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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Internet Engineering Task Force P. Savola 2 Internet-Draft CSC/FUNET 3 Obsoletes: 2908,2909 (if approved) November 29, 2004 4 Expires: May 30, 2005 6 Overview of the Internet Multicast Addressing Architecture 7 draft-ietf-mboned-addrarch-00.txt 9 Status of this Memo 11 This document is an Internet-Draft and is subject to all provisions 12 of section 3 of RFC 3667. By submitting this Internet-Draft, each 13 author represents that any applicable patent or other IPR claims of 14 which he or she is aware have been or will be disclosed, and any of 15 which he or she become aware will be disclosed, in accordance with 16 RFC 3668. 18 Internet-Drafts are working documents of the Internet Engineering 19 Task Force (IETF), its areas, and its working groups. Note that 20 other groups may also distribute working documents as 21 Internet-Drafts. 23 Internet-Drafts are draft documents valid for a maximum of six months 24 and may be updated, replaced, or obsoleted by other documents at any 25 time. It is inappropriate to use Internet-Drafts as reference 26 material or to cite them other than as "work in progress." 28 The list of current Internet-Drafts can be accessed at 29 http://www.ietf.org/ietf/1id-abstracts.txt. 31 The list of Internet-Draft Shadow Directories can be accessed at 32 http://www.ietf.org/shadow.html. 34 This Internet-Draft will expire on May 30, 2005. 36 Copyright Notice 38 Copyright (C) The Internet Society (2004). 40 Abstract 42 The lack of up-to-date documentation on IP multicast address 43 allocation and assignment procedures has caused a great deal of 44 confusion. To clarify the situation, this memo describes the 45 allocation and assignment techniques and mechanisms currently (as of 46 this writing) in use. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 51 1.1 Terminology: Allocation or Assignment . . . . . . . . . . 3 52 2. Multicast Address Allocation . . . . . . . . . . . . . . . . . 4 53 2.1 Derived Allocation . . . . . . . . . . . . . . . . . . . . 4 54 2.1.1 GLOP Allocation . . . . . . . . . . . . . . . . . . . 4 55 2.1.2 Unicast-prefix -based Allocation . . . . . . . . . . . 4 56 2.2 Scope-relative Allocation . . . . . . . . . . . . . . . . 5 57 2.3 Static IANA Allocation . . . . . . . . . . . . . . . . . . 6 58 2.4 Dynamic Allocation . . . . . . . . . . . . . . . . . . . . 6 59 3. Multicast Address Assignment . . . . . . . . . . . . . . . . . 6 60 3.1 Derived Assignment . . . . . . . . . . . . . . . . . . . . 6 61 3.2 SSM Assignment inside the Node . . . . . . . . . . . . . . 7 62 3.3 Manually Configured Assignment . . . . . . . . . . . . . . 7 63 3.4 Static IANA Assignment . . . . . . . . . . . . . . . . . . 7 64 3.5 Dynamic Assignments . . . . . . . . . . . . . . . . . . . 8 65 3.6 Future Developments . . . . . . . . . . . . . . . . . . . 8 66 4. Multicast Address Discovery . . . . . . . . . . . . . . . . . 9 67 5. Summary and Future Directions . . . . . . . . . . . . . . . . 10 68 5.1 Prefix Allocation . . . . . . . . . . . . . . . . . . . . 10 69 5.2 Address Assignment . . . . . . . . . . . . . . . . . . . . 11 70 5.3 Future Actions . . . . . . . . . . . . . . . . . . . . . . 11 71 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 72 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 73 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 74 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 75 9.1 Normative References . . . . . . . . . . . . . . . . . . . . 12 76 9.2 Informative References . . . . . . . . . . . . . . . . . . . 13 77 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 15 78 A. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 15 79 Intellectual Property and Copyright Statements . . . . . . . . 16 81 1. Introduction 83 Good, up-to-date documentation of IP multicast is close to 84 non-existent. Particularly, this is an issue with multicast address 85 allocations (to networks and sites) and assignments (to hosts and 86 applications). This problem is stressed by the fact that there 87 exists confusing or misleading documentation on the subject 88 [RFC2908]. The consequence is that those who wish to learn of IP 89 multicast and how the addressing works do not get a clear view of the 90 current situation. 