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Network Working Group                                       G. Cristallo
Internet Draft                                                   Alcatel
Document: draft-jacquenet-bgp-qos-00.txt                    C. Jacquenet
Category: Experimental                                    France Telecom
Expires August 2004                                        February 2004



                       The BGP QOS_NLRI Attribute
                    <draft-jacquenet-bgp-qos-00.txt>


Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC 2026 [1].

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups. Note that other
   groups may also distribute working documents as Internet-Drafts.
   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".

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   NOTE: a PDF version of this document (which includes the figures
   mentioned in section 7) can be accessed at http://www.mescal.org.

Abstract

   This draft specifies an additional BGP4 (Border Gateway Protocol,
   version 4) attribute, named the "QOS_NLRI" attribute, which aims at
   propagating QoS (Quality of Service)-related information associated
   to the NLRI (Network Layer Reachability Information) information
   conveyed in a BGP UPDATE message.

Table of Contents

   1.      Conventions Used in this Document..........................2
   2.      Introduction...............................................2
   3.      Basic Requirements.........................................3
   4.      The QOS_NLRI Attribute (Type Code tbd*)....................3
   5.      Operation..................................................7
   6.      Use of Capabilities Advertisement with BGP-4...............8
   7.      Simulation Results.........................................8

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   7.1.    A Phased Approach..........................................8
   7.2.    A Case Study..............................................10
   7.3.    Additional Results........................................11
   7.4.    Next Steps................................................12
   8.      IANA Considerations.......................................12
   9.      Security Considerations...................................12
   10.     References................................................13
   11.     Acknowledgments...........................................13
   12.     Authors' Addresses........................................14
   13.     Full Copyright Statement..................................14


1.   Conventions Used in this Document

   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 RFC 2119 [2].

2.   Introduction

   Providing end-to-end quality of service is one of the most important
   challenges of the Internet, not only because of the massive
   development of value-added IP service offerings, but also because of
   the various QoS policies that are currently enforced within an
   autonomous system, and which may well differ from one AS (Autonomous
   System) to another.

   For the last decade, value-added IP service offerings have been
   deployed over the Internet, thus yielding a dramatic development of
   the specification effort, as far as quality of service in IP networks
   is concerned. Nevertheless, providing end-to-end quality of service
   across administrative domains still remains an issue, mainly because:

   - QoS policies may dramatically differ from one service provider to
     another,

   - The enforcement of a specific QoS policy may also differ from one
     domain to another, although the definition of a set of common
     quality of service indicators may be shared between the service
     providers.

   Activate the BGP4 protocol ([3]) for exchanging reachability
   information between autonomous systems has been a must for many
   years. Therefore, disseminating QoS information coupled with
   reachability information in a given BGP UPDATE message appears to be
   helpful in enforcing an end-to-end QoS policy.

   This draft aims at specifying a new BGP4 attribute, the QOS_NLRI
   attribute, which will convey QoS-related information associated to
   the routes described in the corresponding NLRI field of the
   attribute.


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   This document is organized according to the following sections:

   - Section 3 describes the basic requirements that motivate the
     approach,

   - Section 4 describes the attribute,

   - Section 5 elaborates on the mode of operation,

   - Section 6 elaborates on the use of the capabilities advertisement
     feature of the BGP4 protocol,

   - Section 7 depicts the results of a simulation work,

   - Finally, sections 8 and 9 introduce IANA and some security
     considerations, respectively.

3.   Basic Requirements

   The choice of using the BGP4 protocol for exchanging QoS information
   between domains is not only motivated by the fact BGP is currently
   the only inter-domain (routing) protocol activated in the Internet,
   but also because the manipulation of attributes is a powerful means
   for service providers to disseminate QoS information with the desired
   level of precision.

   The approach presented in this draft has identified the following
   requirements:

   - Keep the approach scalable. The scalability of the approach can be
     defined in many ways that include the convergence time taken by the
     BGP peers to reach a consistent view of the network connectivity,
     the number of route entries that will have to be maintained by a
     BGP peer, the dynamics of the route announcement mechanism (e.g.,
     how frequently and under which conditions should an UPDATE message
     containing QoS information be sent?), etc.

   - Keep the BGP4 protocol operation unchanged. The introduction of a
     new attribute should not affect the way the protocol operates, but
     the information contained in this attribute may very well influence
     the BGP route selection process.

