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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group G. Cristallo 3 Internet Draft Alcatel 4 Document: draft-jacquenet-bgp-qos-00.txt C. Jacquenet 5 Category: Experimental France Telecom 6 Expires August 2004 February 2004 8 The BGP QOS_NLRI Attribute 9 11 Status of this Memo 13 This document is an Internet-Draft and is in full conformance with 14 all provisions of Section 10 of RFC 2026 [1]. 16 Internet-Drafts are working documents of the Internet Engineering 17 Task Force (IETF), its areas, and its working groups. Note that other 18 groups may also distribute working documents as Internet-Drafts. 19 Internet-Drafts are draft documents valid for a maximum of six months 20 and may be updated, replaced, or obsoleted by other documents at any 21 time. It is inappropriate to use Internet Drafts as reference 22 material or to cite them other than as "work in progress". 24 The list of current Internet-Drafts can be accessed at 25 http://www.ietf.org/ietf/1id-abstracts.txt. 27 The list of Internet-Draft Shadow Directories can be accessed at 28 http://www.ietf.org/shadow.html. 30 NOTE: a PDF version of this document (which includes the figures 31 mentioned in section 7) can be accessed at http://www.mescal.org. 33 Abstract 35 This draft specifies an additional BGP4 (Border Gateway Protocol, 36 version 4) attribute, named the "QOS_NLRI" attribute, which aims at 37 propagating QoS (Quality of Service)-related information associated 38 to the NLRI (Network Layer Reachability Information) information 39 conveyed in a BGP UPDATE message. 41 Table of Contents 43 1. Conventions Used in this Document..........................2 44 2. Introduction...............................................2 45 3. Basic Requirements.........................................3 46 4. The QOS_NLRI Attribute (Type Code tbd*)....................3 47 5. Operation..................................................7 48 6. Use of Capabilities Advertisement with BGP-4...............8 49 7. Simulation Results.........................................8 50 7.1. A Phased Approach..........................................8 51 7.2. A Case Study..............................................10 52 7.3. Additional Results........................................11 53 7.4. Next Steps................................................12 54 8. IANA Considerations.......................................12 55 9. Security Considerations...................................12 56 10. References................................................13 57 11. Acknowledgments...........................................13 58 12. Authors' Addresses........................................14 59 13. Full Copyright Statement..................................14 61 1. Conventions Used in this Document 63 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 64 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 65 document are to be interpreted as described in RFC 2119 [2]. 67 2. Introduction 69 Providing end-to-end quality of service is one of the most important 70 challenges of the Internet, not only because of the massive 71 development of value-added IP service offerings, but also because of 72 the various QoS policies that are currently enforced within an 73 autonomous system, and which may well differ from one AS (Autonomous 74 System) to another. 76 For the last decade, value-added IP service offerings have been 77 deployed over the Internet, thus yielding a dramatic development of 78 the specification effort, as far as quality of service in IP networks 79 is concerned. Nevertheless, providing end-to-end quality of service 80 across administrative domains still remains an issue, mainly because: 82 - QoS policies may dramatically differ from one service provider to 83 another, 85 - The enforcement of a specific QoS policy may also differ from one 86 domain to another, although the definition of a set of common 87 quality of service indicators may be shared between the service 88 providers. 90 Activate the BGP4 protocol ([3]) for exchanging reachability 91 information between autonomous systems has been a must for many 92 years. Therefore, disseminating QoS information coupled with 93 reachability information in a given BGP UPDATE message appears to be 94 helpful in enforcing an end-to-end QoS policy. 96 This draft aims at specifying a new BGP4 attribute, the QOS_NLRI 97 attribute, which will convey QoS-related information associated to 98 the routes described in the corresponding NLRI field of the 99 attribute. 