92 The aim of this document is to provide a brief overview of multicast 93 addressing and allocation techniques. The term 'addressing 94 architecture' refers to the set of addressing mechanisms and methods 95 in an informal manner. 97 It is important to note that Source-specific Multicast (SSM) 98 [I-D.ietf-ssm-arch] does not have these addressing problems; hence, 99 this document focuses on Any Source Multicast (ASM) model. The 100 applicability of SSM has been briefly discussed in 101 [I-D.ietf-mboned-ipv6-multicast-issues]. 103 This memo obsoletes RFC 2908 and RFC 2909 and re-classifies them 104 Historic. 106 1.1 Terminology: Allocation or Assignment 108 Almost all multicast documents and many other RFCs (such as DHCPv4 109 [RFC2131] and DHCPv6 [RFC3315]) have used the terms address 110 "allocation" and "assignment" interchangeably. However, the operator 111 and address management communities use these for two conceptually 112 different processes. 114 In unicast operations, address allocations refer to leasing a large 115 block of addresses from Internet Assigned Numbers Authority (IANA) to 116 a Regional Internet Registry (RIR), from RIR to a Local Internet 117 Registry (LIR) possibly through a National Internet Registry (NIR). 118 Address assignments, on the other hand, are the leases of smaller 119 address blocks or even single addresses to the end-user sites or 120 end-users themselves. 122 Therefore, in this memo, we will separate the two different 123 functions: "allocation" describes how larger blocks of addresses are 124 obtained by the network operators, and "assignment" describes how 125 applications, nodes or sets of nodes obtain a multicast address for 126 their use. 128 [[ NOTE IN DRAFT: is this choice of terminology too confusing? ]] 130 2. Multicast Address Allocation 132 Multicast address allocation, i.e., how a network operator might be 133 able to obtain a larger block of addresses, can be handled in a 134 number of ways as described below. 136 Note that these are all only pertinent to ASM -- SSM requires no 137 address block allocation because the group address has only local 138 significance (however, the address assignment inside the node is 139 still an issue discussed in Section 3.2). 141 2.1 Derived Allocation 143 Derived allocations take the unicast prefix or some other properties 144 of the network to determine unique multicast address allocations. 146 2.1.1 GLOP Allocation 148 GLOP address allocation [RFC3180] inserts the 16-bit public 149 Autonomous System (AS) number in the middle of the IPv4 multicast 150 prefix 233.0.0.0/8, so that each AS number can get a /24 worth of 151 multicast addresses. While this is sufficient for multicast testing 152 or small scale use, it might not be sufficient in all cases for 153 extensive multicast use. 155 A minor operational debugging issue with GLOP addresses is that the 156 connection between the AS and the prefix is not apparent from the 157 prefix, but has to be calculated (e.g., from [RFC3180], AS 5662 maps 158 to 233.22.30.0/24). A usage issue is that GLOP addresses are not 159 tied to any prefix but to routing domains, so they cannot be used or 160 calculated automatically. 162 2.1.2 Unicast-prefix -based Allocation 164 RFC 3306 [RFC3306] describes a mechanism which embeds up to 64 first 165 bits of an IPv6 unicast address in the prefix part of the IPv6 166 multicast address, leaving at least 32 bits of group-id space 167 available after the prefix mapping. 169 A similar mapping has been proposed for IPv4 170 [I-D.ietf-mboned-ipv4-uni-based-mcast], but it provides a rather low 171 amount of addresses (e.g., 1 per an IPv4 /24 block). While there 172 exist large networks without an AS number of their own, this has not 173 been seen to add sufficient value compared to GLOP addressing. 175 The IPv6 unicast-prefix -based allocations are an extremely useful 176 way to allow each network operator, even each subnet, obtain 177 multicast addresses easily, through an easy computation. Further, as 178 the IPv6 multicast header also includes the scope value [RFC3513], 179 multicast groups of smaller scope can also be used with the same 180 mapping. 