Internet Draft                                            Anwar Siddiqui
draft-ietf-rmonmib-raqmon-framework-06.txt                    Avaya Inc.
Category: Standards Track                                  Dan Romascanu
Expires January 2005                                               Avaya
                                                       Eugene Golovinsky
                                                            BMC Software
                                                             8 July 2004

                Real-time Application Quality of Service
                     Monitoring (RAQMON) Framework


Status of this Memo

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   applicable patent or other intellectual property right (IPR) claims
   of which he or she is aware have been or will be disclosed, and any
   of which he or she becomes aware will be disclosed, in accordance
   with Section 6 of RFC 3668.

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Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   There is a need to monitor end devices such as IP Phones, Pagers,
   Instant Message Clients, Mobile Phones, and various other hand-held
   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



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   using the Simple Network Management Protocol (SNMP).  This memo
   defines the framework, architecture, relevant metrics, and transport
   requirements for real-time quality of service monitoring of
   applications.

   Distribution of this memo is unlimited.

Table of Contents

   Status of this Memo..................................................1
   Abstract.............................................................1
   1 Introduction.......................................................3
   2 RAQMON Functional Architecture.....................................5
   3 RAQMON Operation in Congestion-Safe Mode..........................12
   4 Measurement Methodology...........................................14
   5 Metrics pre-defined for the BASIC Part of the RAQMON PDU..........15
   6 Report Aggregation and Statistical Data processing................24
   7 Keeping Historical Data and Storage...............................25
   8 Acknowledgements..................................................25
   9 Security Considerations...........................................25
   10 Normative References.............................................28
   11 Informative References ..........................................28
   Authors' Addresses..................................................30
   Full Copyright Statement............................................30



























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1. 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 hand-helds 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 like
   these, and allows this information to be integrated using the
   familiar RMON family of specifications via SNMP.

   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 quality of service (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 Delay, Jitter, Packet Loss, and the type of codec used
   in a call.  Behavior of network protocols like 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
   also influence the performance of a VoIP call.

   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 Real Time
   Application QoS Monitoring (RAQMON) Framework offers a mechanism to



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   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, it's the applications at these devices that 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
   standardizes the following:

      a. A set of basic metrics sent as reports between the RAQMON
         entities using existing Internet Transport Protocols such as
         TCP, SIP, or SNMP and 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, and a set of metrics and informational 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 [RAQMON-PDU] memo provides definitions of syntactical PDU
   structure and use case scenarios of transmission of such PDUs over
   the Simple Network Management Protocol (SNMP).




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   The RAQMON MIB [RAQMON-MIB] 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, pagers, application clients like instant message
   clients, soft phones in PCs, etc. are envisioned to act as RDSs
   within the RAQMON Framework.
























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   +----------------------+        +---------------------------+
   |    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 RTCP APP Packet or SNMP Notifications
                                               |
                  +----------------------------+
                  |                            |
                  |/                           |/
     +------------------+      +------------------+       +------------------+
     |RAQMON Report     |  ..  |RAQMON Report     |       |Network Management|
     |Collector (RRC) #n|      |Collector (RRC) #1|<--5-->|    Application   |
     +------------------+      +------------------+       +------------------+


   Figure 1 - RAQMON Framework.

      (1) Communication Session between applications

      (2) Context-Sensitive Metrics

      (3) Device State Specific Metrics

      (4) 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.  A
   RAQMON Report Collector (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.



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   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 each communication session.  The RDS entities capture QoS
   attributes of such communication sessions and report them within a
   RAQMON "reporting session".

   A 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, a RAQMON Data Source (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.

   A RAQMON Data Source (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.  If two IP Phone users for example
   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.



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2.1.2 RAQMON Data Source (RDS) Requirements

      1. RAQMON Data Sources SHALL gather reports from multiple
         applications residing in that device and of 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 support the basic set of metrics
         defined within the RAQMON informational model.

      3. RAQMON Data Sources MUST support at least one of the standard
         mappings on transport protocols.


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.

   A RDS can use one or more of the following mechanisms to gain access
   to configuration parameters:

      -  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
      -  RDS is manually configured using command line interface (CLI),
         Telephone User Interface (TUI) etc.

   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



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   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 application level
   specification in RRC is beyond the scope of this memo.

2.2.2 RAQMON Report Collector (RRC) Requirements

      1. RAQMON Report Collectors MUST support at least one of the
         standard mappings of the RAQMON informational model with the
         purpose of receiving RAQMON reports from RAQMON Data Sources
         (RDS).