101 This document is organized according to the following sections: 103 - Section 3 describes the basic requirements that motivate the 104 approach, 106 - Section 4 describes the attribute, 108 - Section 5 elaborates on the mode of operation, 110 - Section 6 elaborates on the use of the capabilities advertisement 111 feature of the BGP4 protocol, 113 - Section 7 depicts the results of a simulation work, 115 - Finally, sections 8 and 9 introduce IANA and some security 116 considerations, respectively. 118 3. Basic Requirements 120 The choice of using the BGP4 protocol for exchanging QoS information 121 between domains is not only motivated by the fact BGP is currently 122 the only inter-domain (routing) protocol activated in the Internet, 123 but also because the manipulation of attributes is a powerful means 124 for service providers to disseminate QoS information with the desired 125 level of precision. 127 The approach presented in this draft has identified the following 128 requirements: 130 - Keep the approach scalable. The scalability of the approach can be 131 defined in many ways that include the convergence time taken by the 132 BGP peers to reach a consistent view of the network connectivity, 133 the number of route entries that will have to be maintained by a 134 BGP peer, the dynamics of the route announcement mechanism (e.g., 135 how frequently and under which conditions should an UPDATE message 136 containing QoS information be sent?), etc. 138 - Keep the BGP4 protocol operation unchanged. The introduction of a 139 new attribute should not affect the way the protocol operates, but 140 the information contained in this attribute may very well influence 141 the BGP route selection process. 143 - Allow for a smooth migration. The use of a specific BGP attribute 144 to convey QoS information should not constrain network operators to 145 migrate the whole installed base at once, but rather help them in 146 gradually deploying the QoS information processing capability. 148 4. The QOS_NLRI Attribute (Type Code tbd*) 150 (*): "tbd" is subject to the IANA considerations section of this 151 draft. 153 The QOS_NLRI attribute is an optional transitive attribute that can 154 be used: 156 1. To advertise a QoS route to a peer. A QoS route is a route that 157 meets one or a set of QoS requirement(s) to reach a given (set of) 158 destination prefixes. Such QoS requirements can be expressed in 159 terms of minimum one-way delay ([4]) to reach a destination, the 160 experienced delay variation for IP datagrams that are destined to 161 a given destination prefix ([5]), the loss rate experienced along 162 the path to reach a destination, and/or the identification of the 163 traffic that is expected to use this specific route 164 (identification means for such traffic include DSCP (DiffServ Code 165 Point, [6]) marking). These QoS requirements can be used as an 166 input for the BGP route calculation process, 168 2. To provide QoS-related information along with the NLRI information 169 in a single BGP UPDATE message. It is assumed that this 170 information will be related to the route (or set of routes) 171 described in the NLRI field of the attribute. 173 From a service provider's perspective, the choice of defining the 174 QOS_NLRI attribute as an optional transitive attribute is motivated 175 by the fact that this kind of attribute allows for gradual deployment 176 of the dissemination of QoS-related information by BGP4: not all the 177 BGP peers are supposed to be updated accordingly, while partial 178 deployment of such QoS extensions can already provide an added value, 179 e.g. in the case where a service provider manages multiple domains, 180 and/or has deployed a BGP confederation ([7]). 182 This draft makes no specific assumption about the means to actually 183 value this attribute, since this is mostly a matter of 184 implementation, but the reader is suggested to have a look on 185 document [8], as an example of a means to feed the BGP peer with the 186 appropriate information. The QOS_NLRI attribute is encoded as 187 follows: 189 +---------------------------------------------------------+ 190 | QoS Information Code (1 octet) | 191 +---------------------------------------------------------+ 192 | QoS Information Sub-code (1 octet) | 193 +---------------------------------------------------------+ 194 | QoS Information Value (2 octets) | 195 +---------------------------------------------------------+ 196 | QoS Information Origin (1 octet) | 197 +---------------------------------------------------------+ 198 | Address Family Identifier (2 octets) | 199 +---------------------------------------------------------+ 200 | Subsequent Address Family Identifier (1 octet) | 201 +---------------------------------------------------------+ 202 | Network Address of Next Hop (4 octets) | 203 +---------------------------------------------------------+ 204 | Flags (1 octet) | 205 +---------------------------------------------------------+ 206 | Identifier (2 octets) | 207 +---------------------------------------------------------+ 208 | Length (1 octet) | 209 +---------------------------------------------------------+ 210 | Prefix (variable) | 211 +---------------------------------------------------------+ 213 The use and meaning of the fields of the QOS_NLRI attribute are 214 defined as follows: 216 - QoS Information Code: 218 This field carries the type of the QOS information. The following 219 types have been identified so far: 221 (0) Reserved 222 (1) Packet rate, i.e. the number of IP datagrams that can be 223 transmitted (or have been lost) per unit of time, this number 224 being characterized by the elaboration provided in the QoS 225 Information Sub-code (see below) 226 (2) One-way delay metric 227 (3) Inter-packet delay variation 228 (4) PHB Identifier 230 - QoS Information Sub-Code: 232 This field carries the sub-type of the QoS information. The 233 following sub-types have been identified so far: 235 (0) None (i.e. no sub-type, or sub-type unavailable, or unknown sub- 236 type) 237 (1) Reserved rate 238 (2) Available rate 239 (3) Loss rate 240 (4) Minimum one-way delay 241 (5) Maximum one-way delay 242 (6) Average one-way delay 244 The instantiation of this sub-code field MUST be compatible with the 245 value conveyed in the QoS Information code field, as stated in the 246 following table (the rows represent the QoS Information Code possible 247 values, the columns represent the QoS Information Sub-code values 248 identified so far, while the "X" sign indicates incompatibility). 250 +---------------------------------------+ 251 | | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 252 +---------------------------------------+ 253 | 0 | | | | | | | | 254 +---------------------------------------+ 255 | 1 | | | | | X | X | X | 256 +---------------------------------------+ 257 | 2 | | X | X | X | | | | 258 +---------------------------------------+ 259 | 3 | | X | X | X | X | X | X | 260 +---------------------------------------+ 261 | 4 | | X | X | X | X | X | X | 262 +---------------------------------------+ 264 - QoS Information Value: 266 This field indicates the value of the QoS information. The 267 corresponding units obviously depend on the instantiation of the 268 QoS Information Code. Namely, if: 270 (a) QoS Information Code field is "0", no unit specified, 271 (b) QoS Information Code field is "1", unit is kilobits per second 272 (kbps), and the rate encoding rule is composed of a 3-bit 273 exponent (with an assumed base of 8) followed by a 13-bit 274 mantissa, as depicted in the figure below: 276 0 8 16 277 | | | 278 ----------------- 279 |Exp| Mantissa | 280 ----------------- 282 This encoding scheme advertises a numeric value that is (2^16 -1 283 - exponential encoding of the considered rate), as depicted in 284 [9]. 285 (c) QoS Information Code field is "2", unit is milliseconds, 286 (d) QoS Information Code field is "3", unit is milliseconds, 287 (e) QoS Information Code field is "4", no unit specified. 289 - QoS Information Origin: 291 This field provides indication on the origin of the path 292 information, as defined in section 4.3.of [3]. 294 - Address Family Identifier (AFI): 296 This field carries the identity of the Network Layer protocol 297 associated with the Network Address that follows. Currently 298 defined values for this field are specified in [10] (see the 299 Address Family Numbers section of this reference document). 301 - Subsequent Address Family Identifier (SAFI): 303 This field provides additional information about the type of the 304 prefix carried in the QOS_NLRI attribute. 306 - Network Address of Next Hop: 308 This field contains the IPv4 Network Address of the next router 309 on the path to the destination prefix, (reasonably) assuming that 310 such routers can at least be addressed according to the IPv4 311 formalism. 