diff options
Diffstat (limited to 'doc/rfc/rfc6308.txt')
-rw-r--r-- | doc/rfc/rfc6308.txt | 787 |
1 files changed, 787 insertions, 0 deletions
diff --git a/doc/rfc/rfc6308.txt b/doc/rfc/rfc6308.txt new file mode 100644 index 0000000..b5c0fb7 --- /dev/null +++ b/doc/rfc/rfc6308.txt @@ -0,0 +1,787 @@ + + + + + + +Internet Engineering Task Force (IETF) P. Savola +Request for Comments: 6308 CSC/FUNET +Obsoletes: 2908 June 2011 +Category: Informational +ISSN: 2070-1721 + + + Overview of the Internet Multicast Addressing Architecture + +Abstract + + The lack of up-to-date documentation on IP multicast address + allocation and assignment procedures has caused a great deal of + confusion. To clarify the situation, this memo describes the + allocation and assignment techniques and mechanisms currently (as of + this writing) in use. + +Status of This Memo + + This document is not an Internet Standards Track specification; it is + published for informational purposes. + + This document is a product of the Internet Engineering Task Force + (IETF). It represents the consensus of the IETF community. It has + received public review and has been approved for publication by the + Internet Engineering Steering Group (IESG). Not all documents + approved by the IESG are a candidate for any level of Internet + Standard; see Section 2 of RFC 5741. + + Information about the current status of this document, any errata, + and how to provide feedback on it may be obtained at + http://www.rfc-editor.org/info/rfc6308. + +Copyright Notice + + Copyright (c) 2011 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents + (http://trustee.ietf.org/license-info) in effect on the date of + publication of this document. Please review these documents + carefully, as they describe your rights and restrictions with respect + to this document. Code Components extracted from this document must + include Simplified BSD License text as described in Section 4.e of + the Trust Legal Provisions and are provided without warranty as + described in the Simplified BSD License. + + + + +Savola Informational [Page 1] + +RFC 6308 Multicast Address Allocation June 2011 + + +Table of Contents + + 1. Introduction ....................................................2 + 1.1. Terminology: Allocation or Assignment ......................3 + 2. Multicast Address Allocation ....................................3 + 2.1. Derived Allocation .........................................3 + 2.1.1. GLOP Allocation .....................................4 + 2.1.2. Unicast-Prefix-Based Allocation .....................4 + 2.2. Administratively Scoped Allocation .........................5 + 2.3. Static IANA Allocation .....................................6 + 2.4. Dynamic Allocation .........................................6 + 3. Multicast Address Assignment ....................................6 + 3.1. Derived Assignment .........................................6 + 3.2. SSM Assignment inside the Node .............................7 + 3.3. Manually Configured Assignment .............................7 + 3.4. Static IANA Assignment .....................................7 + 3.4.1. Global IANA Assignment ..............................7 + 3.4.2. Scope-Relative IANA Assignment ......................8 + 3.5. Dynamic Assignments ........................................8 + 4. Summary and Future Directions ...................................9 + 4.1. Prefix Allocation ..........................................9 + 4.2. Address Assignment ........................................10 + 4.3. Future Actions ............................................11 + 5. Acknowledgements ...............................................11 + 6. IANA Considerations ............................................11 + 7. Security Considerations ........................................11 + 8. References .....................................................12 + 8.1. Normative References ......................................12 + 8.2. Informative References ....................................13 + +1. Introduction + + Good, up-to-date documentation of IP multicast is close to + non-existent. Particularly, this is an issue with multicast address + allocations (to networks and sites) and assignments (to hosts and + applications). This problem is stressed by the fact that there + exists confusing or misleading documentation on the subject + [RFC2908]. The consequence is that those who wish to learn about IP + multicast and how the addressing works do not get a clear view of the + current situation. + + The aim of this document is to provide a brief overview of multicast + addressing and allocation techniques. The term "addressing + architecture" refers to the set of addressing mechanisms and methods + in an informal manner. + + + + + + +Savola