182 The IPv6 Embedded RP technique [RFC3956], used with Protocol 183 Independent Multicast - Sparse Mode (PIM-SM), further leverages the 184 unicast prefix based allocations, by embedding the unicast prefix and 185 interface identifier of the PIM-SM Rendezvous Point (RP) in the 186 prefix. This provides all the necessary information needed to the 187 routing systems to run the group in either inter- or intra-domain 188 operation. A difference to RFC 3306 is, however, that the hosts 189 cannot calculate their "multicast prefix" automatically, as the 190 prefix depends on the decisions of the operator setting up the RP but 191 rather needs to be communicated somehow. 193 All the IPv6 unicast-prefix -based allocation techniques provide 194 sufficient amount of multicast address space for the network 195 operators. 197 2.2 Scope-relative Allocation 199 Administratively scoped multicast [RFC2365] is provided by two 200 different means: under 239.0.0.0/8 in IPv4 or by 4-bit encoding in 201 the IPv6 multicast address prefix [RFC3513]. 203 As IPv6 scope-relative allocations can be handled with unicast-prefix 204 -based multicast addressing as described in Section 2.1.2, and there 205 is no need for separate scope-relative allocations, we'll just 206 discuss IPv4 in this section. 208 The IPv4 scope-relative prefix 239.0.0.0/8 is further divided to 209 Local Scope (239.255.0.0/16) and Organization Local Scope 210 (239.192.0.0/14); other parts of the administrative scopes are either 211 reserved for expansion or undefined [RFC2365]. 213 Topologies which act under a single administration can easily use the 214 scoped multicast addresses for their internal groups. Groups which 215 need to be shared between multiple routing domains (but not 216 propagated through Internet) are more problematic and typically need 217 an assignment of a global multicast address because their scope is 218 undefined. 220 There is a large number of multicast applications (such as "Norton 221 Ghost") which are restricted either to a link or a site, but it is 222 extremely undesirable to propagate them further (either to the rest 223 of the site, or beyond the site). Typically many such applications 224 have been given a static IANA address assignment; this makes it 225 challenging to implement proper propagation limiting -- which could 226 be easier if such applications could have been assigned specific 227 scope-relative addresses instead. This is an area of further future 228 work -- it might be able to mitigate this issue if there was more 229 coordination inside the scope-relative allocation block. 231 2.3 Static IANA Allocation 233 In some rare cases, some organizations may have been able to obtain 234 static multicast address allocations directly from IANA. Typically 235 these have been meant as a block of static assignments to multicast 236 applications, as described in Section 3.4. In principle, IANA does 237 not allocate multicast address blocks to the operators but GLOP or 238 Unicast-prefix -based allocations should be used instead. 240 2.4 Dynamic Allocation 242 RFC 2908 [RFC2908] proposed three different layers of multicast 243 address allocation and assignment, where layers 3 (inter-domain 244 allocation) and layer 2 (intra-domain allocation) could be applicable 245 here. Multicast Address-Set Claim Protocol (MASC) [RFC2909] is an 246 example of the former, and Multicast Address Allocation Protocol 247 (AAP) [I-D.ietf-malloc-aap] (abandoned in 2000 due lack of interest 248 and technical problems) is an example of the latter. 250 Both of the proposed allocation protocols were quite complex, and 251 have never been deployed or seriously implemented. 253 It can be concluded that there are no dynamic multicast address 254 allocation protocols, and other methods such as GLOP or 255 unicast-prefix -based addressing should be used instead. 257 3. Multicast Address Assignment 259 For multicast address assignment, i.e., how an application learns the 260 address it can use, or a node (or a set of nodes) learns an address 261 it could use for an application, has a number of options as described 262 below. 264 Any IPv6 address assignment method should be aware of the guidelines 265 for the assignment of the group-IDs for IPv6 multicast addresses 266 [RFC3307]. 