313 - Flags, Identifier, Length and Prefix fields: 315 These four fields actually compose the NLRI field of the QOS_NLRI 316 attribute, and their respective meanings are as defined in 317 section 2.2.2 of [11]. 319 5. Operation 321 When advertising a QOS_NLRI attribute to an external peer, a router 322 may use one of its own interface addresses in the next hop component 323 of the attribute, given the external peer to which one or several 324 route(s) is (are) being advertised shares a common subnet with the 325 next hop address. This is known as a "first party" next hop 326 information. 328 A BGP speaker can advertise to an external peer an interface of any 329 internal peer router in the next hop component, provided the external 330 peer to which the route is being advertised shares a common subnet 331 with the next hop address. This is known as a "third party" next hop 332 information. 334 A BGP speaker that sends an UPDATE message with the QOS_NLRI 335 attribute has the ability to advertise multiple QoS routes, since the 336 Identifier field of the attribute is part of the NLRI description. In 337 particular, the same prefix can be advertised more than once without 338 subsequent advertisements that would replace previous announcements. 340 Since the resolution of the NEXT_HOP address that is always conveyed 341 in a BGP UPDATE message is left to the responsibility of the IGP that 342 has been activated within the domain, the best path according to the 343 BGP route selection process depicted in [3] SHOULD also be 344 advertised. As long as the routers on the path towards the address 345 depicted in the NEXT_HOP attribute of the message have the additional 346 paths depicted in the QOS_NLRI attribute, the propagation of QoS 347 routes within a domain where all the routers are QOS_NLRI aware 348 should not yield inconsistent routing. 350 A BGP UPDATE message that carries the QOS_NLRI MUST also carry the 351 ORIGIN and the AS_PATH attributes (both in eBGP and in iBGP 352 exchanges). Moreover, in iBGP exchanges such a message MUST also 353 carry the LOCAL_PREF attribute. If such a message is received from an 354 external peer, the local system shall check whether the leftmost AS 355 in the AS_PATH attribute is equal to the autonomous system number of 356 the peer than sent the message. If that is not the case, the local 357 system shall send the NOTIFICATION message with Error Code UPDATE 358 Message Error, and the Error Sub-code set to Malformed AS_PATH. 360 Finally, an UPDATE message that carries no NLRI, other than the one 361 encoded in the QOS_NLRI attribute, should not carry the NEXT_HOP 362 attribute. If such a message contains the NEXT_HOP attribute, the BGP 363 speaker that receives the message should ignore this attribute. 365 6. Use of Capabilities Advertisement with BGP-4 367 A BGP speaker that uses the QOS_NLRI attribute SHOULD use the 368 Capabilities Advertisement procedures, as defined in [12], so that it 369 might be able to determine if it can use such an attribute with a 370 particular peer. 372 The fields in the Capabilities Optional Parameter are defined as 373 follows: 375 - The Capability Code field is set to N (127 < N < 256, when 376 considering the "Private Use" range, as specified in [13]), while 377 the Capability Length field is set to "1". 379 - The Capability Value field is a one-octet field, which contains 380 the Type Code of the QOS_NLRI attribute, as defined in the 381 introduction of section 5 of the present draft. 383 In addition, the multiple path advertisement capability MUST be 384 supported, as defined in section 2.1 of [4]. 386 7. Simulation Results 388 7.1. A Phased Approach 390 The simulation work basically aims at qualifying the scalability of 391 the usage of the QOS_NLRI attribute for propagating QoS-related 392 information across domains. 394 This effort also focused on the impact on the stability of the BGP 395 routes, by defining a set of basic engineering rules for the 396 introduction of additional QoS information, as well as design 397 considerations for the computation and the selection of "QoS routes". 399 This ongoing development effort is organized into a step-by-step 400 approach, which consists in the following phases: 402 1. Model an IP network composed of several autonomous systems. 