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Versions: (draft-bertz-dime-congestion-flow-attributes) 00 01 02 RFC 7660

Diameter Maintenance and Extensions (DIME)                      L. Bertz
Internet-Draft                                                S. Manning
Intended Status: Proposed Standard                                Sprint
Expires: December 1, 2015                                   B. Hirschman
                                                               July 2015


               Diameter Congestion and Filter Attributes
           draft-ietf-dime-congestion-flow-attributes-02.txt

Abstract

   This document defines optional Diameter attributes that can be used
   to help manage networks that use Explicit Congestion Notification
   (ECN) or Diameter traffic filters.  These new attributes allow for
   improved data traffic identification, support of ECN and minimize
   Diameter filter administration.

   RFC 5777 defines a Filter-Rule Attribute Value Pair (AVP) that
   accommodates extensions for classification, conditions and actions.
   It however, does not support traffic identification for packets using
   Explicit Congestion Notification as defined in RFC 3168 and does not
   provide specific actions when the flow(s) described by the Filter-
   Rule are congested.

   Further, a Filter-Rule can describe multiple flows but not the exact
   number of flows. Flow count and other associated data (e.g. packets)
   are not captured by Accounting applications, leaving administrators
   without useful information regarding the effectiveness or
   appropriateness of the filter definition.

   The optional attributes defined in this document are forward and
   backwards compatible with RFC 5777.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."



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   This Internet-Draft will expire on December 1, 2015.

Copyright Notice

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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Terminology and Abbreviations  . . . . . . . . . . . . . . . .  4
   3.  ECN-IP-Codepoint, Congestion-Treatment and Filter Attributes .  4
     3.1.  ECN-IP-Codepoint AVP . . . . . . . . . . . . . . . . . . .  4
     3.2.  Congestion-Treatment AVP . . . . . . . . . . . . . . . . .  5
     3.3.  Flow-Count AVP . . . . . . . . . . . . . . . . . . . . . .  5
     3.4.  Packet-Count AVP . . . . . . . . . . . . . . . . . . . . .  5
   4.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . .  6
     4.1.  AVP Codes  . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  Examples . . . . . . . . . . . . . . . . . . . . . . . . . . .  6
     5.1. Classifier Example  . . . . . . . . . . . . . . . . . . . .  6
     5.2. Diameter Credit Control (CC) with Congestion Information  .  7
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . .  8
   7.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . .  9
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . .  9
     8.1.  Normative References . . . . . . . . . . . . . . . . . . .  9
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  9
































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1.  Introduction

   Two optional Explicit Congestion Notification (ECN) [RFC3168] related
   AVPs are specified in this document.  The first AVP provides direct
   support for filtering ECN marked traffic [RFC3168] and the second AVP
   provides the ability to define alternate traffic treatment when
   congestion is experienced.

   This document also defines two optional AVPs, Flow-Count and Packet-
   Count, used for conveying flow information within the Diameter
   protocol [RFC6733].  These AVPs were found to be useful for a wide
   range of applications.  The AVPs provide a way to convey information
   of the group of flows described by the Filter-Rule, IPFilterRule or
   other Diameter traffic filters.

   The semantics and encoding of all AVPs can be found in Section 3.

   Such AVPs are, for example, needed by some congestion management
   functions to determine the number of flows congested or used by
   administrators to determine the impact of filter definitions.

   Additional parameters may be defined in future documents as the need
   arises.  All parameters are defined as Diameter-encoded Attribute
   Value Pairs (AVPs), which are described using a modified version of
   the Augmented Backus-Naur Form (ABNF), see [RFC6733].  The data types
   are also taken from [RFC6733].

2.  Terminology and Abbreviations

   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 [RFC2119].

3.  ECN-IP-Codepoint, Congestion-Treatment and Filter Attributes

3.1.  ECN-IP-Codepoint AVP

   The ECN-IP-Codepoint AVP (AVP Code TBD1) is of type Enumerated and
   specifies the Explicit Congestion Notification codepoint values to
   match in the IP header.

   Value | Binary | Keyword                            | References
   -----------------------------------------------------------------
   0     | 00     | Non-ECT (Not ECN-Capable Transport)| [RFC3168]
   1     | 01     | ECT(1) (ECN-Capable Transport)     | [RFC3168]
   2     | 10     | ECT(0) (ECN-Capable Transport)     | [RFC3168]
   3     | 11     | CE (Congestion Experienced)        | [RFC3168]




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   When this AVP is used for classification in the Filter-Rule it MUST
   be part of Classifier Grouped AVP as defined in RFC5777.