      2. RAQMON Report Collectors MUST implement session time out
         mechanisms to assume end of reporting for RDSs that have been
         out of reporting for a reasonable duration of time. Such time
         out parameters SHOULD be configurable in vendor
         implementations, programmable at deployment.


      3. RAQMON Report Collectors MUST support the RAQMON MIB. 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.



2.3 Informational Model and RAQMON Protocol Data Unit (PDU)

2.3.1. RAQMON Informational Model


   RAQMON defines a set of basic metrics that characterize the Quality
   of Service (QoS) of applications, as reported by RAQMON Data Sources.



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   This basic set of metrics is defined in Section 5 of this memo.

   New 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.

   The RAQMON Informational 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 in Section 2.4 of
   this memo.

   Though architected conceptually as a single Protocol Data Unit, the
   RAQMON PDU is functionally divided into two different parts.  They
   are the BASIC Part, and the Application Specific Extensions, required
   for vendor specific extensions.  Structure of Management Information
   (SMI) Network Management Private Enterprise Codes are being used to
   indicate the owner of the definition of a specific section of the
   RAQMON PDU. These codes are currently maintained by the Internet
   Assigned Numbers Authority (IANA) at
   http://www.iana.org/assignments/enterprise-numbers. Depending on the
   respective transport, the enterprise code may be implicitly carried
   by the protocol (i.e. SNMP OIDs), or will be carried in explicit
   fields.

   The BASIC Part of the RAQMON PDU:
      The BASIC part of the RAQMON PDU trails behind 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 in Section 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 sub-set of the parameters listed in Section
      5. There is no need to carry all metrics in every PDU, moreover it
      is RECOMMENDED that static or pseudo-static metrics which do not
      change, or seldom change for a given session or application will
      be send only when the session or application are initiated, and



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      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-, device-, etc. 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 Application part of the RAQMON PDU trails behind
      a vendor's SMI Network Management Private Enterprise Codes found
      in http://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 would require 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 tenth, many hundreds, more) of RDSs, scalability
         of the transport protocol is REQUIRED.

      3. Congestion safety - as per [RFC2914] - see also Section 3

      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 is REQUIRED

      5. NAT Friendly - The transport protocol SHOULD comply with



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         [RFC3235], so that an RDS could communicate with an RRC through
         a Firewall/Network Address Translation device.

      6. The transport protocol MAY implement session time out
         mechanisms to assume end of reporting for RDSs that have been
         out of reporting for a reasonable duration of time.  Such time
         out 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 [RAQMON-PDU] describe how the PDU is transported
   over existing application level protocols the Simple Network
   Management Protocol (SNMP).



3.  RAQMON Operation in Congestion-Safe Mode

   RAQMON PDUs can be transmitted over multiple transport protocols,
   including UDP, DCCP and TCP.  The RAQMON Framework will be congestion
   safe, if a RAQMON PDU is transported over TCP.  To ensure congestion
   safety, clearly the best thing to do is to use a transport protocol
   like TCP or Stream Control Transmission Protocol (SCTP).  If this is
   not feasible, it may be necessary to fall back on UDP.  A RAQMON PDU
   from RDS to RRC either over RTCP or SNMP allows the use of UDP for
   transport, which might lead to network congestion under heavy network
   load.

   One solution to the congestion awareness problem could have been to
   deprecate UDP entirely for RAQMON.  Though RAQMON PDU can be
   transported over TCP, either SNMP or RTCP over TCP are not commonly
   practiced in practical deployments.  Moreover there are legitimate
   places where UDP appears to be quite useful such as tiny mobile
   phones, pagers, various other hand held computing devices, RAQMON



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   Report Collectors where extremely high-volume RDSs connect over
   dedicated networks, etc.

   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 PDU 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 would 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.  As a worst-
         case scenario, if the RDSs enforce an administrative policy
         where the maximum PDU transmission rate is no more 1 RAQMON PDU
         every 2 minutes, a UDP based implementation can be as
         congestion safe as a TCP based implementation.  Such policies
         can be enforced while configuring an RDS.

      2. Retransmission timers with back offs: 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 example if RAQMON PDU is
         transported using SNMP INFORM PDUs over UDP, a SNMP response
         from the RRC SHOULD be processed by the RDS to implement this
         mechanism.




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         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 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.

         Retransmission timers with back offs will not be useful if
         RAQMON PDUs are transported over RTCP/UDP; RRCs do not provide
         any acknowledgement that RDS can rely on.

