.  RAQMON Operation in Congestion-Safe Mode   RAQMON PDUs can be transmitted over multiple transport protocols.   The RAQMON Framework will be congestion safe, if a RAQMON PDU is   transported over TCP.   One solution to the congestion awareness problem could have been to   discourage the use of UDP entirely for RAQMON.  Though RAQMON PDUs   can be transported over TCP, some transports like SNMP over TCP are   not commonly practiced in practical deployments.Siddiqui, et al.            Standards Track                    [Page 11]

RFC 4710                    RAQMON Framework                October 2006   The use of UDP inherently increases the risks of network congestion   problems, as UDP itself does not define congestion prevention,   avoidance, detection, or correction mechanisms.  The fundamental   problem with UDP is that it provides no feedback mechanism to allow a   sender to pace its transmissions against the real performance of the   network.  While this tends to have no significant effect on extremely   low-volume sender-receiver pairs, the impact of high-volume   relationships on the network can be severe.  This problem could be   further aggravated by large RAQMON PDUs fragmented at the UDP level.   Transport protocols such as DCCP can also be used as underlying   RAQMON PDU transport, which provides flexibility of UDP style   datagram transmission with congestion control.   It should be noted that the congestion problem is not just between   RDS and RRC pairs, but whenever there is a high fan-in ratio,   congestion could occur (e.g., many RDSs reporting to an RRC).  Within   the RAQMON Framework using UDP as a transport, congestion safety can   be achieved in following ways:      1. Constant Transmission Rate: In a well-managed network, a         constant transmission rate policy (e.g., 1 RAQMON PDU per         device every N seconds) will ensure congestion safety as         devices are introduced into the network in a controlled manner.         For example, in an enterprise network, IP Phones are added in a         controlled manner, and a constant transmission rate policy can         be sufficient to ensure congestion-safe operation.  The         configured rate needs to be related to the expected peak number         of devices.  As a worst-case scenario, if the RDSs enforce an         administrative policy where the maximum PDU transmission rate         is no more than one RAQMON PDU every two minutes, a UDP-based         implementation can be as congestion safe as a TCP-based         implementation.  Such policies can be enforced while         configuring RDSs, and the timers for the constant rate need to         be randomly jittered.      2. Single outstanding requests: This approach requires that a         request be sent at the application level, then there is a wait         for some sort of response indicating that the request was         received before sending anything else.  This produces an effect         described by some as "ping-ponging":  traffic bounces back and         forth between two nodes like a ping-pong ball in a match.         Since there's only one ball in play between any two players at         any given time, most of the potential for congestion cascades         is eliminated.  For reliability and efficiency reasons, this         technique must include backed-off retransmissions.  For         example, if RAQMON PDUs are transported using SNMP INFORM PDUs         over UDP, a SNMP response from the RRC SHOULD be processed by         the RDS to implement this mechanism.  [RFC4712] specifies thatSiddiqui, et al.            Standards Track                    [Page 12]

RFC 4710                    RAQMON Framework                October 2006         if the SNMP notifications transport mapping mechanism is         implemented, it is RECOMMENDED to use INFORM PDUs, and it is         NOT RECOMMENDED to use Trap PDUs.         This pacing or serialization approach has the side-effect of         significantly reducing the maximum throughput, as transmission         occurs in only one direction at a time and there is at least a         2xRTT (round-trip time) delay between transmissions.  More         sophisticated algorithms (such as those in TCP and Stream         Control Transmission Protocol (SCTP)) have been developed to         address this, and it would be inappropriate to duplicate that         work at the application level.  Consequently, if greater         efficiency is required than that provided by this simple         approach, implementers SHOULD use TCP, SCTP, or another such         protocol.  But if one absolutely must use UDP, this approach         works.  It has been also used in other application scenarios         like SIP over UDP.      3. By restricting transmission to a maximum transmission unit         (MTU) size:  An RDS may be faced with a request to deliver a         large message using UDP as a transport.  Fragmentation of such         messages is problematic in several ways.  Loss of any fragment         requires time-out and retransmission of the message.  The         fragments are commonly transmitted out of the interface at         local interface (usually LAN) rates, without awareness of the         intervening network conditions.  For these reasons, it is         generally considered a bad practice to send large PDUs over         UDP.  If the MTU size is known, as an implementation, an RDS         should not allow an application to send more information by         limiting the size of transmissions over UDP to reduce the         effects of fragmentation.  As an alternate, an RDS MAY also         send parameters to RRC over multiple RAQMON PDUs but identify         them as part of the same RAQMON reporting session with exactly         the same Network Time Protocol (NTP) [RFC1305] time stamp.         While the actual MTU of a link may not be known, common         practice seems to indicate that the RDS local interface MTU is         likely to be a reasonable "approximation".  Where the actual         path MTU is known, that value SHOULD be used instead.      4. Irrespective of choice of transport protocol, it is also         RECOMMENDED that no more than 10% network bandwidth be used for         RDS/RRC reporting.  More frequent reports from an RDS to RRC         would imply requirements for higher network bandwidth usage.Siddiqui, et al.            Standards Track                    [Page 13]