3.2.  Congestion-Treatment AVP

   The Congestion-Treatment AVP (AVP Code TBD2) is of type Grouped.  It
   indicates how to treat traffic IP (5-tuple) flow(s) when congestion
   is detected.  The detection of congestion can be based on the
   reception of IP packets with the Congestion Experience (CE) codepoint
   set (see [RFC3168]) or by any other administratively defined
   criteria.

   A Filter-Rule may contain a Classifier that describes one or many 5-
   tuples per RFC5777.  This treatment applies to all packets associated
   to all 5-tuples (flows) captured by the Filter-Rule.

   If the Congestion-Treatment AVP is absent the treatment of the
   congested traffic is left to the discretion of the node performing
   QoS treatment.

               Congestion-Treatment ::= < AVP Header: TBD2 >
                           { Treatment-Action }
                           [ QoS-Profile-Template ]
                           [ QoS-Parameters ]
                         * [ AVP ]

   Treatment-Action, QoS-Profile-Template and QoS-Parameters are defined
   in RFC5777.  The Congestion-Treatment AVP is an action and MUST be an
   attribute of the Filter-Rule Grouped AVP as defined in RFC5777.

3.3.  Flow-Count AVP

   The Flow-Count AVP (AVP Code TBD3) is of type Unsigned64.

   It indicates the number of protocol specific flows.  The protocol is
   determined by the filter (e.g. IPFilterRule, Filter-Id, etc.).

3.4.  Packet-Count AVP

   The Packet-Count AVP (AVP Code TBD4) is of type Unsigned64.

   It indicates the number of protocol specific packets.  The protocol
   is determined by the filter (e.g. IPFilterRule, Filter-Id, etc.).








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4.  IANA Considerations

4.1.  AVP Codes

   IANA allocated AVP codes in the IANA-controlled namespace registry
   specified in Section 11.1.1 of [RFC6733] for the following AVPs that
   are defined in this document.

   +----------------------------------------------------------------+
   |                                       AVP  Section             |
   |AVP                                    Code Defined Data Type   |
   +----------------------------------------------------------------+
   |ECN-IP-Codepoint                       TBD1 3.1   Enumerated    |
   |Congestion-Treatment                   TBD2 3.2   Grouped       |
   |Flow-Count                             TBD3 3.3   Unsigned64    |
   |Packet-Count                           TBD4 3.4   Unsinged64    |
   +----------------------------------------------------------------+

5.  Examples

   The following examples illustrate the use of the AVPs defined in this
   draft.

5.1. Classifier Example

   The Classifier AVP (AVP Code 511) specified in RFC5777 is a grouped
   AVP that consists of a set of attributes that specify how to match a
   packet.  The addition of the ECN-IP-Codepoint is shown here.

      Classifier ::= < AVP Header: 511 >
                     { Classifier-ID }
                     [ Protocol ]
                     [ Direction ]
                     [ ECN-IP-Codepoint ]
                   * [ From-Spec ]
                   * [ To-Spec ]
                   * [ Diffserv-Code-Point ]
                     [ Fragmentation-Flag ]
                   * [ IP-Option ]
                   * [ TCP-Option ]
                     [ TCP-Flags ]
                   * [ ICMP-Type ]
                   * [ ETH-Option ]
                   * [ AVP ]

   Setting the ECN-IP-Codepoint value to 'CE' would permit the capture
   of CE flags in the Flow.




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   Another Classifier with the ECN-IP-Codepoint value of 'ECT' could be
   specified and, when coupled with the Flow-Count AVP, reports the
   number of ECT capable flows.

5.2. Diameter Credit Control (CC) with Congestion Information

   Diameter nodes using Credit Control can use the Congestion-Treatment
   AVP to trigger specific actions when congestion occurs.  This is
   similar to the Excess-Treatment Action.  The ability to detect when
   congestion occurs is specific to the AVPs in the Filter-Rule and
   Diameter Client and is no different than how 'Excess' can be
   determined for Excess-Treatment.  If conditions associated with
   Excess-Treatment [RFC5777] or Congestion-Treatment has occurred
   Diameter Clients may autonomously send Credit Control Requests (CCRs)
   during the Service Delivery session as interim events.  This is shown
   in Figure 1.