Informational [Page 2] + +RFC 6308 Multicast Address Allocation June 2011 + + + It is important to note that Source-Specific Multicast (SSM) + [RFC4607] does not have these addressing problems because SSM group + addresses have only local significance; hence, this document focuses + on the Any Source Multicast (ASM) model. + + This memo obsoletes and re-classifies RFC 2908 to Historic, and + re-classifies RFCs 2776 and 2909 to Historic. + +1.1. Terminology: Allocation or Assignment + + Almost all multicast documents and many other RFCs (such as DHCPv4 + [RFC2131] and DHCPv6 [RFC3315]) have used the terms "address + allocation" and "address assignment" interchangeably. However, the + operator and address management communities use these terms for two + conceptually different processes. + + In unicast operations, address allocations refer to leasing a large + block of addresses from the Internet Assigned Numbers Authority + (IANA) to a Regional Internet Registry (RIR), or from an RIR to a + Local Internet Registry (LIR), possibly through a National Internet + Registry (NIR). Address assignments, on the other hand, are the + leases of smaller address blocks or even single addresses to the end- + user sites or end-users themselves. + + Therefore, in this memo, we will separate the two different + functions: "allocation" describes how larger blocks of addresses are + obtained by the network operators, and "assignment" describes how + applications, nodes, or sets of nodes obtain a multicast address for + their use. + +2. Multicast Address Allocation + + Multicast address allocation, i.e., how a network operator might be + able to obtain a larger block of addresses, can be handled in a + number of ways, as described below. + + Note that these are all only pertinent to ASM -- SSM requires no + address block allocation because the group address has only local + significance (however, we discuss the address assignment inside the + node in Section 3.2). + +2.1. Derived Allocation + + Derived allocations take the unicast prefix or some other properties + of the network (e.g., an autonomous system (AS) number) to determine + unique multicast address allocations. + + + + + +Savola Informational [Page 3] + +RFC 6308 Multicast Address Allocation June 2011 + + +2.1.1. GLOP Allocation + + GLOP address allocation [RFC3180] inserts the 16-bit public AS number + in the middle of the IPv4 multicast prefix 233.0.0.0/8, so that each + AS number can get a /24 worth of multicast addresses. While this is + sufficient for multicast testing or small-scale use, it might not be + sufficient in all cases for extensive multicast use. + + A minor operational debugging issue with GLOP addresses is that the + connection between the AS and the prefix is not apparent from the + prefix when the AS number is greater than 255, but has to be + calculated (e.g., as described in [RFC3180], AS 5662 maps to + 233.22.30.0/24). A usage issue is that GLOP addresses are not tied + to any prefix but to routing domains, so they cannot be used or + calculated automatically. + + GLOP mapping is not available with 4-byte AS numbers [RFC4893]. + Unicast-prefix-based allocation or an IANA allocation from "AD-HOC + Block III" (the previous so-called "EGLOP" (Extended GLOP) block) + could be used instead, as needed. + + The GLOP allocation algorithm has not been defined for IPv6 multicast + because the unicast-prefix-based allocation (described below) + addresses the same need in a simpler fashion. + +2.1.2. Unicast-Prefix-Based Allocation + + RFC 3306 [RFC3306] describes a mechanism that embeds up to 64 high- + order bits of an IPv6 unicast address in the prefix part of the IPv6 + multicast address, leaving at least 32 bits of group-id space + available after the prefix mapping. + + A similar IPv4 mapping is described in [RFC6034], but it provides a + limited number of addresses (e.g., 1 per IPv4 /24 block). + + The IPv6 unicast-prefix-based allocations are an extremely useful way + to allow each network operator, even each subnet, to obtain multicast + addresses easily, through an easy computation. Further, as the IPv6 + multicast header also includes the scope value [RFC4291], multicast + groups of smaller scope can also be used with the same mapping. + + The IPv6 Embedded Rendezvous Point (RP) technique [RFC3956], used + with Protocol Independent Multicast - Sparse Mode (PIM-SM), further + leverages the unicast-prefix-based allocations, by embedding the + unicast prefix and interface identifier of the PIM-SM RP in the + prefix. This provides all the necessary information needed to the + routing systems to run the group in either inter- or intra-domain + operation. A difference from RFC 3306 is, however, that the hosts + + + +Savola Informational [Page 4] + +RFC 6308 Multicast