268 3.1 Derived Assignment 270 There are significantly fewer options for derived address assignment 271 compared to derived allocation. Derived multicast assignment is only 272 being specified for IPv6 link-scoped multicast 273 [I-D.ietf-ipv6-link-scoped-mcast], where the EUI64 is embedded in the 274 multicast address, providing a node with unique multicast addresses 275 for link-local ASM communications. 277 3.2 SSM Assignment inside the Node 279 While the SSM multicast addresses have only local (to the node) 280 significance, there is still a minor issue on how to assign the 281 addresses between the applications running on the same node (or more 282 precisely, an IP address). 284 This assignment is not considered to be a problem because typically 285 the addresses for the applications are selected manually or 286 statically, but if done using an API, the API could check that the 287 addresses do not conflict prior to assigning one. 289 3.3 Manually Configured Assignment 291 With manually configured assignment, the network operator which has a 292 multicast address prefix assigns the multicast group addresses to the 293 requesting nodes using a manual process. 295 Typically the user or administrator which wants to use a multicast 296 address for particular application requests an address from the 297 network operator using phone, email, or similar means, and the 298 network operator provides the user with a multicast address. Then 299 the user/administrator of the node or application manually configures 300 the application to use the assigned multicast address. 302 This is a relatively simple process in the beginning, but would 303 become unscalable if the multicast usage would get on a serious rise 304 (fortunately, we have dynamic assignment, see Section 3.5). Another, 305 separate issue is to ensure that the users wishing to use that 306 application are able to locate the configured multicast address 307 ("rendezvous" or "service discovery"); in this particular case, this 308 might call for e.g., DNS-based discovery of the multicast address. 310 This is the most commonly used technique when the multicast 311 application does not have a static IANA assignment. 313 3.4 Static IANA Assignment 315 In contrast to manually configured assignment, as described above, 316 static IANA assignment refers to getting a globally unique assignment 317 for the particular application directly from IANA. Guidelines for 318 IANA are described in [I-D.ietf-mboned-rfc3171bis]. 320 This is seen as lucrative because it's the simplest approach for 321 application developers because they can then hard-code the multicast 322 address, requiring no lease of the usable multicast address, and 323 likewise the client applications do not need to perform any kind of 324 service discovery (but depending on hard-coded addresses). However, 325 this is a bad approach architecturally, as we should focus on 326 enhancing and deploying service discovery and address assignment (as 327 needed) instead of encouraging a "land-grab" of multicast addresses. 329 In summary, there are applications which have obtained a static IANA 330 assignment, some of which are really needed, and some of which 331 probably should not have been granted. 333 3.5 Dynamic Assignments 335 The layer 1 of RFC 2908 [RFC2908] described dynamic assignment from 336 Multicast Address Allocation Servers (MAAS) to applications and 337 nodes, with Multicast Address Dynamic Client Allocation Protocol 338 (MADCAP) [RFC2730] and a proposal for DHCPv6 assignments 339 [I-D.jdurand-assign-addr-ipv6-multicast-dhcpv6] as examples. 341 Based on a multicast prefix, it would be rather straightforward to 342 deploy a dynamic assignment protocol which would lease group 343 addresses to the applications wishing to use multicast. For example, 344 only few have implemented MADCAP, and it's not significantly 345 deployed. Moreover, it is not clear how widely for example the APIs 346 for communication between the multicast application and the MADCAP 347 client operating at the host have been implemented [RFC2771]. 349 Based on that, a conclusion is that multicast is that either: 351 1. multicast is not significantly attractive in the first place, 353 2. manually configured assignments are sufficient for now, or 355 3. that there are other gaps why dynamic assignments are not seen as 356 a useful approach (for example, issues related to service 357 discovery/rendezvous). 