RFC 4710                    RAQMON Framework                October 20064.  Measurement Methodology   It is not the intent of this document to recommend a methodology to   measure any of the QoS parameters defined inSection 5.  Measurement   algorithms are left to the implementers and equipment vendors to   choose.  There are many different measurement methodologies available   for measuring application performance.  These include probe-based,   client-based, synthetic-transaction, and other approaches.  This   specification does not mandate a particular methodology and is open   to any methodology that meets the minimum requirements.  For   conformance to this specification, it is REQUIRED that the collected   data match the semantics described herein.  However, it is   RECOMMENDED that vendors use IETF-defined and International   Telecommunication Union (ITU)-specified methodologies to measure   parameters when possible.5.  Metrics Pre-Defined for the BASIC Part of the RAQMON PDU   The BASIC part of the RAQMON PDU provides for a list of pre-defined   parameters frequently used by applications to characterize end-to-end   application Quality of Service.  This section defines a set of simple   metrics to be contained in the BASIC part of the RAQMON PDU, through   reference to existing IETF, ITU, and other standards organizations'   documents.  Appropriate IETF or ITU references are included in the   metrics definitions.   As mentioned earlier, the RAQMON PDU also contains an application-   specific part, where application- and vendor-specific information not   included in BASIC part can be added as <Name, Value> pairs, or as a   variable binding list.  These extensions, managed independently by   vendors or other organizations, should be published for wider   interoperability.   Applications are not required to report all the parameters mentioned   in this section, but should have the flexibility to report a subset   of these parameters appropriate to an application context.  The memo   further identifies the parameters that RDSs are required to include   in all PDUs for compliance, as well as optional parameters that RDSs   may report as needed.  The definitions presented here are meant to   provide guidance to implementers, and IETF metric definition   references are provided for each metric.  Application developers   should choose the metrics appropriate to their applications' needs.   Syntactical representations of the parameters identified here are   provided in the [RFC4712] specification.Siddiqui, et al.            Standards Track                    [Page 14]

RFC 4710                    RAQMON Framework                October 20065.1.  Data Source Address (DA)   The Data Source Address (DA) is the address of the data source.  This   could be either a globally unique IPv4 or IPv6 address, or a   privately IPv4 allocated address as defined in [RFC1918].   It is expected that the DA would remain constant within a given   communication session.  RDSs SHOULD avoid sending these parameters   within RAQMON reports too often to ensure an efficient usage of   network resources.5.2.  Receiver Address (RA)   The Receiver Address (RA) takes the same form as the Data Source   Address (DA) but represents the Receiver's Address.  In a   communication session, the reporting RDSs SHOULD fill in the other   party's address as a Receiver Address.  Like the Data Source Address,   this could be either a globally unique IPv4 or IPv6 address, or a   privately allocated IPv4 address as defined in [RFC1918].   It is expected that the Receiver Address (RA) would remain constant   within a given communication session.  RDSs SHOULD avoid sending   these parameters within RAQMON reports too often in order to ensure   an efficient usage of network resources.5.3.  Data Source Name (DN)   The Data Source Name (DN) item could be of various formats as needed   by the application.  Forms the DN could take include, but are not   restricted to:      - "user@host", or "host" if a user name is not available as on        single-user systems.  For both of these formats, "host" is the        fully qualified domain name of the host from which the payload        originates, formatted according to the rules specified in        [RFC1034], [RFC1035], andSection 2.1 of [RFC1123].  Use example        names are "big-guy@example.com" or "big-guy@192.0.2.178" for a        multi-user system.  On a system with no user name, an example        would be "ip-phone4630.example.com".  It is RECOMMENDED that the        standard host's numeric address not be reported via the DN        parameter, as the DA parameter is used for that purpose.      - Another instance of a DN could be a valid E.164 phone number, a        SIP URI, or any other form of telephone or pager number.  The        phone number SHOULD be formatted with a plus sign replacing the        international access code.  Example: "+44-116-496-0348" for a        number in the UK.Siddiqui, et al.            Standards Track                    [Page 15]

RFC 4710                    RAQMON Framework                October 2006   The DN value is expected to remain constant for the duration of a   session.  RDSs SHOULD avoid sending these parameters within RAQMON   reports too often in order to ensure an efficient usage of network   resources.5.4.  Receiver Name (RN)   The Receiver Name (RN) takes the same form as DN, but represents the   Receiver's name.  In a communication session, an application SHOULD   supply as an RN the name of the other party with which it is   communicating.   The RN value is expected to remain constant for the duration of a   session.  RDSs SHOULD avoid sending these parameters within RAQMON   reports too often in order to ensure an efficient usage of network   resources.5.5.  Data Source Device Port Used   This parameter indicates the source port used by the application for   a particular session or sub-session in communication.  Examples of   ports include TCP Ports or UDP Ports, as used by communication   application protocols such as Session Initiation Protocol (SIP), SIP   for Instant Messaging and Presence Leveraging Extensions (SIMPLE),   H.323, RTP, HyperText Transport Protocol (HTTP), and so on.   This parameter MUST be sent in the first RAQMON PDU.5.6.  Receiver Device Port Used   This parameter indicates the receiver port used by the application   for a particular session or sub-session.  Examples of ports include   TCP Ports, or UDP Ports used by communication application protocols   such as SIP, SIMPLE, H.323, RTP, HTTP, etc.   This parameter MUST be sent in the first RAQMON PDU.5.7.  Session Setup Date/Time   This parameter gives the time when the setup was initiated, if the   application has a setup phase, or when the session was started, if   such a setup phase does not exist.  The time is represented using the   timestamp format of the Network Time Protocol (NTP), which is in   seconds relative to 0h UTC (Coordinated Universal Time) on 1 January   1900 [RFC1305].   This parameter SHOULD be sent only in the first RAQMON PDU, after the   session setup is completed.Siddiqui, et al.            Standards Track                    [Page 16]