403 Since this simulation effort is primarily focused on the 404 qualification of the scalability related to the use of the 405 QOS_NLRI attribute for exchanging QoS-related information 406 between domains, it has been decided that the internal 407 architecture of such domains should be kept very simple, i.e. 408 without any specific IGP interaction, 410 2. Within this IP network, there are BGP peers that are QOS_NLRI 411 aware, i.e. they have the ability to process the information 412 conveyed in the attribute, while the other routers are not: the 413 latter do not recognize the QOS_NLRI attribute by definition, 414 and they will forward the information to other peers, by setting 415 the Partial bit in the attribute, meaning that the information 416 conveyed in the message is incomplete. This approach contributes 417 to the qualification of a progressive deployment of QOS_NLRI- 418 aware BGP peers, 420 3. As far as QOS_NLRI aware BGP peers are concerned, they will 421 process the information contained in the QOS_NLRI attribute to 422 possibly influence the route decision process, thus yielding the 423 selection (and the announcement) of distinct routes towards a 424 same destination prefix, depending on the QoS-related 425 information conveyed in the QOS_NLRI attribute, 427 4. Modify the BGP route decision process: at this stage of the 428 simulation, the modified decision process relies upon the one- 429 way delay information (which corresponds to the QoS Information 430 Code field of the attribute valued at "2"), and it also takes 431 into account the value of the Partial bit of the attribute. 433 Once the creation of these components of the IP network has been 434 completed (together with the modification of the BGP route selection 435 process), the behavior of a QOS_NLRI-capable BGP peer is as follows. 437 Upon receipt of a BGP UPDATE message that contains the QOS_NLRI 438 attribute, the router will first check if the corresponding route is 439 already stored in its local RIB, according to the value of the one- 440 way delay information contained in both QoS Information Code and Sub- 441 code fields of the attribute. 443 If not, the BGP peer will install the route in its local RIB. 444 Otherwise (i.e. an equivalent route already exists in its database), 445 the BGP peer will select the best of both routes according to the 446 following criteria: 448 - If both routes are said to be either incomplete (Partial bit has 449 been set) or complete (Partial bit is unset), the route with the 450 lowest delay will be selected, 452 - Otherwise, a route with the Partial bit unset is always preferred 453 over any other route, even if this route reflects a higher transit 454 delay. 456 If ever both Partial bit and transit delay information are not 457 sufficient to make a decision, the standard BGP decision process 458 (according to the breaking ties mechanism depicted in [3]) is 459 performed. 461 7.2. A Case Study 463 REMINDER: a PDF version of this document (which includes the figures 464 mentioned in this section) can be accessed at http://www.mescal.org. 466 As stated in the previous section 7.1, the current status of the 467 simulation work basically relies upon the one-way transit delay 468 information only, as well as the complete/incomplete indication of 469 the Partial bit conveyed in the QOS_NLRI attribute. 471 The following figures depict the actual processing of the QoS-related 472 information conveyed in the QOS_NLRI attribute, depending on whether 473 the peer is QOS_NRLI-aware or not. 475 [Fig. 1: A Case Study.] 477 Figure 1 depicts the IP network that has been modelled, while figure 478 2 depicts the propagation of a BGP UPDATE message that contains the 479 QOS_NLRI attribute, in the case where the contents of the attribute 480 are changed, because of complete/incomplete conditions depicted by 481 the Partial bit of the QOS_NLRI attribute. 483 [Fig. 2: Propagation of One-way Delay Information via BGP4.] 485 Router S in figure 2 is a QOS_NRLI-capable speaker. It takes 20 486 milliseconds for node S to reach network 192.0.20.0: this information 487 will be conveyed in a QOS_NLRI attribute that will be sent by node S 488 in a BGP UPDATE message with the Partial bit of the QOS_NLRI 489 attribute unset. 491 Router A is another QOS_NLRI BGP peer, and it takes 3 milliseconds 492 for A to reach router S. Node A will update the QoS-related 493 information of a QOS_NLRI attribute, indicating that, to reach 494 network 192.0.20.0, it takes 23 milliseconds. Router A will install 495 this new route in its database, and will propagate the corresponding 496 UPDATE message to its peers. 