359 In consequence, more work on rendezvous/service discovery will be 360 needed to make dynamic assignment more useful. 362 3.6 Future Developments 364 IPv6 could offer an alternative to dynamic assignments due to its 365 larger address space: if a multicast prefix (e.g., about 2^32 bits 366 worth of group-id's) is allocated to a subnet, it would be sufficient 367 to ensure that multiple applications running on that subnet do not 368 try to use the same address (selected e.g., using a random process). 369 This could call for a Duplicate Address Detection process, and/or a 370 way for the RPs to inform the hosts about the prefix that could be 371 used on each subnet (assuming Embedded-RP would be used). 373 4. Multicast Address Discovery 375 [[ NOTE IN DRAFT: it is not clear whether this section belongs in 376 this document at all; it is somewhat related, but could bear a more 377 extensive discussion elsewhere. It should likely go in a separate 378 document (if there was one discussing these problems!), or in an 379 appendix. Feedback is appreciated. ]] 381 As was noted in Section 3, multicast address discovery (i.e., service 382 discovery or "rendezvous") is a problem with multicast address 383 assignment. In particular, an acceptable mechanism (mechanisms such 384 as Service Location Protocol (SLP) [RFC2608] seem to have been 385 considered too complex) seems to be missing which the hosts wishing 386 to participate in a group could use to find the address of that group 387 [MBONED-IETF59]. 389 It is worth noting that as long as not deploying an address 390 assignment and service discovery protocols/mechanisms means that one 391 can get a static address assignment from IANA, there is little 392 interest from the application developers to actually do anything 393 except try to get the assignment from IANA. Conclusion: if we want 394 to use non-IANA processes, the assignments must be either forbidden 395 completely, or made sufficiently difficult that it's easier for the 396 application developers to take another route if a feasible mechanism 397 is available. 399 There are two issues in the service discovery: 401 1. The session initiator being able to publish the session somehow, 402 and 404 2. The session participants finding out about the session (rather 405 than creating their own). 407 When manually configured or static IANA assignments are used, 1) 408 should be relatively straightforward (if something needs to be 409 manually configured or statically assigned, putting it e.g., in DNS 410 should not be a problem). However, this is still more complex for 411 dynamic or derived assignments because it implies that the host or 412 the application has the right to make that publication on its own, 413 rather than through a manual process by an administrator. 415 2) is always a challenge, but could leverage for example DNS (e.g., 416 by relying on using SRV records with the DNS search path, as 417 described in [I-D.iab-dns-choices] and 419 [I-D.palet-v6ops-tun-auto-disc]). 421 5. Summary and Future Directions 423 This section summarizes the mechanisms and analysis discussed in this 424 memo, and presents some potential future directions. 426 5.1 Prefix Allocation 428 Summary of prefix allocation methods is in Figure 1. 430 +-------+--------------------------------+--------+--------+ 431 | Sect. | Prefix allocation method | IPv4 | IPv6 | 432 +-------+--------------------------------+--------+--------+ 433 | 2 | SSM | NoNeed | NoNeed | 434 | 2.1.1 | Derived: GLOP | Yes | NoNeed*| 435 | 2.1.2 | Derived: Unicast-prefix -based |No -yet | Yes | 436 | 2.2 | Separate Scope-relative | Yes | NoNeed*| 437 | 2.3 | Static IANA allocation | No | No | 438 | 2.4 | Dynamic allocation protocols | No | No | 439 +-------+--------------------------------+--------+--------+ 440 * = the need satisfied by IPv6 unicast-prefix -based allocation. 442 Figure 1 444 o Only ASM is affected by the assignment/allocation issues (however, 445 both ASM and SSM have roughly the same address discovery issues). 447 o GLOP allocations seem to provide a sufficient IPv4 multicast 448 allocation mechanism for now, but could be extended in future. 