RFC 4710                    RAQMON Framework                October 20065.8.  Session Setup Delay   The Session Setup Delay metric reports the time taken from an   origination request being initiated by a host/endpoint to the media   path being established (or a session progress indication being   received from the remote host/endpoint), expressed in milliseconds.   For example, in VoIP systems, a session setup time can be measured as   the interval from the last DTMF (dual-tone multi-frequency) button   pushed to the first ring-back tone that indicates that the far end is   ringing.  Another example would be the Session Setup Delay of a SIP   call, which is measured as the elapsed time between when an INVITE is   generated by a User Agent and when the 200 OK is received.   This parameter SHOULD be sent only in the first RAQMON PDU, after the   session setup is completed.5.9.  Session Duration   The Session Duration metric reports how long a session or a sub-   session lasted.  This metric is application context sensitive.  For   example, a VoIP Call Session Duration can be measured as the elapsed   time between call pickup and call termination, including session   setup time.   This parameter SHOULD be sent only in the first RAQMON PDU, after the   session is terminated.5.10.  Session Setup Status   The Session Setup Status metric is intended to report the   communication status of a session.  Its values identify appropriate   communication session states, such as Call Progressing, Call   Established successfully, "trying", "ringing", "re-trying", "RSVP   reservation failed", and so on.   Session setup status is meaningful in the context of applications.   For this reason, applications SHOULD use this metric together with   the application/name metrics defined inSection 5.32.   This information could be used by network management systems to   calculate parameters such as call success rate, call failure rate,   etc., or by a debugging tool that captures the status of a call's   setup phase as soon as a call is established.   This parameter SHOULD be sent after each change in the session   status.Siddiqui, et al.            Standards Track                    [Page 17]

RFC 4710                    RAQMON Framework                October 20065.11.  Round-Trip End-to-End Network Delay   The Round-Trip End-to-End Network Delay, defined in [RFC3550] for   applications running over RTP and in [RFC2681] for all other IP   applications, is a key metric for Application QoS Monitoring.  Some   applications do not perform well (or at all) if the end-to-end delay   between hosts is large relative to some threshold value.  Erratic   variation in delay values makes it difficult (or impossible) to   support many real-time applications such as Voice over IP, Video over   IP, Fax over IP etc.   The Round-Trip End-to-End Network delay of the underlying transport   network is measured using methodologies described in [RFC3550] for   RTP and in [RFC2681] for other IP applications.   Note that the packets used for measurement in some methodologies may   be of a different type from those used for media (e.g., ICMP instead   of RTP) and hence may differ in terms of route and queue priority.   This may result in measured delays being different from those   experienced on the media path.  Conformance for this metric requires   that actual application packets, or packets of the same application   type, be used.   Support for RTP can be determined by the support of the RTP MIB   [RFC2959] in the hosts running the applications or by inclusion of   the string 'RTP' at the beginning of the Application Name (Section5.32).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.12.  One-Way End-to-End Network Delay   The One-Way End-to-End Network Delay [RFC2679] metric reports the   One-Way End-to-End delay encountered by traffic from the source to   the destination network interface.  One-Way Delay measurements   identified by the IP Performance Metrics (IPPM) Working Group   [RFC2679] will be used to measure one-way end-to-end network delay.   The need for such a metric is derived from the fact that the path   from a source to a destination may be different from the path from   the destination back to the source ("asymmetric paths"), such that   different sequences of routers are used for the forward and reverse   paths.  Therefore, round-trip measurements actually measure the   performance of two distinct paths together.Siddiqui, et al.            Standards Track                    [Page 18]

RFC 4710                    RAQMON Framework                October 2006   Measuring each path independently highlights the performance   difference between the two paths that may traverse different Internet   service providers, and even radically different types of networks   (for example, research versus commodity networks, or ATM   (Asynchronous Transfer Mode) versus Packet-over-SONET (Synchronous   Optical) transport networks).   Even when the two paths are symmetric, they may have radically   different performance characteristics due to asymmetric queuing.   Performance of an application may depend mostly on the performance in   one direction.  For example, a file transfer using TCP may depend   more on the performance in the direction that data flows than on the   direction in which acknowledgements travel.   In QoS-enabled networks, provisioning in one direction may be   radically different from provisioning in the reverse direction, and   thus the QoS guarantees differ.  Measuring the paths independently   allows the verification of both guarantees.   RAQMON SHOULD NOT derive One-Way End-to-End Network Delay by assuming   Internet paths are symmetric (i.e., dividing Round-Trip Delay by   two).   Note that the packets used for measurement in some methodologies may   be of a different type from those used for media (e.g., ICMP instead   of RTP) and hence may differ in terms of route and queue priority.   This may result in measured delays being different from those   experienced on the media path.  Conformance for this metric requires   that actual application packets, or packets of the same application   type, be used.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.13.  Application Delay   Various Network Delay versions, as outlined in Sections5.11 and   5.12, do not include delays associated with buffering, play-out,   packet-sequencing, coding/decoding, etc., in the end-devices.  The   Application Delay metric defined in this section is targeted to   capture all such delay parameters, providing a total application   endpoint delay.   Application delay can be expressed as the time delay introduced   between the network interface and the application-level presentation.   Since it is difficult to envision usage of all sorts of applications,Siddiqui, et al.            Standards Track                    [Page 19]