498 On the other hand, router B is not capable of processing the 499 information conveyed in the QOS_NLRI attribute, and it will therefore 500 set the Partial bit of the QOS_NLRI attribute in the corresponding 501 UPDATE message, leaving the one-way delay information detailed in 502 both QoS Information Code and Sub-code unchanged. 504 Upon receipt of the UPDATE message sent by router A, router E will 505 update the one-way delay information since it is a QOS_NRLI-capable 506 peer. Finally, router D receives the UPDATE message, and selects a 507 route with a 40 milliseconds one-way delay to reach network 508 192.0.20.0, as depicted in figure 3. 510 [Fig. 3: Selecting QoS Routes Across Domains.] 512 This simulation result shows that the selection of a delay-inferred 513 route over a BGP route may not yield an optimal decision. In the 514 above example, the 40 ms-route goes through routers D-E-A-S, while a 515 "truly optimal" BGP route would be through routers D-E-F-A-S, hence a 516 38 ms-route. This is because of a BGP4 rule that does not allow 517 router F to send an UPDATE message towards router E, because router F 518 received the UPDATE message from router A thanks to the iBGP 519 connection it has established with A. 521 7.3. Additional Results 523 The following table reflects the results obtained from a simulation 524 network composed of 9 autonomous systems and 20 BGP peers. The 525 numbers contained in the columns reflect the percentage of serviced 526 requirements, where the requirements are expressed in terms of delay. 528 Three parameters have been taken into account: 530 - The percentage of BGP peers that have the ability to process the 531 information conveyed in the QOS_NLRI attribute (denoted as "x% Q- 532 BGP" in the following table), 534 - The transit delays "observed" (and artificially simulated) on each 535 transmission link: the higher the delays, the lower the percentage 536 of serviced QoS requirements, 538 - The QoS requirements themselves, expressed in terms of delay: as 539 such, the strongest requirements (i.e. the lowest delays) have less 540 chance to be satisfied. 542 +-------------------------------------------+ 543 | Delay | 0% Q-BGP | 50% Q-BGP | 100% Q-BGP | 544 +-------------------------------------------+ 545 | 3 | 11 | 8,3 | 11 | 546 +-------------------------------------------+ 547 | 5 | 30,5 | 30,5 | 36,1 | 548 +-------------------------------------------+ 549 | 6 | 40 | 47,2 | 55,5 | 550 +-------------------------------------------+ 551 | 7 | 47 | 59,7 | 72,2 | 552 +-------------------------------------------+ 553 | 8 | 62,5 | 79 | 91,6 | 554 +-------------------------------------------+ 555 | 9 | 63 | 84,7 | 97,2 | 556 +-------------------------------------------+ 557 | 10 | 70,8 | 90,2 | 98,6 | 558 +-------------------------------------------+ 559 | 11 | 76,3 | 93 | 98,6 | 560 +-------------------------------------------+ 561 | 12 | 86,1 | 97,2 | 100 | 562 +-------------------------------------------+ 563 | 13 | 88,8 | 98,6 | 100 | 564 +-------------------------------------------+ 565 | 14 | 94,4 | 100 | 100 | 566 +-------------------------------------------+ 567 | 15 | 94,4 | 100 | 100 | 568 +-------------------------------------------+ 569 | 16 | 94,4 | 100 | 100 | 570 +-------------------------------------------+ 571 | 17 | 97,2 | 100 | 100 | 572 +-------------------------------------------+ 573 | 18 | 98,6 | 100 | 100 | 574 +-------------------------------------------+ 575 | 19 | 98,6 | 100 | 100 | 576 +-------------------------------------------+ 577 | 20 | 98,6 | 100 | 100 | 578 +-------------------------------------------+ 579 | 21 | 98,6 | 100 | 100 | 580 +-------------------------------------------+ 581 | 22 | 100 | 100 | 100 | 582 +-------------------------------------------+ 584 This table clearly demonstrates the technical feasibility of the 585 approach, and how the use of the QOS_NLRI attribute can improve the 586 percentage of serviced QoS requirements. 588 7.4. Next Steps 590 This simulation effort is currently pursued in order to better 591 qualify the interest of using the BGP4 protocol to convey QoS-related 592 information between domains, from a scalability perspective, i.e. the 593 growth of BGP traffic vs. the stability of the network. 595 The stability of the IP network is probably one of the most important 596 aspects, since QoS-related information is subject to very dynamic 597 changes, thus yielding non-negligible risks of flapping. 