449 Scope-relative allocations provide the opportunity for internal 450 IPv4 allocations. 452 o Unicast-prefix -based addresses and the derivatives provide good 453 allocation strategy with IPv6, also for scoped multicast 454 addresses. 456 o Dynamic allocations are a too complex and unnecessary mechanism. 458 o Static IANA allocations are an architecturally unacceptable 459 approach. 461 5.2 Address Assignment 463 Summary of address assignment methods is in Figure 2. 465 +-------+--------------------------------+----------+----------+ 466 | Sect. | Address assignment method | IPv4 | IPv6 | 467 +-------+--------------------------------+----------+----------+ 468 | 3.1 | Derived: link-scope addresses | No | Yes | 469 | 3.2 | SSM (inside the node) | Yes | Yes | 470 | 3.3 | Manual assignment | Yes | Yes | 471 | 3.4 | Static IANA assignment |LastResort|LastResort| 472 | 3.5 | Dynamic assignment protocols | Yes | Yes | 473 +-------+--------------------------------+----------+----------+ 475 Figure 2 477 o Manually configured assignment is what's typically done today, and 478 works to a sufficient degree in smaller scale. 480 o Static IANA assignment has been done extensively in the past, but 481 it needs to be tightened down to prevent problems caused by 482 "land-grabbing". 484 o Dynamic assignment, e.g., using MADCAP have been implemented, but 485 there is no wide deployment, so a solution is there -- but either 486 there are other gaps in the multicast architecture or there is no 487 need for it in the first place, when manual configuration is 488 possible, and static IANA assignments are still there. 490 o Derived assignments are only applicable in a fringe case of 491 link-scoped multicast. 493 5.3 Future Actions 495 o Multicast address discovery/"rendezvous" needs to be analyzed at 496 more length, and an adequate solution provided; the result also 497 needs to be written down to be shown to the IANA static assignment 498 requestors. 500 o IPv6 multicast DAD and/or multicast prefix communication 501 mechanisms should be analyzed: whether there is demand or not, and 502 specify if so. 504 o The IETF should consider whether to specify more ranges of the 505 IPv4 scope-relative address space for static allocation for 506 applications which should not be routed over the Internet (such as 507 backup software, etc. -- so that these wouldn't need to use 508 global addresses which should never leak in any case). 510 o The IETF should seriously consider its static IANA allocations 511 policy, e.g., "locking it down" to a stricter policy (like "IETF 512 Consensus") and looking at developing the discovery/rendezvous 513 functions, if necessary. 515 6. Acknowledgements 517 Tutoring a couple multicast-related papers, the latest by Kaarle 518 Ritvanen [RITVANEN] convinced the author that the up-to-date 519 multicast address assignment/allocation documentation is necessary. 521 Multicast address allocations/assignments were discussed at the 522 MBONED WG session at IETF59 [MBONED-IETF59]. 524 Dave Thaler, James Lingard, and Beau Williamson provided useful 525 feedback for the preliminary version of this memo. Myung-Ki Shin 526 also suggested improvements. 528 7. IANA Considerations 530 This memo includes no request to IANA, but as the allocation and 531 assignment of multicast addresses are related to IANA functions, it 532 wouldn't hurt if the IANA reviewed this entire memo. 534 IANA considerations in sections 4.1.1 and 4.1.2 of [RFC2908] still 535 apply to the administratively scoped prefixes. 537 (RFC-editor: please remove this section at publication.) 539 8. Security Considerations 541 This memo only describes different approaches to allocating and 542 assigning multicast addresses, and this has no security 543 considerations; the security analysis of the mentioned protocols is 544 out of scope of this memo. 546 Obviously, especially the dynamic assignment protocols are inherently 547 vulnerable to resource exhaustion attacks, as discussed e.g., in 548 [RFC2730]. 550 9. References 552 9.1 Normative References 554 [I-D.ietf-ipv6-link-scoped-mcast] 555 Park, J., Shin, M. and H. Kim, "Link Scoped IPv6 Multicast 556 Addresses", draft-ietf-ipv6-link-scoped-mcast-06 (work in 557 progress), October 2004. 