   - Allow for a smooth migration. The use of a specific BGP attribute
     to convey QoS information should not constrain network operators to
     migrate the whole installed base at once, but rather help them in
     gradually deploying the QoS information processing capability.

4.   The QOS_NLRI Attribute (Type Code tbd*)

   (*): "tbd" is subject to the IANA considerations section of this
   draft.


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   The QOS_NLRI attribute is an optional transitive attribute that can
   be used:

   1. To advertise a QoS route to a peer. A QoS route is a route that
     meets one or a set of QoS requirement(s) to reach a given (set of)
     destination prefixes. Such QoS requirements can be expressed in
     terms of minimum one-way delay ([4]) to reach a destination, the
     experienced delay variation for IP datagrams that are destined to
     a given destination prefix ([5]), the loss rate experienced along
     the path to reach a destination, and/or the identification of the
     traffic that is expected to use this specific route
     (identification means for such traffic include DSCP (DiffServ Code
     Point, [6]) marking). These QoS requirements can be used as an
     input for the BGP route calculation process,

   2. To provide QoS-related information along with the NLRI information
     in a single BGP UPDATE message. It is assumed that this
     information will be related to the route (or set of routes)
     described in the NLRI field of the attribute.

   From a service provider's perspective, the choice of defining the
   QOS_NLRI attribute as an optional transitive attribute is motivated
   by the fact that this kind of attribute allows for gradual deployment
   of the dissemination of QoS-related information by BGP4: not all the
   BGP peers are supposed to be updated accordingly, while partial
   deployment of such QoS extensions can already provide an added value,
   e.g. in the case where a service provider manages multiple domains,
   and/or has deployed a BGP confederation ([7]).

   This draft makes no specific assumption about the means to actually
   value this attribute, since this is mostly a matter of
   implementation, but the reader is suggested to have a look on
   document [8], as an example of a means to feed the BGP peer with the
   appropriate information. The QOS_NLRI attribute is encoded as
   follows:

         +---------------------------------------------------------+
         | QoS Information Code (1 octet)                          |
         +---------------------------------------------------------+
         | QoS Information Sub-code (1 octet)                      |
         +---------------------------------------------------------+
         | QoS Information Value (2 octets)                        |
         +---------------------------------------------------------+
         | QoS Information Origin (1 octet)                        |
         +---------------------------------------------------------+
         | Address Family Identifier (2 octets)                    |
         +---------------------------------------------------------+
         | Subsequent Address Family Identifier (1 octet)          |
         +---------------------------------------------------------+
         | Network Address of Next Hop (4 octets)                  |
         +---------------------------------------------------------+
         | Flags (1 octet)                                         |

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         +---------------------------------------------------------+
         | Identifier (2 octets)                                   |
         +---------------------------------------------------------+
         | Length (1 octet)                                        |
         +---------------------------------------------------------+
         | Prefix (variable)                                       |
         +---------------------------------------------------------+

   The use and meaning of the fields of the QOS_NLRI attribute are
   defined as follows:

   -  QoS Information Code:

       This field carries the type of the QOS information. The following
       types have been identified so far:

   (0) Reserved
   (1) Packet rate, i.e. the number of IP datagrams that can be
       transmitted (or have been lost) per unit of time, this number
       being characterized by the elaboration provided in the QoS
       Information Sub-code (see below)
   (2) One-way delay metric
   (3) Inter-packet delay variation
   (4) PHB Identifier

   -  QoS Information Sub-Code:

       This field carries the sub-type of the QoS information. The
       following sub-types have been identified so far:

   (0) None (i.e. no sub-type, or sub-type unavailable, or unknown sub-
       type)
   (1) Reserved rate
   (2) Available rate
   (3) Loss rate
   (4) Minimum one-way delay
   (5) Maximum one-way delay
   (6) Average one-way delay

   The instantiation of this sub-code field MUST be compatible with the
   value conveyed in the QoS Information code field, as stated in the
   following table (the rows represent the QoS Information Code possible
   values, the columns represent the QoS Information Sub-code values
   identified so far, while the "X" sign indicates incompatibility).