RFC 4710                    RAQMON Framework                October 2006   the following guidance is provided to the implementers to measure the   application delay:   - The sending end contribution to application delay is defined as the     sum of sample sequencing, accumulation, and encoding delay.   - The receiving end contribution to application delay is calculated     as the sum of delays associated with buffering, play-out, packet-     sequencing, and decoding associated with the receiving direction,     if relevant.   The endpoint application delay is defined as the sum of the receiving   and sending contributions to delay measured or estimated within the   endpoint that is generating this report.   It is easy to recognize that applications running on an IP device can   experience same network delay but have different application-   associated delay values.  As such, the user experience associated   with specific applications may vary while the network delay value   remains same for both the applications.   Having network delay and application delay measurements available, a   management application can represent the delay experienced by the end   user at the application level as a sum of network delay and the   application delays reported from the endpoints.  However, the   specification of such a management application is outside the scope   of the RAQMON specification.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.14.  Inter-Arrival Jitter   The Inter-Arrival Jitter metric provides a short-term measure of   network congestion [RFC3550].  The jitter measure may indicate   congestion before it leads to packet loss.  The inter-arrival jitter   field is only a snapshot of the jitter at the time when a RAQMON PDU   is generated and is not intended to be taken quantitatively as   indicated in [RFC3550].  Rather, it is intended for comparison of   inter-arrival jitter from one receiver over time.  Such inter-arrival   jitter information is extremely useful to understand the behavior of   certain applications such as Voice over IP, Video over IP, etc.   Inter-arrival jitter information is also used in the sizing of play-   out buffers for applications requiring the regular delivery of   packets (for example, voice or video play-out).Siddiqui, et al.            Standards Track                    [Page 20]

RFC 4710                    RAQMON Framework                October 2006   In [RFC3550], the selection function is implicitly applied to   consecutive packet pairs, and the "jitter estimate" is computed by   applying an exponential filter with parameter 1/16 to generate the   estimate (i.e., j_new = 15/16* j_old + 1/16*j_new).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.15.  IP Packet Delay Variation   [RFC3393] provides guidance to several absolute jitter parameters.   RAQMON uses the [RFC3393] definition of the IP Packet Delay Variation   (ipdv) for packets inside a stream of packets.  The IP Delay   Variation metric is used to determine the dynamics of queues within a   network (or router) where the changes in delay variation can be   linked to changes in the queue length processes at a given link or a   combination of links.  Such a parameter provides visibility within an   IP Network and a better understanding of application-level   performance problems as it relates to IP Network performance.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.16.  Total Number of Application Packets Received   This metric reports the number of application payload packets   received by the RDS as part of this session since the last RAQMON PDU   was sent up until the time this RAQMON PDU was generated.   This parameter represents a very simple incremental counter that   counts the number of "application" packets that an RDS has received.   Application packets MAY include signaling packets.  Since this count   is a snapshot in time, depending on application type, it also varies   based on the application states, e.g., an RDS within an application   session will report the aggregated number of application packets that   were sent out during signaling setup, media packets received, session   termination, etc.   For example, during Voice over IP or Video over IP sessions setup,   this counter represents the number of signaling-session-related   packets that have been received that will be derived from the   relevant application signaling protocol stack such as SIP or H.323,   SIMPLE, and various other signaling protocols used by the application   to establish the communication session.Siddiqui, et al.            Standards Track                    [Page 21]

RFC 4710                    RAQMON Framework                October 2006   However, during a period when media is established between the   communicating entities, this counter will be indicative of the number   of RTP Frames that have been sent out to the communicating party   since last PDU was sent out.  The methodology described within RTCP   SR/RR reports [RFC3550] to count RTP frames will be applied wherever   applications use RTP.  This being a cumulative counter, applications   need to take into consideration the possibility of the counter   overflowing and restarting counting from zero.   Support for RTP can be determined by the support of the RTP MIB   [RFC2959] in the hosts running the applications or by inclusion of   the string 'RTP' at the beginning of the Application Name (Section5.32).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.17.  Total Number of Application Packets Sent   This metric reports the number of signaling and payload packets sent   by the RDS as part of this session since the last RAQMON PDU was sent   until the time this RAQMON PDU was generated.  Applications packets   MAY include signaling packets.  Similar to the total number of   application packets received parameter inSection 5.16, this count is   a snapshot in time.  Depending on the application type, the counter   also varies based on various application states, including packet   counts for signaling setup, media establishment, session termination   states, and so on.  This being a cumulative counter, applications   need to take into consideration the possibility of the counter   overflowing and restarting counting from zero.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.18.  Total Number of Application Octets Received   This metric reports the total number of signaling and payload octets   received in packets by the RDS as part of this session since the last   RAQMON PDU was sent, up until the time this RAQMON packet was   generated.  Applications octets MAY include signaling octets.  The   methodology described by [RFC3550] will be applied wherever   applications use RTP.  This being a cumulative counter, applications   need to take into consideration the possibility of the counter   overflowing and restarting counting from zero.Siddiqui, et al.            Standards Track                    [Page 22]

RFC 4710                    RAQMON Framework                October 2006   Support for RTP can be determined by the support of the RTP MIB   [RFC2959] in the hosts running the applications or by inclusion of   the string 'RTP' at the beginning of the Application Name (Section5.32).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.19.  Total Number of Application Octets Sent   This metric reports the total number of signaling and payload octets   received in packets by the RDS as part of this session since the last   RAQMON PDU was sent, up until the time this RAQMON packet was   generated.  This is similar to the Total Number of Application Octets   Received metric.  Applications octets MAY include signaling octets.   The methodology described by [RFC3550] will be applied wherever   applications use RTP.  This being a cumulative counter, applications   need to take into consideration the possibility of the counter   overflowing and restarting counting from zero.   Support for RTP can be determined by the support of the RTP MIB   [RFC2959] in the hosts running the applications or by inclusion of   the string 'RTP' at the beginning of the Application Name (Section5.32).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.20.  Cumulative Packet Loss   The cumulative packet loss metric indicates the loss associated with   the network as well as local device losses over time.  This parameter   is counted as the total number of application packets from the source   that have been lost since the beginning of the session.  This number   is defined to be the number of packets expected less the number of   packets actually received, where the number of packets received   includes the count of packets that are late or duplicates.  If a   packet is discarded due to late arrival, then it MUST be counted as   either lost or discarded but MUST NOT be counted as both.   Packet loss by the underlying transport network SHALL be measured   using the methodologies described in [RFC3550] for RTP traffic and   [RFC2680] for other IP traffic.  The number of packets expected is   defined to be the extended last sequence number received, as definedSiddiqui, et al.            Standards Track                    [Page 23]