Address Allocation June 2011 + + + cannot calculate their "multicast prefix" automatically (as the + prefix depends on the decisions of the operator setting up the RP), + but instead require an assignment method. + + All the IPv6 unicast-prefix-based allocation techniques provide a + sufficient amount of multicast address space for network operators. + +2.2. Administratively Scoped Allocation + + Administratively scoped multicast address allocation [RFC2365] is + provided by two different means: under 239.0.0.0/8 in IPv4 or by + 4-bit encoding in the IPv6 multicast address prefix [RFC4291]. + + Since IPv6 administratively scoped allocations can be handled with + unicast-prefix-based multicast addressing as described in + Section 2.1.2, we'll only discuss IPv4 in this section. + + The IPv4 administratively scoped prefix 239.0.0.0/8 is further + divided into Local Scope (239.255.0.0/16) and Organization Local + Scope (239.192.0.0/14); other parts of the administrative scopes are + either reserved for expansion or undefined [RFC2365]. However, + RFC 2365 is ambiguous as to whether the enterprises or the IETF are + allowed to expand the space. + + Topologies that act under a single administration can easily use the + scoped multicast addresses for their internal groups. Groups that + need to be shared between multiple routing domains (even if not + propagated through the Internet) are more problematic and typically + need an assignment of a global multicast address because their scope + is undefined. + + There are a large number of multicast applications (such as "Norton + Ghost") that are restricted either to a link or a site, and it is + extremely undesirable to propagate them further (beyond the link or + the site). Typically, many such applications have been given or have + hijacked a static IANA address assignment. Given the fact that + assignments to typically locally used applications come from the same + range as global applications, implementing proper propagation + limiting is challenging. Filtering would be easier if a separate, + identifiable range would be used for such assignments in the future; + this is an area of further future work. + + There has also been work on a protocol to automatically discover + multicast scope zones [RFC2776], but it has never been widely + implemented or deployed. + + + + + + +Savola Informational [Page 5] + +RFC 6308 Multicast Address Allocation June 2011 + + +2.3. Static IANA Allocation + + In some rare cases, organizations may have been able to obtain static + multicast address allocations (of up to 256 addresses) directly from + IANA. Typically, these have been meant as a block of static + assignments to multicast applications, as described in Section 3.4.1. + If another means of obtaining addresses is available, that approach + is preferable. + + Especially for those operators that only have a 32-bit AS number and + need IPv4 addresses, an IANA allocation from "AD-HOC Block III" (the + previous so-called "EGLOP" block) is an option [RFC5771]. + +2.4. Dynamic Allocation + + RFC 2908 [RFC2908] proposed three different layers of multicast + address allocation and assignment, where layer 3 (inter-domain + allocation) and layer 2 (intra-domain allocation) could be applicable + here. The Multicast Address-Set Claim Protocol (MASC) [RFC2909] is + an example of the former, and the Multicast Address Allocation + Protocol (AAP) [MALLOC-AAP] (abandoned in 2000 due to lack of + interest and technical problems) is an example of the latter. + + Both of the proposed allocation protocols were quite complex, and + have never been deployed or seriously implemented. + + It can be concluded that dynamic multicast address allocation + protocols provide no benefit beyond GLOP/unicast-prefix-based + mechanisms and have been abandoned. + +3. Multicast Address Assignment + + There are a number of possible ways for an application, node, or set + of nodes to learn a multicast address, as described below. + + Any IPv6 address assignment method should be aware of the guidelines + for the assignment of group-IDs for IPv6 multicast addresses + [RFC3307]. + +3.1. Derived Assignment + + There are significantly fewer options for derived address assignment + compared to derived allocation. Derived multicast assignment has + only been specified for IPv6 link-scoped multicast [RFC4489], where + the EUI64 is embedded in the multicast address, providing a node with + unique multicast addresses for link-local ASM communications. + + + + + +Savola Informational [Page 6] + +RFC 6308 Multicast Address Allocation June 2011 + + +3.2. SSM Assignment inside the Node + + While SSM multicast addresses have only local (to the node) + significance, there is still a minor issue on how to assign the + addresses between the applications