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            +---------------------------------------+
            |    |  0 |  1 |  2 |  3 |  4 |  5 |  6 |
            +---------------------------------------+
            |  0 |    |    |    |    |    |    |    |
            +---------------------------------------+
            |  1 |    |    |    |    |  X |  X |  X |
            +---------------------------------------+
            |  2 |    |  X |  X |  X |    |    |    |
            +---------------------------------------+
            |  3 |    |  X |  X |  X |  X |  X |  X |
            +---------------------------------------+
            |  4 |    |  X |  X |  X |  X |  X |  X |
            +---------------------------------------+

   -  QoS Information Value:

       This field indicates the value of the QoS information. The
       corresponding units obviously depend on the instantiation of the
       QoS Information Code. Namely, if:

   (a) QoS Information Code field is "0", no unit specified,
   (b) QoS Information Code field is "1", unit is kilobits per second
       (kbps), and the rate encoding rule is composed of a 3-bit
       exponent (with an assumed base of 8) followed by a 13-bit
       mantissa, as depicted in the figure below:

                             0      8       16
                             |       |       |
                             -----------------
                             |Exp| Mantissa  |
                             -----------------

       This encoding scheme advertises a numeric value that is (2^16 -1
       - exponential encoding of the considered rate), as depicted in
       [9].
   (c) QoS Information Code field is "2", unit is milliseconds,
   (d) QoS Information Code field is "3", unit is milliseconds,
   (e) QoS Information Code field is "4", no unit specified.

   -  QoS Information Origin:

       This field provides indication on the origin of the path
       information, as defined in section 4.3.of [3].

   -  Address Family Identifier (AFI):

       This field carries the identity of the Network Layer protocol
       associated with the Network Address that follows. Currently
       defined values for this field are specified in [10] (see the
       Address Family Numbers section of this reference document).



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   -  Subsequent Address Family Identifier (SAFI):

       This field provides additional information about the type of the
       prefix carried in the QOS_NLRI attribute.

   -  Network Address of Next Hop:

       This field contains the IPv4 Network Address of the next router
       on the path to the destination prefix, (reasonably) assuming that
       such routers can at least be addressed according to the IPv4
       formalism.

   -  Flags, Identifier, Length and Prefix fields:

       These four fields actually compose the NLRI field of the QOS_NLRI
       attribute, and their respective meanings are as defined in
       section 2.2.2 of [11].

5.   Operation

   When advertising a QOS_NLRI attribute to an external peer, a router
   may use one of its own interface addresses in the next hop component
   of the attribute, given the external peer to which one or several
   route(s) is (are) being advertised shares a common subnet with the
   next hop address.  This is known as a "first party" next hop
   information.

   A BGP speaker can advertise to an external peer an interface of any
   internal peer router in the next hop component, provided the external
   peer to which the route is being advertised shares a common subnet
   with the next hop address.  This is known as a "third party" next hop
   information.

   A BGP speaker that sends an UPDATE message with the QOS_NLRI
   attribute has the ability to advertise multiple QoS routes, since the
   Identifier field of the attribute is part of the NLRI description. In
   particular, the same prefix can be advertised more than once without
   subsequent advertisements that would replace previous announcements.

   Since the resolution of the NEXT_HOP address that is always conveyed
   in a BGP UPDATE message is left to the responsibility of the IGP that
   has been activated within the domain, the best path according to the
   BGP route selection process depicted in [3] SHOULD also be
   advertised. As long as the routers on the path towards the address
   depicted in the NEXT_HOP attribute of the message have the additional
   paths depicted in the QOS_NLRI attribute, the propagation of QoS
   routes within a domain where all the routers are QOS_NLRI aware
   should not yield inconsistent routing.

   A BGP UPDATE message that carries the QOS_NLRI MUST also carry the
   ORIGIN and the AS_PATH attributes (both in eBGP and in iBGP
   exchanges). Moreover, in iBGP exchanges such a message MUST also

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   carry the LOCAL_PREF attribute. If such a message is received from an
   external peer, the local system shall check whether the leftmost AS
   in the AS_PATH attribute is equal to the autonomous system number of
   the peer than sent the message. If that is not the case, the local
   system shall send the NOTIFICATION message with Error Code UPDATE
   Message Error, and the Error Sub-code set to Malformed AS_PATH.

   Finally, an UPDATE message that carries no NLRI, other than the one
   encoded in the QOS_NLRI attribute, should not carry the NEXT_HOP
   attribute. If such a message contains the NEXT_HOP attribute, the BGP
   speaker that receives the message should ignore this attribute.