599 8. IANA Considerations 601 Section 4 of this draft documents an optional transitive BGP-4 602 attribute named "QOS_NLRI" whose type value will be assigned by IANA. 603 Section 5 of this draft also documents a Capability Code whose value 604 should be assigned by IANA as well. 606 9. Security Considerations 608 This additional BGP-4 attribute specification does not change the 609 underlying security issues inherent in the existing BGP-4 protocol 610 specification [14]. 612 10. References 614 [1] Bradner, S., "The Internet Standards Process -- Revision 3", BCP 615 9, RFC 2026, October 1996. 616 [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement 617 Levels", BCP 14, RFC 2119, March 1997. 618 [3] Rekhter, Y., Li T., "A Border Gateway Protocol 4 (BGP-4)", RFC 619 1771, March 1995. 620 [4] Almes, G., Kalidindi, S., "A One-Way-Delay Metric for IPPM", RFC 621 2679, September 1999. 622 [5] Demichelis, C., Chimento, P., "IP Packet Delay Variation Metric 623 for IP Performance Metrics (IPPM)", RFC 3393, November 2002. 624 [6] Nichols, K., Blake, S., Baker, F., Black, D., "Definition of the 625 Differentiated Services Field (DS Field) in the IPv4 and IPv6 626 Headers", RFC 2474, December 1998. 627 [7] Traina, P., McPherson, D., Scudder, J., "Autonomous System 628 Confederations for BGP", RFC 3065, February 2001. 629 [8] Jacquenet, C., "A COPS Client-Type for Traffic Engineering", 630 draft-jacquenet-cops-te-00.txt, Work in Progress, February 2004. 631 [9] Apostolopoulos, G. et al, "QoS Routing Mechanisms and OSPF 632 Extensions", RFC 2676, August 1999. 633 [10] Reynolds, J., Postel, J., "ASSIGNED NUMBERS", RFC 1700, October 634 1994. 635 [11] Walton, D., et al., "Advertisement of Multiple Paths in BGP", 636 draft-walton-bgp-add-paths-01.txt, Work in Progress, November 637 2002. 638 [12] Chandra, R., Scudder, J., "Capabilities Advertisement with BGP- 639 4", RFC 3392, November 2002. 640 [13] Narten, T., Alvestrand, H., "Guidelines for Writing an IANA 641 Considerations Section in RFCs", RFC 2434, October 1998. 642 [14] Heffernan, A., "Protection of BGP sessions via the TCP MD5 643 Signature Option", RFC 2385, August 1998. 645 11. Acknowledgments 647 Part of this work is funded by the European Commission, within the 648 context of the MESCAL (Management of End-to-End Quality of Service 649 Across the Internet At Large, http://www.mescal.org) project, which 650 is itself part of the IST (Information Society Technologies) research 651 program. 653 The author would also like to thank all the partners of the MESCAL 654 project for the fruitful discussions that have been conducted within 655 the context of the traffic engineering specification effort of the 656 project, as well as O. Bonaventure and B. Carpenter for their 657 valuable input. 659 12. Authors' Addresses 661 Geoffrey Cristallo 662 Alcatel 663 Francis Wellesplein, 1 664 2018 Antwerp 665 Belgium 666 Phone: +32 (0)3 240 7890 667 E-Mail: geoffrey.cristallo@alcatel.be 669 Christian Jacquenet 670 France Telecom 671 3, avenue Fran�ois Ch�teau 672 CS 36901 673 35069 Rennes Cedex 674 France 675 Phone: +33 2 99 87 63 31 676 Email: christian.jacquenet@francetelecom.com 678 13. Full Copyright Statement 680 Copyright(C) The Internet Society (2004). All Rights Reserved. 682 This document and translations of it may be copied and furnished to 683 others, and derivative works that comment on or otherwise explain it 684 or assist its implementation may be prepared, copied, published and 685 distributed, in whole or in part, without restriction of any kind, 686 provided that the above copyright notice and this paragraph are 687 included on all such copies and derivative works. However, this 688 document itself may not be modified in any way, such as by removing 689 the copyright notice or references to the Internet Society or other 690 Internet organizations, except as needed for the purpose of 691 developing Internet standards in which case the procedures for 692 copyrights defined in the Internet Standards process must be 693 followed, or as required to translate it into languages other than 694 English. 696 The limited permissions granted above are perpetual and will not be 697 revoked by the Internet Society or its successors or assigns. 699 This document and the information contained herein is provided on an 700 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING 701 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING 702 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION 703 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF 704 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.