running on the same IP address. + + This assignment is not considered to be a problem, because typically + the addresses for these applications are selected manually or + statically, but if done using an Application Programming Interface + (API), the API could check that the addresses do not conflict prior + to assigning one. + +3.3. Manually Configured Assignment + + With manually configured assignment, a network operator who has a + multicast address prefix assigns the multicast group addresses to the + requesting nodes using a manual process. + + Typically, the user or administrator that wants to use a multicast + address for a particular application requests an address from the + network operator using phone, email, or similar means, and the + network operator provides the user with a multicast address. Then + the user/administrator of the node or application manually configures + the application to use the assigned multicast address. + + This is a relatively simple process; it has been sufficient for + certain applications that require manual configuration in any case, + or that cannot or do not want to justify a static IANA assignment. + The manual assignment works when the number of participants in a + group is small, as each participant has to be manually configured. + + This is the most commonly used technique when the multicast + application does not have a static IANA assignment. + +3.4. Static IANA Assignment + + In contrast to manually configured assignment, as described above, + static IANA assignment refers to getting an assignment for the + particular application directly from IANA. There are two main forms + of IANA assignment: global and scope-relative. Guidelines for IANA + are described in [RFC5771]. + +3.4.1. Global IANA Assignment + + Globally unique address assignment is seen as lucrative because it's + the simplest approach for application developers, since they can then + hard-code the multicast address. Hard-coding requires no lease of + the usable multicast address, and likewise the client applications do + + + +Savola Informational [Page 7] + +RFC 6308 Multicast Address Allocation June 2011 + + + not need to perform any kind of service discovery (but depend on + hard-coded addresses). However, there is an architectural scaling + problem with this approach, as it encourages a "land-grab" of the + limited multicast address space. + +3.4.2. Scope-Relative IANA Assignment + + IANA also assigns numbers as an integer offset from the highest + address in each IPv4 administrative scope, as described in [RFC2365]. + For example, the SLPv2 discovery scope-relative offset is "2", so the + SLPv2 discovery address within IPv4 Local-Scope (239.255.0.0/16) is + "239.255.255.253"; within the IPv4 Organization Local-Scope + (239.192.0.0/14), it is "239.195.255.253"; and so on. + + Similar scope-relative assignments also exist with IPv6 [RFC2375]. + As IPv6 multicast addresses have much more flexible scoping, scope- + relative assignments are also applicable to global scopes. The + assignment policies are described in [RFC3307]. + +3.5. Dynamic Assignments + + Layer 1 as defined in RFC 2908 [RFC2908] described dynamic assignment + from Multicast Address Allocation Servers (MAAS) to applications and + nodes, with the Multicast Address Dynamic Client Allocation Protocol + (MADCAP) [RFC2730] as an example. Since then, other mechanisms have + also been proposed (e.g., DHCPv6 assignment + [MCAST-DHCPv6]), but these have not gained traction. + + It would be rather straightforward to deploy a dynamic assignment + protocol that would lease group addresses based on a multicast prefix + to applications wishing to use multicast. However, only few have + implemented MADCAP (i.e., it is not significantly deployed). It is + not clear if the sparse deployment is due to a lack of need for the + protocol. Moreover, it is not clear how widely, for example, the + APIs for communication between the multicast application and the + MADCAP client operating at the host have been implemented [RFC2771]. + + An entirely different approach is the Session Announcement Protocol + (SAP) [RFC2974]. In addition to advertising global multicast + sessions, the protocol also has associated ranges of addresses for + both IPv4 and IPv6 that can be used by SAP-aware applications to + create new groups and new group addresses. Creating a session (and + obtaining an address) is a rather tedious process, which is why it + isn't done all that often. It is also worth noting that the IPv6 SAP + address is unroutable in the inter-domain multicast. + + + + + + +Savola Informational [Page 8] + +RFC 6308 Multicast Address Allocation June 2011 + + + Conclusions about dynamic assignment protocols are that: + + 1. multicast is not significantly attractive