6.   Use of Capabilities Advertisement with BGP-4

   A BGP speaker that uses the QOS_NLRI attribute SHOULD use the
   Capabilities Advertisement procedures, as defined in [12], so that it
   might be able to determine if it can use such an attribute with a
   particular peer.

   The fields in the Capabilities Optional Parameter are defined as
   follows:

   -  The Capability Code field is set to N (127 < N < 256, when
       considering the "Private Use" range, as specified in [13]), while
       the Capability Length field is set to "1".

   -  The Capability Value field is a one-octet field, which contains
       the Type Code of the QOS_NLRI attribute, as defined in the
       introduction of section 5 of the present draft.

   In addition, the multiple path advertisement capability MUST be
   supported, as defined in section 2.1 of [4].


7.   Simulation Results

7.1.     A Phased Approach

   The simulation work basically aims at qualifying the scalability of
   the usage of the QOS_NLRI attribute for propagating QoS-related
   information across domains.

   This effort also focused on the impact on the stability of the BGP
   routes, by defining a set of basic engineering rules for the
   introduction of additional QoS information, as well as design
   considerations for the computation and the selection of "QoS routes".

   This ongoing development effort is organized into a step-by-step
   approach, which consists in the following phases:

     1. Model an IP network composed of several autonomous systems.
        Since this simulation effort is primarily focused on the

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        qualification of the scalability related to the use of the
        QOS_NLRI attribute for exchanging QoS-related information
        between domains, it has been decided that the internal
        architecture of such domains should be kept very simple, i.e.
        without any specific IGP interaction,

     2. Within this IP network, there are BGP peers that are QOS_NLRI
        aware, i.e. they have the ability to process the information
        conveyed in the attribute, while the other routers are not: the
        latter do not recognize the QOS_NLRI attribute by definition,
        and they will forward the information to other peers, by setting
        the Partial bit in the attribute, meaning that the information
        conveyed in the message is incomplete. This approach contributes
        to the qualification of a progressive deployment of QOS_NLRI-
        aware BGP peers,

     3. As far as QOS_NLRI aware BGP peers are concerned, they will
        process the information contained in the QOS_NLRI attribute to
        possibly influence the route decision process, thus yielding the
        selection (and the announcement) of distinct routes towards a
        same destination prefix, depending on the QoS-related
        information conveyed in the QOS_NLRI attribute,

     4. Modify the BGP route decision process: at this stage of the
        simulation, the modified decision process relies upon the one-
        way delay information (which corresponds to the QoS Information
        Code field of the attribute valued at "2"), and it also takes
        into account the value of the Partial bit of the attribute.

   Once the creation of these components of the IP network has been
   completed (together with the modification of the BGP route selection
   process), the behavior of a QOS_NLRI-capable BGP peer is as follows.

   Upon receipt of a BGP UPDATE message that contains the QOS_NLRI
   attribute, the router will first check if the corresponding route is
   already stored in its local RIB, according to the value of the one-
   way delay information contained in both QoS Information Code and Sub-
   code fields of the attribute.

   If not, the BGP peer will install the route in its local RIB.
   Otherwise (i.e. an equivalent route already exists in its database),
   the BGP peer will select the best of both routes according to the
   following criteria:

   - If both routes are said to be either incomplete (Partial bit has
      been set) or complete (Partial bit is unset), the route with the
      lowest delay will be selected,

   - Otherwise, a route with the Partial bit unset is always preferred
      over any other route, even if this route reflects a higher transit
      delay.


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   If ever both Partial bit and transit delay information are not
   sufficient to make a decision, the standard BGP decision process
   (according to the breaking ties mechanism depicted in [3]) is
   performed.

7.2.     A Case Study

   REMINDER: a PDF version of this document (which includes the figures
   mentioned in this section) can be accessed at http://www.mescal.org.

   As stated in the previous section 7.1, the current status of the
   simulation work basically relies upon the one-way transit delay
   information only, as well as the complete/incomplete indication of
   the Partial bit conveyed in the QOS_NLRI attribute.

   The following figures depict the actual processing of the QoS-related
   information conveyed in the QOS_NLRI attribute, depending on whether
   the peer is QOS_NRLI-aware or not.

                          [Fig. 1: A Case Study.]

   Figure 1 depicts the IP network that has been modelled, while figure
   2 depicts the propagation of a BGP UPDATE message that contains the
   QOS_NLRI attribute, in the case where the contents of the attribute
   are changed, because of complete/incomplete conditions depicted by
   the Partial bit of the QOS_NLRI attribute.

