PIM WG A. Boers Internet-Draft IJ. Wijnands Expires: August 5, 2005 E. Rosen Cisco Systems, Inc. february 2005 Format for using PIM proxies draft-ietf-pim-proxy-00 Status of this Memo This document is an Internet-Draft and is subject to all provisions of Section 3 of RFC 3667. By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she become aware will be disclosed, in accordance with RFC 3668. 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. This Internet-Draft will expire on August 5, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This document describes a generic TLV encoding format to be added to PIM. Boers, et al. Expires August 5, 2005 [Page 1] Internet-Draft The PIM Proxy format february 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Use of the Proxy Field in Join Messages . . . . . . . . . . . 3 2.1 Proxy join . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 Transitive proxies . . . . . . . . . . . . . . . . . . . . 3 2.3 Proxy Hello Option . . . . . . . . . . . . . . . . . . . . 3 2.4 Conflicting Proxies . . . . . . . . . . . . . . . . . . . 3 2.5 Proxy Convergence . . . . . . . . . . . . . . . . . . . . 4 2.6 Multiple Proxies . . . . . . . . . . . . . . . . . . . . . 4 3. PIM Proxy packet format . . . . . . . . . . . . . . . . . . . 5 3.1 PIM Join packet format . . . . . . . . . . . . . . . . . . 5 3.2 PIM Proxy Hello option . . . . . . . . . . . . . . . . . . 5 4. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1 Normative References . . . . . . . . . . . . . . . . . . . 6 5.2 Informative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 6 Intellectual Property and Copyright Statements . . . . . . . . 7 Boers, et al. Expires August 5, 2005 [Page 2] Internet-Draft The PIM Proxy format february 2005 1. Introduction It is sometimes convenient to add additional information to PIM join messages. The generic PIM encoding format is not allways optimal todo this. This document defines a new field in the PIM Join message, called the "Proxy" field. The contents and purpose of this proxy field is not outside the scope of this document, only the generic encoding format is described here. 2. Use of the Proxy Field in Join Messages 2.1 Proxy join Proxy fields are defined similar to the PIM source encoding type as defined in [I-D.ietf-pim-sm-v2-new]. A source address without any additional TLV's should be processed identically to a source address in the default source encoding. Multiple TLV's from the same or different type are permitted in a single source address in any order. 2.2 Transitive proxies It may be desired to have routers that understand the generic proxy format, forward the proxies regardless if they understand the TLV's encoded in the proxy not. For this the first bit in the Type field is reserved. If this bit is set then the TLV is forwarded upstream in case the router does not understand that type. 2.3 Proxy Hello Option A new PIM source type has been defined to include the Proxy field. This source type is included in a normal PIM Join. Each router on a connected network needs to be able to understand and parse the Join message. Therefore we include a new PIM hello option to advertise our capability to parse and process the new source type. We can only send a PIM Join which includes a Proxy if ALL routers on the network support the new option. (Even a router which is not the upstream neighbor must be able parse the packet in order to do Join suppression or overriding.) Option value TBD. 2.4 Conflicting Proxies It's possible that a router receives conflicting proxy information from different downstream routers. See Figure 2. Boers, et al. Expires August 5, 2005 [Page 3] Internet-Draft The PIM Proxy format february 2005 ( Edge A1 ) ( Edge B1 )---- [R1] / \ / / \ / [S] ( Core ) \ / \ \ / \ ( Edge A2 ) ( Edge B2 )---- [R2] Figure 2 There are 2 receivers for the same group connected to Edge B1 and B2. Suppose that edge router B1 prefers A1 as the exit point and B2 prefers A2 as exit point to reach the source S. If both Edge B1 and B2 send a Join including a Proxy to prefer their exit router in the network and they cross the same core router, the core router will get conflicting proxy information for the source. If this happens we use the Proxy from the PIM adjacency with the numerically smallest IP address. The Proxies from other sending routers may be kept around in case the best Proxy gets pruned or expires, we are able to immediately use the second best Proxy and converge quickly without waiting for the next periodic update. If a TLV has its own definition for conflict resolution is is preferred over the conflict resolution above. 2.5 Proxy Convergence A Proxy is included in a PIM Join message together with the source information. If the Proxy for this source is changed, we trigger a new PIM Join message to the upstream router. This causes the new Proxy to be propagated. This new Proxy implicitly removes the old Proxy upstream. If processing the new Proxy results in a change in the distribution tree, a PIM Prune message may be sent. This PIM Prune does not need to carry any Proxy, the sender of the prune and the source and group information is enough to identify the entry. The proxy information is removed immediately and possibly a new proxy is chosen from the database if available. 2.6 Multiple Proxies A PIM Join can contain multiple Proxies. The Proxies are encoded as TLVs associated with a new PIM source type in the PIM message. When a PIM Join with multiple Proxies is received, the first Proxy is processed, and the action taken depends upon the Proxy type. This may or may not result in the processing of the next Proxy. Proxies not processed are passed upstream unchanged. Boers, et al. Expires August 5, 2005 [Page 4] Internet-Draft The PIM Proxy format february 2005 3. PIM Proxy packet format 3.1 PIM Join packet format There is no space in the default PIM source encoding to include a Proxy field. Therefore we introduce a new source encoding type. The proxies are formatted as TLV's. The new Encoded source address looks like this: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Addr Family | Encoding Type | TLV # |S|W|R| Mask Len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |F| Type | Length | Value +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+..... |F| Type | Length | Value +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+..... . . . . . . TLV # gives the number of TLV's that are included with this source. With the 5 bits we can include a maximum of 31 TLV's F bit, Forward Unknown TLV bit. If this bit is set the TLV is forwarded regardless if the router understands the Type. Type field of the TLV is 7 bits. Length field of the TLV is 1 byte. The other fields are the same as described in the PIM spec. [I-D.ietf-pim-sm-v2-new]. The source TLV encoding type: TBD. 3.2 PIM Proxy Hello option 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OptionType = XX | OptionLength = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Option type: TBD. Boers, et al. Expires August 5, 2005 [Page 5] Internet-Draft The PIM Proxy format february 2005 4. Acknowledgments The authors would like to thank James Lingard for his comments on this topic. 5. References 5.1 Normative References [I-D.ietf-pim-sm-v2-new] Fenner, B., Handley, M., Holbrook, H. and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode PIM-SM): Protocol Specification (Revised)", Internet-Draft draft-ietf-pim-sm-v2-new-11, October 2004. 5.2 Informative References Authors' Addresses Arjen Boers Cisco Systems, Inc. Avda. Diagonal, 682 Barcelona 08034 Spain Email: aboers@cisco.com IJsbrand Wijnands Cisco Systems, Inc. De kleetlaan 6a Diegem 1831 Belgium Email: ice@cisco.com Eric Rosen Cisco Systems, Inc. 1414 Massachusetts Avenue Boxborough, Ma 01719 Email: erosen@cisco.com Boers, et al. Expires August 5, 2005 [Page 6] Internet-Draft The PIM Proxy format february 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Boers, et al. Expires August 5, 2005 [Page 7]