RFC 4710                    RAQMON Framework                October 2006   next, less the initial sequence number received.  For RTP traffic,   this may be calculated using techniques such as those shown inAppendix A.3 of [RFC3550].   Packet loss by the underlying transport network SHALL be measured   using the methodologies described in [RFC3550] for RTP traffic and   [RFC2680] for other IP traffic.  The number of packets expected is   defined to be the extended last sequence number received, as defined   next, less the initial sequence number received.  For RTP traffic,   this may be calculated using techniques such as those shown inAppendix A.3 of [RFC3550].   Support for RTP can be determined by the support of the RTP MIB   [RFC2959] in the hosts running the applications or by inclusion of   the string 'RTP' at the beginning of the Application Name (Section5.32).   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.21.  Packet Loss in Fraction   The Packet Loss in Fraction metric represents the packet loss as   defined above, but expressed as a fraction of the total traffic over   time.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.22.  Cumulative Application Packet Discards   The RAQMON Framework allows applications to distinguish between   packets lost by the network and those discarded due to jitter and   other application-level errors.  Though packet loss and discards have   an equal effect on the quality of the application, having separate   counts for packet loss and discards helps identify the source of   quality degradation.   The packet discard metric indicates packets discarded locally by the   device over time.  Local device-level packet discard is captured as   the total number of application-level packets from the source that   have been discarded since the beginning of reception, due to late or   early arrival, under-run or overflow at the receiving jitter buffer,   or any other application-specific reasons.Siddiqui, et al.            Standards Track                    [Page 24]

RFC 4710                    RAQMON Framework                October 2006   If the RDS cannot tell the difference between discards and lost   packets, then it MUST report only lost packets and MUST NOT report   discards.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.23.  Packet Discards in Fraction   The packet discards in fraction metric represents packets from the   source that have been discarded since the beginning of the reception   but expressed as a fraction of the total traffic over time.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.24.  Source Payload Type   The source payload type reports payload formats (e.g., media   encoding) as sent by the data source, e.g., ITU G.711, ITU G.729B,   H.263, MPEG-2, ASCII, etc.  This memo follows the definition of   Payload Type (PT) in [RFC3551].  For example, to indicate that the   source payload type used for a session is PCMA (pulse-code modulation   with A-law scaling), the value of the source payload field for the   respective session will be 8.   The source payload type value is expected to remain constant for the   duration of a session, with the exception of events like dynamic   codec changes.  RDSs SHOULD avoid sending these parameters within   RAQMON reports more often than necessary (e.g., at dynamic codec   changes) to ensure an efficient usage of network resources.   If dynamic types (values 96 to 127, according to [RFC3551]) are being   used to identify the source payload type, a RAQMON extension   parameter MAY be defined to indicate the MIME subtypes.  In the case   where the RDS does send reports noting dynamic codec changes, there   may be instances where this extension parameter is used only before   or after the codec change, as the source payload may shift between   the dynamic and static types.5.25.  Receiver Payload Type   The receiver payload type reports payload formats (e.g., media   encodings) as sent by the other communicating party back to the   source, e.g., ITU G.711, ITU G.729B, H.263, MPEG-2, ASCII, etc.  This   document follows the definition of payload type (PT) in [RFC3551].Siddiqui, et al.            Standards Track                    [Page 25]

RFC 4710                    RAQMON Framework                October 2006   For example, to indicate that the destination payload type used for a   session is PCMA, the destination payload type field for the   respective session will be 8.   The destination payload type value is expected to remain constant for   the duration of a session, with the exception of events like dynamic   codec changes.  RDSs SHOULD avoid sending these parameters within   RAQMON reports more often than necessary (e.g., at dynamic codec   changes) to ensure an efficient usage of network resources.   If dynamic types (values 96 to 127, according to [RFC3551]) are being   used to identify the destination payload type, a RAQMON extension   parameter MAY be defined to indicate the MIME subtypes.  In the case   where the RDS does send reports noting dynamic codec changes, there   may be instances where this extension parameter is used only before   or after the codec change, as the destination payload may shift   between the dynamic and static types.5.26.  Source Layer 2 Priority   Many devices use Layer 2 technologies to prioritize certain types of   traffic in the Local Area Network environment.  For example, the 1998   Edition of IEEE 802.1D [IEEE802.1D], "Media Access Control Bridges",   contains expedited traffic capabilities to support transmission of   time-critical information.  Many devices use that standard to mark   Ethernet frames according to IEEE P802.1p standard.  Details on these   can be found in [IEEE802.1D], which incorporates P802.1p.  The Source   Layer 2 Priority RAQMON field indicates what Layer 2 values were used   by the host running the RDS to prioritize these packets in the Local   Area Network environment.   The Source Layer 2 Priority value is expected to remain constant for   the duration of a session.  Hosts running the RDSs SHOULD avoid   sending these parameters within RAQMON reports too often in order to   ensure an efficient usage of network resources.5.27.  Source TOS/DSCP Value   Various Layer 3 technologies are in place to prioritize traffic in   the Internet.  For example, the traditional IP Precedence [RFC791]   and Type of Service (TOS) [RFC1812], or more recent technologies like   Differentiated Services [RFC2474] [RFC2475], use the TOS octet in   IPv4, whereas the traffic class octet is used to prioritize traffic   in IPv6.  Source Layer TOS/DCP RAQMON field reports the appropriate   Layer 3 values used by the Data Source to prioritize these packets.Siddiqui, et al.            Standards Track                    [Page 26]