       [Fig. 2: Propagation of One-way Delay Information via BGP4.]

   Router S in figure 2 is a QOS_NRLI-capable speaker. It takes 20
   milliseconds for node S to reach network 192.0.20.0: this information
   will be conveyed in a QOS_NLRI attribute that will be sent by node S
   in a BGP UPDATE message with the Partial bit of the QOS_NLRI
   attribute unset.

   Router A is another QOS_NLRI BGP peer, and it takes 3 milliseconds
   for A to reach router S. Node A will update the QoS-related
   information of a QOS_NLRI attribute, indicating that, to reach
   network 192.0.20.0, it takes 23 milliseconds. Router A will install
   this new route in its database, and will propagate the corresponding
   UPDATE message to its peers.

   On the other hand, router B is not capable of processing the
   information conveyed in the QOS_NLRI attribute, and it will therefore
   set the Partial bit of the QOS_NLRI attribute in the corresponding
   UPDATE message, leaving the one-way delay information detailed in
   both QoS Information Code and Sub-code unchanged.

   Upon receipt of the UPDATE message sent by router A, router E will
   update the one-way delay information since it is a QOS_NRLI-capable
   peer. Finally, router D receives the UPDATE message, and selects a


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   route  with  a  40  milliseconds  one-way  delay  to  reach  network
   192.0.20.0, as depicted in figure 3.

              [Fig. 3: Selecting QoS Routes Across Domains.]

   This simulation result shows that the selection of a delay-inferred
   route over a BGP route may not yield an optimal decision. In the
   above example, the 40 ms-route goes through routers D-E-A-S, while a
   "truly optimal" BGP route would be through routers D-E-F-A-S, hence a
   38 ms-route. This is because of a BGP4 rule that does not allow
   router F to send an UPDATE message towards router E, because router F
   received the UPDATE message from router A thanks to the iBGP
   connection it has established with A.

7.3.     Additional Results

   The following table reflects the results obtained from a simulation
   network composed of 9 autonomous systems and 20 BGP peers. The
   numbers contained in the columns reflect the percentage of serviced
   requirements, where the requirements are expressed in terms of delay.

   Three parameters have been taken into account:

   - The percentage of BGP peers that have the ability to process the
     information conveyed in the QOS_NLRI attribute (denoted as "x% Q-
     BGP" in the following table),

   - The transit delays "observed" (and artificially simulated) on each
     transmission link: the higher the delays, the lower the percentage
     of serviced QoS requirements,

   - The QoS requirements themselves, expressed in terms of delay: as
     such, the strongest requirements (i.e. the lowest delays) have less
     chance to be satisfied.

            +-------------------------------------------+
            | Delay | 0% Q-BGP | 50% Q-BGP | 100% Q-BGP |
            +-------------------------------------------+
            |  3    |    11    |    8,3    |    11      |
            +-------------------------------------------+
            |  5    |    30,5  |    30,5   |    36,1    |
            +-------------------------------------------+
            |  6    |    40    |    47,2   |    55,5    |
            +-------------------------------------------+
            |  7    |    47    |    59,7   |    72,2    |
            +-------------------------------------------+
            |  8    |    62,5  |    79     |    91,6    |
            +-------------------------------------------+
            |  9    |    63    |    84,7   |    97,2    |
            +-------------------------------------------+
            |  10   |    70,8  |    90,2   |    98,6    |
            +-------------------------------------------+

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            |  11   |    76,3  |    93     |    98,6    |
            +-------------------------------------------+
            |  12   |    86,1  |    97,2   |    100     |
            +-------------------------------------------+
            |  13   |    88,8  |    98,6   |    100     |
            +-------------------------------------------+
            |  14   |    94,4  |    100    |    100     |
            +-------------------------------------------+
            |  15   |    94,4  |    100    |    100     |
            +-------------------------------------------+
            |  16   |    94,4  |    100    |    100     |
            +-------------------------------------------+
            |  17   |    97,2  |    100    |    100     |
            +-------------------------------------------+
            |  18   |    98,6  |    100    |    100     |
            +-------------------------------------------+
            |  19   |    98,6  |    100    |    100     |
            +-------------------------------------------+
            |  20   |    98,6  |    100    |    100     |
            +-------------------------------------------+
            |  21   |    98,6  |    100    |    100     |
            +-------------------------------------------+
            |  22   |    100   |    100    |    100     |
            +-------------------------------------------+

   This table clearly demonstrates the technical feasibility of the
   approach, and how the use of the QOS_NLRI attribute can improve the
   percentage of serviced QoS requirements.