      3. By restricting transmission to maximum transmission unit (MTU)
         Size: A 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 the same RAQMON reporting session with exactly the same
         Network Time Protocol (NTP) 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.

4.  Measurement Methodology

   It is not the intent of this document to recommend a methodology to
   measure any of the QoS parameters defined in Table 1.  Measurement



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   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.  It 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
   [RAQMON-PDU] 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 [RAQMON-PDU] specification.

5.1  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 allocated address as defined in [RFC1918].

   It is expected that the Data Source Address (DA) would remain



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   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 Source Address (RA)

   The Receiver Source Address (RA) takes the same form as the Data
   Source Address (DA) but represents the Receiver's Source Address.  In
   a communication session the reporting RDSs SHOULD fill in the other
   party's address as a Receiver Source Address.  Like the Data Source
   Address, this could be either a globally unique IPv4 or IPv6 address,
   or a privately allocated address as defined in [RFC1918].

   It is expected that the Receiver Source Address (RA) 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.

5.3  Data Source Name (DN)

   The 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] and Section 2.1 of [RFC1123].  Examples are
        "big-guy@ip-phone.avaya.com" or "big-guy@135.8.45.178" for a
        multi-user system.  On a system with no user name, an example
        would be "ip-phone4630.bigcompany.com".  It is RECOMMENDED that
        the standard host's numeric address not be reported via the DN
        parameter, as the Data Source Address (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.  It is
        recommended that the phone number SHOULD be formatted with the
        plus sign replacing the international access code.  Example:
        "+88 02 123 45678" for a number in Bangladesh.

   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 to ensure an efficient usage of network resources.


5.4  Receiver Name (RN)




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   The Receiver Name (RN) takes the same form as Data Source Name (DN),
   but represents the Receiver's name.  In a communication session, an
   application should supply as a Receiver Name 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 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.

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.

5.7  Session Setup Date/Time

   This parameter gives the wall clock time when the RAQMON packet was
   sent.  This information is needed by the RRC.  Wall clock time
   (absolute 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].

5.8  Session Setup Delay

   The Session Setup Delay metric reports the duration of time required
   by a network communication controller to set up a media path between
   the communicating entities or end devices.  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.  However as these
   definitions are very specific to the type of system used and the
   implementation details of such systems, no claim is made on the
   appropriateness of the definition presented here.  For any particular



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   application it is left to the implementers to define Session Setup
   Delay appropriately.

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 pick up and call termination, including session
   setup time.

5.10  Session Setup Status

   The Session Setup Status parameter 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.  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.

5.11  Round Trip End-to-End Delay

   The Round Trip End-to-End Delay [RFC3550], [RFC2681], [RFC2679] is a
   key metric for Application QoS Monitoring.  Some applications do not
   perform well (or at all) if end-to-end delay between hosts is large
   relative to some threshold value.  Erratic variation in delay makes
   it difficult (or impossible) to support many real-time applications
   such as Voice over IP, Video over IP, Fax over IP etc.

   There are many measurement methodologies available for this
   parameter, but it is intended to capture the End-to-End delay as
   observed by the IP device at the application layer pertaining to a
   specific operational environment.  Wherever possible, it is
   RECOMMENDED that specific application layer delays like play-out
   delay, packet-sequencing delays, and coding/decoding delays be added
   to network transport delay to report End-to-End delay.

   The End-to-End delay of the underlying transport network can be
   measured using various methodologies as described in [RFC2681],
   [RFC2679], [RFC3550] depending on the application needs.  It is left
   up to implementers to select appropriate IETF and ITU methodologies
   for the measurement of End-to-End Delays for a specific application.

5.12  One Way End-to-End Delay




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   The One Way End-to-End Delay [RFC2679] metric reports the End-to-End
   delay encountered by traffic from the source application for the
   destination application.  One Way Delay measurements identified by
   the IP Performance Metrics (IPPM) Working Group [RFC2679] could be
   used to measure one-way end-to-end 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.  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 trasnfer more) versus Packet-over-SONET
   (synchronous optical network)).

   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, rather than
   the direction in which acknowledgements travel.

   In quality-of-service (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.

   It is outside the scope of this document to say precisely which
   applications would use one-way end-to-end delay.  One-way end-to-end
   delay is expressed in the same units as round trip end-to-end Delay.

5.13  Jitter

   The variation in packet delay is called "jitter" [RFC 3393].  The
   definition of jitter is context sensitive and measurement specific.