RFC 4710                    RAQMON Framework                October 2006   The Source TOS/DSCP value is expected to remain constant for the   duration of a session.  Hosts running the RDSs SHOULD avoid sending   these parameters within RAQMON reports too often in order to ensure   an efficient usage of network resources.5.28.  Destination Layer 2 Priority   The Destination Layer 2 Priority reports the Layer 2 value used by   the communication receiver to prioritize packets while sending   traffic to the data source in the Local Area Networks environment.   Like Source Layer 2 Priority, Destination Layer 2 Priority could   indicate whether the destination has used Layer 2 technologies like   IEEE P802.1p for priority queuing.   The Destination Layer 2 Priority value is expected to remain constant   for the duration of a session.  Hosts running the RDSs SHOULD avoid   sending these parameters within RAQMON reports too often in order to   ensure an efficient usage of network resources.5.29.  Destination TOS/DSCP Value   The Destination TOS/DSCP RAQMON field reports the values used by the   Data Receiver to prioritize these packets received by the source.   Similar to Source Layer 3 Priority, Destination Layer 3 Priority   indicates whether the destination has used any Layer 3 technologies   like IP Precedence [RFC791] and Type of Service (TOS) [RFC1812], or   more recent technologies like Differentiated Service [RFC2474]   [RFC2475].   The Destination TOS/DSCP value is expected to remain constant for the   duration of a session.  Hosts running the RDSs SHOULD avoid sending   these parameters within RAQMON reports too often in order to ensure   an efficient usage of network resources.5.30.  CPU Utilization in Fraction   This parameter captures the CPU usage of the hosts running the RDSs   that may have very critical implications for QoS of an end-device.   It is computed as an average since the last reporting interval, and   corresponds to the percentage of that time that the CPU was busy.   In the case of multiple CPU hosts, the maximum utilization among the   different CPUs MUST be reported.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.Siddiqui, et al.            Standards Track                    [Page 27]

RFC 4710                    RAQMON Framework                October 20065.31.  Memory Utilization in Fraction   This parameter captures the memory usage of the hosts running the   RDSs that may have very critical implications for QoS of an end-   device.  It is computed as an average since the last reporting   interval and corresponds to the average percentage of the total   memory space critical for the applications in use during that time   interval (e.g., primary CPU RAM, buffers).   In the case of multiple CPU hosts, the maximum memory utilization   among the different CPUs MUST be reported.   This parameter SHOULD be sent in each RAQMON PDU, if the RDS has the   capability of determining its value and if the parameter is relevant   for the application.5.32.  Application Name/Version   The Application Name/Version parameter gives the name and,   optionally, the version of the application associated with that   session or sub-session, e.g., "XYZ VoIP Agent 1.2".  This information   may be useful for scenarios where the end-device is running multiple   applications with various priorities and could be very handy for   debugging purposes.   If the application is using RTP [RFC3550], the Application Name   SHOULD begin with the string 'RTP'.   This parameter MUST be sent in the first RAQMON PDU.6.  Report Aggregation and Statistical Data processing   Within the RAQMON Framework, RRCs are expected to have significantly   greater computational resources than RDSs.  Consequently, various   aggregation functions are performed by the RRCs, while RDSs are not   burdened by statistical data processing such as computation of   minima, maxima, averages, standard deviations, etc.   The RAQMON MIB provides minimal aggregation of the RAQMON parameters   defined above.  The RAQMON MIB is not designed to provide extensive   aggregation like the Application Performance Measurement (APM) MIB   [RFC3729] or the Transport Performance Metrics (TPM) MIB [RFC4150].   One should use APM and TPM MIBs to aggregate parameters based on   protocols (e.g., performance of HTTP, RTP) or applications (e.g.,   performance of VoIP, Video Applications).Siddiqui, et al.            Standards Track                    [Page 28]

RFC 4710                    RAQMON Framework                October 2006   In the RAQMON MIB, aggregation can be performed only on specific   RAQMON metric parameters.  Aggregation always results in statistical   Mean/Min/Max values, according to these definitions:      Mean: Mean is defined as the statistical average of a metric over            the duration of a communication session.  For example, if an            RDS reported End-to-End delay metric N times within a            communication session, then the Mean End-to-End Delay can be            computed by summing of these N reported values, and then            dividing by N.      Min:  Min is defined as the statistical minimum of a metric over            the duration of a communication session.  For example, if            the end-to-end delay metric of an end-device within a            communication session is reported N times by the RDS, then            the Min end-to-end delay is the smallest of the N end-to-end            delay metric values reported.      Max:  Max is defined as the statistical maximum of a metric over            the duration of a communication session.  For example, if            the end-to-end delay metric of an end-device within a            communication session is reported N times by the RDS, then            the Max End-to-End Delay is the largest of the N End-to-End            Delay metric values reported.7.  Keeping Historical Data and Storage   It is evident from the document that the RAQMON MIB data need to be   managed to optimize storage space.  The large volume of data gathered   in a communication session could be optimized for storage space by   performing and storing only aggregated RAQMON metrics for history if   required.   Examples of how such storage space optimization can be performed   include:      1. Make data available through the MIB only at the end of a         communication session, i.e., upon receipt of a NULL PDU.  The         aggregated data could be made available using the RAQMON MIB as         Mean, Max, or Min entries and saved for historical purposes.      2. Use a time-based algorithm that aggregates data over a specific         period of time within a communication session, thus requiring         fewer entries, to reduce storage space requirements.  For         example, if an RDS sends data out every 10 seconds and the RRC         updates the RAQMON MIB once every minute, for every 6 data         points there would be one MIB entry.Siddiqui, et al.            Standards Track                    [Page 29]