                              Service Element
        End User            (CC Client)                        CC Server
           |                     |                                  |
           |(1) Service Request  |                                  |
           |-------------------->|                                  |
           |                     |(2) CCR (Initial,                 |
           |                     |    QoS-Resources(QoS-Desired))   |
           |                     |--------------------------------->|
           |                     |(3) CCA (Granted-Units,           |
           |                     |    QoS-Resources(QoS-Authorized))|
           |                     |<---------------------------------|
           |(4) Service Delivery |                                  |
           |<------------------->|                                  |
           |              (5) Congestion Detected                   |
           |              (6) Congestion Treatment Occurs           |
           |                     |(7) CCR (Termination, Used-Units, |
           |                     |    Flow-Count, Packet-Count,     |
           |                     |    QoS-Resources(QoS-Delivered)) |
           |                     |--------------------------------->|
           |                     |(8) CCA                           |
           |                     |<-------------------------------->|
           |                     |                                  |
           |                     |                                  |
           |(9) End of Service   |                                  |
           |-------------------->|                                  |
           |                     |(10)CCR (Termination, Used-Units, |
           |                     |    Flow-Count, Packet-Count,     |
           |                     |    QoS-Resources(QoS-Delivered)) |
           |                     |--------------------------------->|
           |                     |(11) CCA                          |



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           |                     |<---------------------------------|

   Figure 1: Example of a Diameter Credit Control with Congestion
   Information

   The 'Used-Service-Units' described in RFC5777 examples is customarily
   a Service-Units, Time-Units or Byte-Count AVP.  This is insufficient
   to represent network state and does not differentiate between
   throughput and good-put (good or quality throughput) even though the
   filters may imply good or poor throughput.

   Flow-Count and Packet-Count AVPs defined in this document could be
   sent with a CCR when the triggering event is related to Congestion-
   Treatment.  This provides the CC Server with a better view of the
   type of congested traffic for improved decision making and charging.
   Sending such AVPs under any condition permits rudimentary traffic
   profiling regardless of network conditions.  For instance, low byte
   per packet counts is indicative of web traffic and high byte counts
   per packet with a small number of flows may be indicative of video
   traffic.  Enriched reporting described here provides relief from Deep
   Packet Inspection load and loss of information as traffic becomes
   increasingly encrypted.

   Some services, e.g. Streaming Services, limit the number of flows,
   Flow-Count, as opposed to other Units, i.e. Byte-Count.  In such a
   case the Flow-Count AVP may be used in place of Service-Units.

6.  Security Considerations

   This document describes an extension of RFC5777 that introduces a new
   filter parameter applied to ECN as defined by [RFC3168].  It also
   defines a new Grouped AVP that expresses what action to take should
   congestion be detected.  The Grouped AVP reuses attributes defined in
   RFC5777.  As these are extensions to RFC 5777, they do not raise new
   security concerns.

   The Flow-Count and Packet-Count AVPs can be provided in conjunction
   with customary AVPs, e.g. Bytes, Time, Service Units, during
   Accounting activities as described in the base protocol [RFC6733] or
   other Diameter applications.  These new AVPs provide more information
   that can be privacy sensitive.  The privacy sensitivity is directly
   related to traffic captured by Filters and associated reports.
   Narrow filtering, which creates the highest level of privacy
   sensitivity, is too resource intensive to be widely applied on large
   networks.  Paradoxically, improving reporting information lessens the
   depth of inspection required to characterize traffic for many
   congestion management activities as noted in Section 5.2.




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   If an administrator can provide congestion actions without the need
   to report them to a Diameter application they should use the
   Congestion-Treatment AVP which also reduces Diameter traffic during
   congestion events.

   The security considerations of the Diameter protocol itself have been
   discussed in RFC 6733 [RFC6733].  Use of the AVPs defined in this
   document MUST take into consideration the security issues and
   requirements of the Diameter base protocol.

7.  Acknowledgements

   We would like to thank Avi Lior for his guidance and feedback during
   the development of this specification.

8.  References
8.1.  Normative References

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

   [RFC3168]  Black, D., Floyd, S., and K. Ramakrishnan, "The Addition
              of Explicit Congestion Notification (ECN) to IP", RFC
              3168, September 2001.

   [RFC6733]  Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
              "Diameter Base Protocol", RFC 6733, October 2012.

   [RFC5777]  Korhonen, J., Tschofenig, H., Arumaithurai, M., Lior, A.
              and Jones, M. Ed., "Traffic Classification and Quality of
              Service (QoS) Attributes for Diameter", RFC 5777, February
              2010.

Authors' Addresses


              Lyle Bertz
              Sprint
              6220 Sprint Parkway
              Overland Park, KS 66251
              United States

              EMail: lyleb551144@gmail.com

              Serge Manning
              Sprint
              6220 Sprint Parkway
              Overland Park, KS 66251



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              United States

              EMail: sergem913@gmail.com

              Brent Hirschman

              EMail: Brent.Hirschman@gmail.com












































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