   One important use of jitter is the sizing of play-out buffers for
   applications requiring the regular delivery of packets (for example,
   voice or video play-out).  Other uses of a delay variation metric
   are, for example, 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 process at a given link or a
   combination of links.  [RFC 3393] provides guidance to several
   absolute jitter parameters.

   An alternative, but related, way of computing an estimate of jitter



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   is given in [RFC3550].  The selection function there is implicitly
   consecutive packet pairs, and the "jitter estimate" is computed by
   taking the absolute values of the IP packet delay variation sequence
   (ipdv) as defined in RFC 3393 and applying an exponential filter with
   parameter 1/16 to generate the estimate (i.e., j_new = 15/16* j_old +
   1/16*j_new).  Inter-arrival jitter provides a short-term measure of
   congestion [RFC3550].  The jitter measure indicates congestion before
   it leads to packet loss.

5.14  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.
   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 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 session this
   counter represents the number of signaling session related packets
   that have been received which 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.

   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 can be one of the ways to
   measure media related application packets received, applicable for
   the scenarios described above.

5.15  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
   up until the time this RAQMON PDU was generated.  Similar to total
   number of application packets parameter in section 5.14, this count
   is a snapshot in time.  Depending on 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.



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5.16  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.  This metric could be measured in different ways,
   including the methodology described by [RFC3550].

5.17  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.  This metric could be measured in different ways,
   including the methodology described by [RFC3550].

5.18  Cumulative Application Packet Loss

   The packet loss metric SHOULD indicate loss associated with the
   network environment as well as local device losses over time.  Packet
   loss by the underlying transport network can be measured using
   various methodologies, e.g. as described in [RFC2680], [RFC3550], and
   local device level packet losses should be captured by the local
   device-specific algorithms.


5.19  Packet loss in Fraction

   The Packet loss in Fraction statistic represents packet loss as
   defined above, but expressed as a percentage of the total traffic,
   since the last report.


5.20  Source Payload Type

   The Source Payload Type reports payload formats (e.g. media
   encodings) 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 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 then necessary to ensure an efficient usage



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   of network resources.


5.21  Destination Payload Type

   The Destination 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].
   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, to ensure an efficient
   usage of network resources.


5.22  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 802.1p standard.  Details on these
   can be found in IEEE 802.1Q "Virtual Bridged LAN" specifications.
   802.1p has been incorporated into ISO/IEC 15802-3 1998 [IEEE802.1Q].
   The Source Layer 2 Priority RAQMON field indicates what Layer 2
   values were used by 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. RDSs SHOULD avoid sending these parameters
   within RAQMON reports too often to ensure an efficient usage of
   network resources.

5.23  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, while 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.



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   The Source TOS/DSCP value is expected to remain constant for the
   duration of a session. RDSs SHOULD avoid sending these parameters
   within RAQMON reports too often to ensure an efficient usage of
   network resources.

5.24  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 any Layer 2 technologies
   like IEEE 802.1p/Q or priority queuing etc.

   The Destination Layer 2 Priority value is expected to remain constant
   for the duration of a session. RDSs SHOULD avoid sending these
   parameters within RAQMON reports too often to ensure an efficient
   usage of network resources.


5.25  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], Type Of Service (TOS) [RFC2474],
   [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. RDSs SHOULD avoid sending these parameters
   within RAQMON reports too often to ensure an efficient usage of
   network resources.

5.26  CPU Utilization in Fraction

   This parameter captures the IP Device CPU usage which may have very
   critical implications for QoS of an end device.  It is computed over
   the session duration, and corresponds to the percentage of that time
   that the CPU was busy.

5.27  Memory Utilization in Fraction

   This parameter captures the IP Device Memory usage which may have
   very critical implications for QoS of an end device.  It is computed
   over the session duration, and corresponds to the average percentage
   of memory in use during that time.



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5.28  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.

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 is 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
   [30].  One should use APM and TPM MIBs to aggregate parameters based
   on protocols (e.g. performance of HTTP, RTP) or based on applications
   (e.g. performance of VoIP, Video Applications).

   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



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            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 or an
         RTCP BYE packet.  The aggregated data could be made available
         using the RAQMON MIB as Mean, Max or Min entries and be 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.

      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.  Acknowledgements

   The authors would like to thank Randy Presuhn for the extensive and
   detailed review that he performed on this memo from all possible
   aspects - technical content, editorial consistency, syntax, and
   spelling. The authors would also like to thank Mahalingam Mani,
   Steven Waldbusser, Alan Clark, Robert Cole, and Itai Zilbershtein for
   interesting discussions and direct contributions in this problem
   space.