RFC 4710                    RAQMON Framework                October 2006      3. Periodically delete historical data in accordance with an         administrative policy.  An example of such a policy would be to         delete historical data older than 60 days.  The implementation         of such policies is left to the application developer's         discretion, and their use is an operational concern.8.  Security Considerations   Security considerations associated with the RAQMON Framework are   discussed below, and in greater detail in other RAQMON memos as is   appropriate.8.1.  The RAQMON Threat Model   The vulnerabilities associated with the RAQMON Framework are a   combination of those associated with the underlying layers up to the   transport layer, and of possible exploits of RAQMON payload.   Possible exploits of RAQMON payloads fall within these classes:      1. Unauthorized examination of sensitive information in the         payload in transit.      2. Unauthorized modification of payload contents in transit,         leading to:         a. Mis-identification of information from one RAQMON reporting            session as belonging to another destined to the same RRC;         b. Mismapping of RAQMON sessions;         c. Various forms of session-level denial-of-service (DoS)            attacks;         d. DoS through modification of RAQMON parameter values and            statistics;         e. Invalid timestamps, leading to false interpretation of the            monitored data, affecting call records information, and            making difficult to place monitoring events in their            appropriate temporal context.      3. Malformed payloads, permitting the exploitation of potential         implementation weaknesses to compromise an RRC.      4. Unauthorized disclosure of sensitive data carried by         application PDUs, leading to a breach of confidentiality.Siddiqui, et al.            Standards Track                    [Page 30]

RFC 4710                    RAQMON Framework                October 2006   Consequently, threats based on  unauthorized disclosure or   modification of payloads or headers will have to be assumed.8.2.  The RAQMON Security Requirements and Assumptions   In order to preserve integrity of the RAQMON PDU against these   threats, the RAQMON model must provide for cryptographically strong   security services.   Consequently, the RAQMON framework must be able to provide for the   following protections:      1. Authentication - the RRC should be able to verify that a RAQMON         PDU was in fact originated by the RDS that claims to have sent         it.      2. Privacy - Since RAQMON information includes identification of         the parties participating in a communication session, the         RAQMON framework should be able to provide for protection from         eavesdropping, to prevent an unauthorized third party from         gathering potentially sensitive information.  This can be         achieved by using various payload encryption technologies, such         as Data Encryption Standard (DES), 3-DES, Advanced Encryption         Standard (AES), etc.      3. Protection from DoS attacks directed at the RRC - RDSs send         RAQMON reports as a side effect of an external event (for         example, a phone call is being received).  An attacker can try         to overwhelm the RRC (or the network) by initiating a large         number of events (i.e., calls) for the purpose of swamping the         RRC with too many RAQMON PDUs.         To prevent DoS attacks against RRC, the RDS will send the first         report for a session only after the session has been in         progress for the five-second reporting interval.  Sessions         shorter than that should be stored in the RDS and will be         reported only after that interval has expired.8.3.  RAQMON Security Model   The RAQMON architecture permits the use of multiple transport   protocols.  Most of these support a secure mode of operation.  There   are advantages to relying on the security provided at the transport   protocol layer.      1. Transport-protocol-level security can generally protect the         payload with end-to-end authentication, confidentiality,         message integrity, and replay protection services.Siddiqui, et al.            Standards Track                    [Page 31]

RFC 4710                    RAQMON Framework                October 2006      2. A good cryptographic security protocol always has an associated         key management protocol.  Use of transport protocol security         relies on its key management and does not require development         of another mechanism.      3. When transport protocol security is already enabled between the         RDS and RRC, additional encryption and message authentication         at the application level is avoided.   However, there are also shortcomings to be noted in relying on   transport protocol security.      1. When session-level isolation of the different RAQMON sessions         of an RDS-RRC pair is required, it will be necessary to open         separate transport protocol instances.  Such cases, however,         may be rare.      2. Since security services are not provided by the RAQMON         framework, the absence of transport or lower protocol security         implies the absence of RAQMON security.9.  Acknowledgements   The authors would like to thank Andy Bierman, Alan Clark, Mahalingam   Mani, Colin Perkins, Steve Waldbusser, Magnus Westerlund, and Itai   Zilbershtein for the precious advices and real contributions brought   to this document.  The authors would also like to extend special   thanks to Randy Presuhn, who reviewed this document for spelling and   formatting purposes, and who provided a deep review of the technical   content.  We also would like to thank Bert Wijnen for the permanent   coaching during the evolution of this document and the detailed   review of its final versions.Siddiqui, et al.            Standards Track                    [Page 32]

