BGP Extended Community for QoS Marking
draft-knoll-idr-qos-attribute-14

#x27; flag.

5.3.  IP Prefix Aggregation

   Several IP prefixes of different IP prefix originating ASes MAY be
   aggregated to a shorter IP prefix in transit ASes.  If the original
   Class Sets of the aggregated prefixes are identical, the aggregate
   will use the same Set. In all other cases, the resulting IP prefix
   aggregate is handled the same as if the transit AS were the
   originating AS for this aggregated prefix.  The transit AS provider
   MAY care for AS internal mechanisms, which map the signalled
   aggregate QoS Class Set to the different original Class Sets in the
   internal forwarding path.

   In case of IP prefix aggregation with different QoS Class Sets, the
   'Aggregation (A)' flag of each QoS Marking community within the Set
   MUST be set to '1'.

6.  Confidentiality Considerations

   The disclosure of confidential AS intrinsic information is of no
   concern since the signalled marking for QoS class encodings can be
   adopted prior to the UPDATE advertisement of the IP prefix
   originating AS.  This way, a distinction between internal and
   external QoS Class Sets can be achieved.  AS internal cross-layer
   marking adaptation and policy based update filtering allows for
   consistent QoS class support despite made up QoS Class Set and
   encoding information within UPDATE advertisements.  In case of such
   policy hiding strategy, the required AS internal ingress and egress
   adaptation SHALL be done transparently without explicit "Active
   Marking" and 'R' flag signalling.

7.  IANA Considerations

   This document defines a new BGP Extended Community, which includes a
   "Technology Type" field.  Section 4.3 enumerates a number of popular
   technologies.  This list is expected to suffice for first
   implementations.  However, future or currently uncovered technologies
   may arise, which will require an extended "Technology Type"
   enumeration list administered by IANA.

   A new extended community QoS Marking community is defined, which has
   been assigned a Type value of 0x04 for a transitive and 0x44 for a

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   non-transitive usage.

8.  Security Considerations

   This extension to BGP does not change the underlying security issues
   inherent in the existing BGP.

   Malicious signalling behaviour of QoS Marking community advertising
   ASes can result in misguided neighbours about non existing or
   maliciously encoded Class Sets.  Removal of QoS Marking community
   Sets leads to the current best effort interconnection, which is no
   stringent security concern.

   The IP prefix originating AS MAY place a copy of its marking
   information into the Internet Routing Registry (IRR) for global
   reference.

   The strongest threat is the advertisement of numerous very fine
   grained Class Sets, which could limit the scalability of this
   approach.  However, neighbouring ASes are free to set the ignore flag
   of single communities or to stop processing the QoS Marking
   communities of a certain routing advertisement, once a self-set
   threshold has been crossed.  By means of this self defence mechanism
   it should not be possible to crash neighbouring peers due to the
   excessive use of the new community.

9.  References

9.1.  Normative References

   [IANA_EC]  IANA, "Border Gateway Protocol (BGP) Data Collection
              Standard Communities", June 2008,
              <http://www.iana.org/assignments/
              bgp-extended-communities>.

   [RFC1997]  Chandrasekeran, R., Traina, P., and T. Li, "BGP
              Communities Attribute", RFC 1997, August 1996.

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

   [RFC3140]  Black, D., Brim, S., Carpenter, B., and F. Le Faucheur,
              "Per Hop Behavior Identification Codes", RFC 3140,
              June 2001.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway

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              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC4360]  Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended
              Communities Attribute", RFC 4360, February 2006.

   [RFC5543]  Ould-Brahim, H., Fedyk, D., and Y. Rekhter, "BGP Traffic
              Engineering Attribute", RFC 5543, May 2009.

   [RFC5575]  Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
              and D. McPherson, "Dissemination of Flow Specification
              Rules", RFC 5575, August 2009.

9.2.  Informative References

   [I-D.boucadair-qos-bgp-spec]
              Boucadair, M., "QoS-Enhanced Border Gateway Protocol",
              draft-boucadair-qos-bgp-spec-01 (work in progress),
              July 2005.

   [I-D.jacquenet-bgp-qos]
              Cristallo, G., "The BGP QOS_NLRI Attribute",
              draft-jacquenet-bgp-qos-00 (work in progress),
              February 2004.

   [I-D.knoll-idr-cos-interconnect]
              Knoll, T., "BGP Class of Service Interconnection",
              draft-knoll-idr-cos-interconnect-12 (work in progress),
              May 2014.

   [I-D.liang-bgp-qos]
              Benmohamed, L., "QoS Enhancements to BGP in Support of
              Multiple Classes of Service", draft-liang-bgp-qos-00 (work
              in progress), June 2006.

   [I-D.zhang-idr-bgp-extcommunity-qos]
              Zhang, Z., "ExtCommunity map and carry TOS value of IP
              header", draft-zhang-idr-bgp-extcommunity-qos-00 (work in
              progress), November 2005.

   [MIT_CFP]  Amante, S., Bitar, N., Bjorkman, N., and others, "Inter-
              provider Quality of Service - White paper draft 1.1",
              November 2006,
              <http://cfp.mit.edu/docs/interprovider-qos-nov2006.pdf>.

Appendix A.  QoS Marking Example

   The example AS is advertising several IP prefixes, which experience

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   equal QoS treatment from AS internal networks.  The IP packet
   forwarding policy within this originating AS defines e.g. 3 traffic
   classes for IP traffic (DSCP1, DSCP2 and DSCP3).  These three classes
   are also consistently taken care of within a TC bit supporting MPLS
   tunnel forwarding.  The BGP UPDATE message for the announced IP
   prefixes will contain the following QoS Marking community Set
   together with the IP prefix NLRI.
   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 0 0|1 0 1 1 1 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 0 0 0|0 0 1 0 1 1 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 1 0 1|0 0 0 0 0 1 0 1|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0|0 0 1 0 1 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 0 1 0|0 0 0 0 1 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 0 1|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 1|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|0 1 0 0 1 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 0 1 0|0 0 0 1 0 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 1 0 0 0 0 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |0 0 0 0 0 0 1 0|0 0 0 0 0 0 1 0|0 0 0 0 0 0 0 0|
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  The class set as well as the example encodings are arbitrarily chosen.

                                 Figure 5

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Author's Address

   Thomas Martin Knoll
   Chemnitz University of Technology

   Email: thomas.m.knoll@gmail.com

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