9.  Security Considerations

   Security considerations associated with the RAQMON Framework are
   discussed below, and in greater detail in other RAQMON memos as is
   appropriate.



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9.1  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;

   Consequently, threats based on unauthorized disclosure or
   modification of payloads or headers will have to be assumed.

9.2  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



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         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 Encyrption
         Standard (AES), etc.

      3. Protection from denial of service 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 and 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 TBD reporting interval.  Sessions shorter than
         that should be stored in the RDS and will be reported only
         after that interval has expired.

9.3  RAQMON Security Model

   The RAQMON architecture permits the use of a wide range of 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.

      2. A good cryptographic security protocol always has an associated
         key management protocol. Use of transport protocol security
         relies on its key management, rather than requiring 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.




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      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.



10.  Normative References

   [RFC791]     Postel, J., "Internet Protocol", STD 5, RFC 791,
                September 1981.

   [RFC2119]    Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2819]    Waldbusser, S., "Remote Network Monitoring Management
                Information Base", STD 59, RFC 2819, May 2000.

   [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", RFC 3550, 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", RFC 1305,
                March 1992.

   [RFC1812]    Baker, F., "Requirements for IP Version 4 Routers",
                RFC1812, June 1995.




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   [RFC1918]    Rekhter, Y., Moskowitz, R., Karrenberg, D., de Groot,
                G., and E. Lear, "Address Allocation for Private
                Internets", BCP 5, RFC 1918, March 1996.

   [RFC2474]    Nicholas, K., Blake, S., Baker, F, and D. Black,
                "Definition of the Differentiated Services Field (DS
                Field) in the IPv4 and IPv6 Headers", RFC2474, December
                1998.

   [RFC2475]    Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
                and W. Weiss, "An Architecture for Differentiated
                Services", RFC2475, 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.

   [RFC2914]    Floyd, S., "Congestion Control Principles", BCP 41, RFC
                2914, September 2000.

   [RFC3235]    Senie, D., "Network Address Translator (NAT)-Friendly
                Application Design Guidelines", RFC3235, January 2002.

   [RFC 3393]   Demichelis, C. and P. Chimento, "IP Packet Delay
                Variation Metric for IP Performance Metrics (IPPM)", RFC
                3393, November 2002.

   [RFC3551]    Schulzrinne, H. and S. Casner, "RTP Profile for Audio
                and Video Conferences with Minimal Control", STD 65, RFC
                3551, July 2003.

   [RFC3711]    Bauer, M., McGrew, D., Naslund, M., Carrara, E., and K.
                Norrman, "The Secure Real-time Transport Protocol
                (SRTP)", RFC 3711, March 2004.

   [RFC3729]    Waldbusser, S., "Application Performance Measurement
                MIB", RFC 3729, March 2004.

   [RAQMON-PDU] Siddiqui, A., Romascanu, D., and E. Golovinsky, "SNMP
                Notification Transport for Real-time Application Quality
                of Service Monitoring (RAQMON) Protocol Data Unit
                (PDU)", Internet-Draft, draft-ietf-raqmon-pdu-06.txt,
                July 2004.



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   [RAQMON-MIB] Siddiqui, A., Romascanu, D., Golovinsky, E., and R.
                Smith, "Real-time Application Quality of Service
                Monitoring (RAQMON) MIB", Internet-Draft, draft-ietf-
                rmonmib-raqmon-mib-04.txt, June 2004.

   [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) [ANSI/IEEE Std 802.1D, 1998 Edition]

Authors' Addresses

   Anwar A. Siddiqui
   Avaya Labs
   307 Middletown Lincroft Road
   Lincroft, New Jersey 07738
   USA
   Tel: +1 732 852-3200
   E-mail: anwars@avaya.com

   Dan Romascanu
   Avaya
   Atidim Technology Park, Building #3
   Tel Aviv, 61131
   Israel
   Tel: +972-3-645-8414
   Email: dromasca@avaya.com

   Eugene Golovinsky
   BMC Software Inc.
   2101 CityWest Boulecard
   Houston, Texas 77042
   USA
   Tel: +1 713 918-1816
   Email: eugene_golovinsky@bmc.com

Full Copyright Statement

   Copyright (C) The Internet Society (2004).  This document is subject
   to the rights, licenses and restrictions contained in BCP 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 CONTRIBUTORS, THE ORGANIZATIONS THEY REPRESENT
   OR ARE 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



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   INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
   WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

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Acknowledgement:

   Funding for the RFC Editor function is currently provided by the
   Internet Society.






















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