RFC 4710                    RAQMON Framework                October 200610.  Normative References   [RFC791]     Postel, J., "Internet Protocol", STD 5,RFC 791,                September 1981.   [RFC1812]    Baker, F., "Requirements for IP Version 4 Routers",RFC1812, June 1995.   [RFC2119]    Bradner, S., "Key words for use in RFCs to Indicate                Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC2474]    Nichols, K., Blake, S., Baker, F., and D. Black,                "Definition of the Differentiated Services Field (DS                Field) in the IPv4 and IPv6 Headers",RFC 2474, December                1998.   [RFC2475]    Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,                and W. Weiss, "An Architecture for Differentiated                Service",RFC 2475, December 1998.   [RFC2679]    Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way                Delay Metric for IPPM",RFC 2679, September 1999.   [RFC2680]    Almes, G., Kalidindi, S., and M. Zekauskas, "A One-way                Packet Loss Metric for IPPM",RFC 2680, September 1999.   [RFC2681]    Almes, G., Kalidindi, S., and M. Zekauskas, "A Round-                trip Delay Metric for IPPM",RFC 2681, September 1999.   [RFC2819]    Waldbusser, S., "Remote Network Monitoring Management                Information Base", STD 59,RFC 2819, May 2000.   [RFC2959]    Baugher, M., Strahm, B., and I. Suconick, "Real-Time                Transport Protocol Management Information Base",RFC2959, October 2000.   [RFC3393]    Demichelis, C. and P. Chimento, "IP Packet Delay                Variation Metric for IP Performance Metrics (IPPM)",RFC3393, November 2002.   [RFC3416]    Presuhn, R., Ed., "Version 2 of the Protocol Operations                for the Simple Network Management Protocol (SNMP)", STD                62,RFC 3416, December 2002.   [RFC3550]    Schulzrinne, H., Casner, S., Frederick, R., and V.                Jacobson, "RTP: A Transport Protocol for Real-Time                Applications", STD 64,RFC 3550, July 2003.Siddiqui, et al.            Standards Track                    [Page 33]

RFC 4710                    RAQMON Framework                October 2006   [RFC3551]    Schulzrinne, H. and S. Casner, "RTP Profile for Audio                and Video Conferences with Minimal Control", STD 65,RFC3551, July 2003.11.  Informative References   [RFC1034]    Mockapetris, P., "Domain names - concepts and                facilities", STD 13,RFC 1034, November 1987.   [RFC1035]    Mockapetris, P., "Domain names - implementation and                specification", STD 13,RFC 1035, November 1987.   [RFC1123]    Braden, R., "Requirements for Internet Hosts -                Application and Support", STD 3,RFC 1123, October 1989.   [RFC1305]    Mills, D., "Network Time Protocol (Version 3)                Specification, Implementation and Analysis",RFC 1305,                March 1992.   [RFC1918]    Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot,                G., and E. Lear, "Address Allocation for Private                Internets",BCP 5,RFC 1918, February 1996.   [RFC2914]    Floyd, S., "Congestion Control Principles",BCP 41,RFC2914, September 2000.   [RFC3235]    Senie, D., "Network Address Translator (NAT)-Friendly                Application Design Guidelines",RFC 3235, January 2002.   [RFC3611]    Friedman, T., Caceres, R., and A. Clark, "RTP Control                Protocol Extended Reports (RTCP XR)",RFC 3611, November                2003.   [RFC3729]    Waldbusser, S., "Application Performance Measurement                MIB",RFC 3729, March 2004.   [RFC4150]    Dietz, R. and R. Cole, "Transport Performance Metrics                MIB",RFC 4150, August 2005.   [RFC4711]    Siddiqui, A., Romascanu, D., and E. Golovinsky, "Real-                time Application Quality-of-Service Monitoring (RAQMON)                MIB",RFC 4711, October 2006.   [RFC4712]    Siddiqui, A., Romascanu, D., Golovinsky, E., Ramhman,                M., and Y. Kim, "Transport Mappings for Real-time                Application Quality-of-Service Monitoring (RAQMON)                Protocol Data Unit (PDU)",RFC 4712, October 2006.Siddiqui, et al.            Standards Track                    [Page 34]

RFC 4710                    RAQMON Framework                October 2006   [IEEE802.1D] Information technology - Telecommunications and                information exchange between systems - Local and                metropolitan area networks - Common Specification a -                Media access control (MAC) bridges:15802-3:  1998                (ISO/IEC). Revision. This is a revision of ISO/IEC                10038: 1993, 802.1j-1992 and 802.6k-1992.  It                incorporates P802.11c, P802.1p and P802.12e [ANSI/IEEE                Std 802.1D, 1998 Edition]Authors' Addresses   Anwar A. Siddiqui   Avaya Labs   307 Middletown Lincroft Road   Lincroft, New Jersey 07738   USA   Phone: +1 732 852-3200   EMail: anwars@avaya.com   Dan Romascanu   Avaya   Atidim Technology Park, Building #3   Tel Aviv, 61131   Israel   Phone: +972-3-645-8414   EMail: dromasca@avaya.com   Eugene Golovinsky   EMail: gene@alertlogic.netSiddiqui, et al.            Standards Track                    [Page 35]

RFC 4710                    RAQMON Framework                October 2006Full Copyright Statement   Copyright (C) The Internet Society (2006).   This document is subject to the rights, licenses and restrictions   contained inBCP 78, and except as set forth therein, the authors   retain all their rights.   This document and the information contained herein are provided on an   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS   OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET   ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.Intellectual Property   The IETF takes no position regarding the validity or scope of any   Intellectual Property Rights or other rights that might be claimed to   pertain to the implementation or use of the technology described in   this document or the extent to which any license under such rights   might or might not be available; nor does it represent that it has   made any independent effort to identify any such rights.  Information   on the procedures with respect to rights in RFC documents can be   found inBCP 78 andBCP 79.   Copies of IPR disclosures made to the IETF Secretariat and any   assurances of licenses to be made available, or the result of an   attempt made to obtain a general license or permission for the use of   such proprietary rights by implementers or users of this   specification can be obtained from the IETF on-line IPR repository athttp://www.ietf.org/ipr.   The IETF invites any interested party to bring to its attention any   copyrights, patents or patent applications, or other proprietary   rights that may cover technology that may be required to implement   this standard.  Please address the information to the IETF at   ietf-ipr@ietf.org.Acknowledgement   Funding for the RFC Editor function is provided by the IETF   Administrative Support Activity (IASA).Siddiqui, et al.            Standards Track                    [Page 36]

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