7.4.     Next Steps

   This simulation effort is currently pursued in order to better
   qualify the interest of using the BGP4 protocol to convey QoS-related
   information between domains, from a scalability perspective, i.e. the
   growth of BGP traffic vs. the stability of the network.

   The stability of the IP network is probably one of the most important
   aspects, since QoS-related information is subject to very dynamic
   changes, thus yielding non-negligible risks of flapping.

8.   IANA Considerations

   Section 4 of this draft documents an optional transitive BGP-4
   attribute named "QOS_NLRI" whose type value will be assigned by IANA.
   Section 5 of this draft also documents a Capability Code whose value
   should be assigned by IANA as well.

9.   Security Considerations

   This additional BGP-4 attribute specification does not change the
   underlying security issues inherent in the existing BGP-4 protocol
   specification [14].

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10.    References

   [1]  Bradner, S., "The Internet Standards Process -- Revision 3", BCP
      9, RFC 2026, October 1996.
   [2]  Bradner, S., "Key words for use in RFCs to Indicate Requirement
      Levels", BCP 14, RFC 2119, March 1997.
   [3]  Rekhter, Y., Li T., "A Border Gateway Protocol 4 (BGP-4)", RFC
      1771, March 1995.
   [4]  Almes, G., Kalidindi, S., "A One-Way-Delay Metric for IPPM", RFC
      2679, September 1999.
   [5]  Demichelis, C., Chimento, P., "IP Packet Delay Variation Metric
      for IP Performance Metrics (IPPM)", RFC 3393, November 2002.
   [6]  Nichols, K., Blake, S., Baker, F., Black, D., "Definition of the
      Differentiated Services Field (DS Field) in the IPv4 and IPv6
      Headers", RFC 2474, December 1998.
   [7]  Traina, P., McPherson, D., Scudder, J., "Autonomous System
      Confederations for BGP", RFC 3065, February 2001.
   [8]  Jacquenet, C., "A COPS Client-Type for Traffic Engineering",
      draft-jacquenet-cops-te-00.txt, Work in Progress, February 2004.
   [9]  Apostolopoulos, G. et al, "QoS Routing Mechanisms and OSPF
      Extensions", RFC 2676, August 1999.
   [10] Reynolds, J., Postel, J., "ASSIGNED NUMBERS", RFC 1700, October
      1994.
   [11] Walton, D., et al., "Advertisement of Multiple Paths in BGP",
      draft-walton-bgp-add-paths-01.txt, Work in Progress, November
      2002.
   [12] Chandra, R., Scudder, J., "Capabilities Advertisement with BGP-
      4", RFC 3392, November 2002.
   [13] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA
      Considerations Section in RFCs", RFC 2434, October 1998.
   [14] Heffernan, A., "Protection of BGP sessions via the TCP MD5
      Signature Option", RFC 2385, August 1998.

11.    Acknowledgments

   Part of this work is funded by the European Commission, within the
   context of the MESCAL (Management of End-to-End Quality of Service
   Across the Internet At Large, http://www.mescal.org) project, which
   is itself part of the IST (Information Society Technologies) research
   program.

   The author would also like to thank all the partners of the MESCAL
   project for the fruitful discussions that have been conducted within
   the context of the traffic engineering specification effort of the
   project, as well as O. Bonaventure and B. Carpenter for their
   valuable input.




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12.    Authors' Addresses

   Geoffrey Cristallo
   Alcatel
   Francis Wellesplein, 1
   2018 Antwerp
   Belgium
   Phone: +32 (0)3 240 7890
   E-Mail: geoffrey.cristallo@alcatel.be

   Christian Jacquenet
   France Telecom
   3, avenue François Château
   CS 36901
   35069 Rennes Cedex
   France
   Phone: +33 2 99 87 63 31
   Email: christian.jacquenet@francetelecom.com

13.    Full Copyright Statement

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

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   provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works. However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
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   developing Internet standards in which case the procedures for
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   followed, or as required to translate it into languages other than
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   The limited permissions granted above are perpetual and will not be
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