559 [I-D.ietf-mboned-rfc3171bis] 560 Albanna, Z., Almeroth, K., Cotton, M. and D. Meyer, "IANA 561 Guidelines for IPv4 Multicast Address Assignments", 562 draft-ietf-mboned-rfc3171bis-02 (work in progress), March 563 2004. 565 [I-D.ietf-ssm-arch] 566 Holbrook, H. and B. Cain, "Source-Specific Multicast for 567 IP", draft-ietf-ssm-arch-06 (work in progress), September 568 2004. 570 [RFC2365] Meyer, D., "Administratively Scoped IP Multicast", BCP 23, 571 RFC 2365, July 1998. 573 [RFC3180] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", BCP 574 53, RFC 3180, September 2001. 576 [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 577 Multicast Addresses", RFC 3306, August 2002. 579 [RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast 580 Addresses", RFC 3307, August 2002. 582 [RFC3513] Hinden, R. and S. Deering, "Internet Protocol Version 6 583 (IPv6) Addressing Architecture", RFC 3513, April 2003. 585 [RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous 586 Point (RP) Address in an IPv6 Multicast Address", RFC 587 3956, November 2004. 589 9.2 Informative References 591 [I-D.iab-dns-choices] 592 Faltstrom, P. and R. Austein, "Design Choices When 593 Expanding DNS", draft-iab-dns-choices-00 (work in 594 progress), October 2004. 596 [I-D.ietf-malloc-aap] 597 Handley, M. and S. Hanna, "Multicast Address Allocation 598 Protocol (AAP)", June 2000. 600 [I-D.ietf-mboned-ipv4-uni-based-mcast] 601 Thaler, D., "Unicast-Prefix-based IPv4 Multicast 602 Addresses", draft-ietf-mboned-ipv4-uni-based-mcast-02 603 (work in progress), October 2004. 605 [I-D.ietf-mboned-ipv6-multicast-issues] 606 Savola, P., "IPv6 Multicast Deployment Issues", 607 draft-ietf-mboned-ipv6-multicast-issues-01 (work in 608 progress), September 2004. 610 [I-D.jdurand-assign-addr-ipv6-multicast-dhcpv6] 611 Durand, J., "IPv6 multicast address assignment with 612 DHCPv6", 613 draft-jdurand-assign-addr-ipv6-multicast-dhcpv6-00 (work 614 in progress), June 2004. 616 [I-D.palet-v6ops-tun-auto-disc] 617 Palet, J. and M. Diaz, "Analysis of IPv6 Tunnel End-point 618 Discovery Mechanisms", draft-palet-v6ops-tun-auto-disc-02 619 (work in progress), October 2004. 621 [MBONED-IETF59] 622 "MBONED WG session at IETF59", 623 . 625 [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 626 2131, March 1997. 628 [RFC2608] Guttman, E., Perkins, C., Veizades, J. and M. Day, 629 "Service Location Protocol, Version 2", RFC 2608, June 630 1999. 632 [RFC2730] Hanna, S., Patel, B. and M. Shah, "Multicast Address 633 Dynamic Client Allocation Protocol (MADCAP)", RFC 2730, 634 December 1999. 636 [RFC2771] Finlayson, R., "An Abstract API for Multicast Address 637 Allocation", RFC 2771, February 2000. 639 [RFC2908] Thaler, D., Handley, M. and D. Estrin, "The Internet 640 Multicast Address Allocation Architecture", RFC 2908, 641 September 2000. 643 [RFC2909] Radoslavov, P., Estrin, D., Govindan, R., Handley, M., 644 Kumar, S. and D. Thaler, "The Multicast Address-Set Claim 645 (MASC) Protocol", RFC 2909, September 2000. 647 [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C. and 648 M. Carney, "Dynamic Host Configuration Protocol for IPv6 649 (DHCPv6)", RFC 3315, July 2003. 651 [RITVANEN] 652 Ritvanen, K., "Multicast Routing and Addressing", HUT 653 Report, Seminar on Internetworking, May 2004, 654 . 656 Author's Address 658 Pekka Savola 659 CSC - Scientific Computing Ltd. 660 Espoo 661 Finland 663 EMail: psavola@funet.fi 665 Appendix A. Open Issues 667 (This section will be removed or merged with the rest before 668 publication..) 670 o Is the case for IPv4 Unicast-Prefix Base Multicast addressing 671 sufficiently strong, or could those organizations just get an AS 672 number themselves if they really wanted to do multicast? 674 o Should one merge the routing architecture document's contents here 675 as well? 677 Intellectual Property Statement 679 The IETF takes no position regarding the validity or scope of any 680 Intellectual Property Rights or other rights that might be claimed to 681 pertain to the implementation or use of the technology described in 682 this document or the extent to which any license under such rights 683 might or might not be available; nor does it represent that it has 684 made any independent effort to identify any such rights. 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