in the first place, + + 2. most applications have a static IANA assignment and thus require + no dynamic or manual assignment, + + 3. those applications that cannot be easily satisfied with IANA or + manual assignment (i.e., where dynamic assignment would be + desirable) are rather marginal, or + + 4. there are other reasons why dynamic assignments are not seen as a + useful approach (for example, issues related to service + discovery/rendezvous). + + In consequence, more work on rendezvous/service discovery would be + needed to make dynamic assignments more useful. + +4. Summary and Future Directions + + This section summarizes the mechanisms and analysis discussed in this + memo, and presents some potential future directions. + +4.1. Prefix Allocation + + A summary of prefix allocation methods for ASM is shown in Figure 1. + + +-------+--------------------------------+--------+--------+ + | Sect. | Prefix allocation method | IPv4 | IPv6 | + +-------+--------------------------------+--------+--------+ + | 2.1.1 | Derived: GLOP | Yes | NoNeed*| + | 2.1.2 | Derived: Unicast-prefix-based | No | Yes | + | 2.2 | Administratively scoped | Yes | NoNeed*| + | 2.3 | Static IANA allocation | Yes** | No | + | 2.4 | Dynamic allocation protocols | No | No | + +-------+--------------------------------+--------+--------+ + * = the need satisfied by IPv6 unicast-prefix-based allocation + ** = mainly using the AD-HOC block III (formerly called "EGLOP") + + Figure 1 + + + + + + + + + + + +Savola Informational [Page 9] + +RFC 6308 Multicast Address Allocation June 2011 + + + o Only ASM is affected by the assignment/allocation issues. + + o With IPv4, GLOP allocations provide a sufficient IPv4 multicast + allocation mechanism for those that have a 16-bit AS number. IPv4 + unicast-prefix-based allocation offers some addresses. IANA is + also allocating from the AD-HOC block III (formerly called + "EGLOP"), especially with 32-bit AS number holders in mind. + Administratively scoped allocations provide the opportunity for + internal IPv4 allocations. + + o With IPv6, unicast-prefix-based addresses and the derivatives + provide a good allocation strategy, and this also works for scoped + multicast addresses. + + o Dynamic allocations are too complex and unnecessary a mechanism. + +4.2. Address Assignment + + A summary of address assignment methods is shown in Figure 2. + + +--------+--------------------------------+----------+----------+ + | Sect. | Address assignment method | IPv4 | IPv6 | + +--------+--------------------------------+----------+----------+ + | 3.1 | Derived: link-scope addresses | No | Yes | + | 3.2 | SSM (inside the node) | Yes | Yes | + | 3.3 | Manual assignment | Yes | Yes | + | 3.4.1 | Global IANA/RIR assignment |LastResort|LastResort| + | 3.4.2 | Scope-relative IANA assignment | Yes | Yes | + | 3.5 | Dynamic assignment protocols | Yes | Yes | + +--------+--------------------------------+----------+----------+ + + Figure 2 + + o Manually configured assignment is typical today, and works to a + sufficient degree in smaller scale. + + o Global IANA assignment has been done extensively in the past. + Scope-relative IANA assignment is acceptable, but the size of the + pool is not very high. Inter-domain routing of IPv6 IANA-assigned + prefixes is likely going to be challenging, and as a result that + approach is not very appealing. + + o Dynamic assignment, e.g., MADCAP, has been implemented, but there + is no wide deployment. Therefore, either there are other gaps in + the multicast architecture, or there is no sufficient demand for + it in the first place when manual and static IANA assignments are + available. Assignments using SAP also exist but are not common; + global SAP assignment is infeasible with IPv6. + + + +Savola Informational [Page 10] + +RFC 6308 Multicast Address Allocation June 2011 + + + o Derived assignments are only applicable in a fringe case of link- + scoped multicast. + +4.3. Future Actions + + o Multicast address discovery/"rendezvous" needs to be analyzed at + more length, and an adequate solution provided. See + [ADDRDISC-PROB] and [MSA-REQ] for more information. + + o The IETF should consider whether to specify more ranges of the + IPv4 administratively scoped address space for static allocation + for applications that should not be routed over the Internet (such + as backup software, etc. -- so that these wouldn't need to use + global addresses, which should never leak in any case). + + o The IETF should consider its static IANA allocations policy, e.g., + "locking it down" to a stricter policy (like "IETF Consensus") and + looking at developing the discovery/rendezvous functions, if + necessary. + +5. Acknowledgements + + Tutoring a couple of multicast-related papers, the latest by Kaarle + Ritvanen [RITVANEN], convinced the author that updated multicast + address assignment/allocation documentation is needed. + + Multicast address allocations/assignments were discussed at the + MBONED WG session at IETF 59 [MBONED-IETF59]. + + Dave Thaler, James Lingard, and Beau Williamson provided useful + feedback for the preliminary version of this memo. Myung-Ki Shin, + Jerome Durand, John Kristoff, Dave Price, Spencer Dawkins, and Alfred + Hoenes also suggested improvements. + +6. IANA Considerations + + IANA considerations in Sections 4.1.1 and 4.1.2 of obsoleted and now + Historic [RFC2908] were never implemented in the IANA registry. + +7. Security Considerations + + This memo only describes different approaches to allocating and + assigning multicast addresses, and this has no security + considerations; the security analysis of the mentioned protocols is + out of scope of this memo. + + + + + + +Savola Informational [Page 11] + +RFC 6308 Multicast Address Allocation June 2011 + + + Obviously, the dynamic assignment protocols in particular are + inherently vulnerable to resource exhaustion attacks, as discussed, + e.g., in [RFC2730]. + +8. References + +8.1. Normative References + + [RFC2365] Meyer, D., "Administratively Scoped IP Multicast", + BCP 23, RFC 2365, July 1998. + + [RFC3180] Meyer, D. and P. Lothberg, "GLOP Addressing in 233/8", + BCP 53, RFC 3180, September 2001. + + [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 + Multicast Addresses", RFC 3306, August 2002. + + [RFC3307] Haberman, B., "Allocation Guidelines for IPv6 Multicast + Addresses", RFC 3307, August 2002. + + [RFC3956] Savola, P. and B. Haberman, "Embedding the Rendezvous + Point (RP) Address in an IPv6 Multicast Address", + RFC 3956, November 2004. + + [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing + Architecture", RFC 4291, February 2006. + + [RFC4489] Park, J-S., Shin, M-K., and H-J. Kim, "A Method for + Generating Link-Scoped IPv6 Multicast Addresses", + RFC 4489, April 2006. + + [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for + IP", RFC 4607, August 2006. + + [RFC5771] Cotton, M., Vegoda, L., and D. Meyer, "IANA Guidelines + for IPv4 Multicast Address Assignments", BCP 51, + RFC 5771, March 2010. + + [RFC6034] Thaler, D., "Unicast-Prefix-Based IPv4 Multicast + Addresses", RFC 6034, October 2010. + + + + + + + + + + + +Savola Informational [Page 12] + +RFC 6308 Multicast Address Allocation June 2011 + + +8.2. Informative References + + [ADDRDISC-PROB] + Savola, P., "Lightweight Multicast Address Discovery + Problem Space", Work in Progress, March 2006. + + [MALLOC-AAP] + Handley, M. and S. Hanna, "Multicast Address Allocation + Protocol (AAP)", Work in Progress, June 2000. + + [MBONED-IETF59] + "MBONED WG session at IETF59", + <http://www.ietf.org/proceedings/04mar/172.htm>. + + [MCAST-DHCPv6] + Durand, J., "IPv6 multicast address assignment with + DHCPv6", Work in Progress, February 2005. + + [MSA-REQ] Asaeda, H. and V. Roca, "Requirements for IP Multicast + Session Announcement", Work in Progress, March 2010. + + [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", + RFC 2131, March 1997. + + [RFC2375] Hinden, R. and S. Deering, "IPv6 Multicast Address + Assignments", RFC 2375, July 1998. + + [RFC2730] Hanna, S., Patel, B., and M. Shah, "Multicast Address + Dynamic Client Allocation Protocol (MADCAP)", RFC 2730, + December 1999. + + [RFC2771] Finlayson, R., "An Abstract API for Multicast Address + Allocation", RFC 2771, February 2000. + + [RFC2776] Handley, M., Thaler, D., and R. Kermode, "Multicast-Scope + Zone Announcement Protocol (MZAP)", RFC 2776, February + 2000. + + [RFC2908] Thaler, D., Handley, M., and D. Estrin, "The Internet + Multicast Address Allocation Architecture", RFC 2908, + September 2000. + + [RFC2909] Radoslavov, P., Estrin, D., Govindan, R., Handley, M., + Kumar, S., and D. Thaler, "The Multicast Address-Set + Claim (MASC) Protocol", RFC 2909, September 2000. + + [RFC2974] Handley, M., Perkins, C., and E. Whelan, "Session + Announcement Protocol", RFC 2974, October 2000. + + + +Savola Informational [Page 13] + +RFC 6308 Multicast Address Allocation June 2011 + + + [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, + C., and M. Carney, "Dynamic Host Configuration Protocol + for IPv6 (DHCPv6)", RFC 3315, July 2003. + + [RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS + Number Space", RFC 4893, May 2007. + + [RITVANEN] Ritvanen, K., "Multicast Routing and Addressing", HUT + Report, Seminar on Internetworking, May 2004, + <http://www.tml.hut.fi/Studies/T-110.551/2004/papers/>. + +Author's Address + + Pekka Savola + CSC - Scientific Computing Ltd. + Espoo + Finland + + EMail: psavola@funet.fi + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Savola Informational [Page 14] + |