Internet Engineering Task Force D. Zhou, Ed. Internet-Draft Hangzhou H3C Tech. Co., Ltd. Intended status: Informational H. Deng Expires: June 3, 2011 China Mobile Research Institute Y. Liu Hangzhou H3C Tech. Co., Ltd. H. Liu Huawei Technologies Co., Ltd. Y. Shi Hangzhou H3C Tech. Co., Ltd. I. Bhattacharya X. Xu Cisco Systems November 30, 2010 Source Network PIM Snooping draft-zhou-pim-source-network-pim-snooping-00 Abstract This document proposes a multicast stream prohibition method based on the switch between source and FHR (First Hop Router) snooping unicast PIM messages towards source which enables switch to prohibit unnecessary multicast stream towards FHR. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on June 3, 2011. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Zhou, et al. Expires June 3, 2011 [Page 1] Internet-Draft Source Network PIM Snooping November 2010 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. Zhou, et al. Expires June 3, 2011 [Page 2] Internet-Draft Source Network PIM Snooping November 2010 1. Introduction In many typical deployment scenarios, link layer switches running IGMP-Snooping which exist between multicast sources and PIM FHR have to forward all multicast streams to PIM FHR. This will lead to waste of switches' cache and link bandwidth. The problem has been discribed in detail in the draft of draft-dizhou-pim-umf-problem-statement. This document proposes a method for switch between source and FHR to snoop unicast PIM messages towards source which enables switch to prohibit unnecessary multicast stream towards FHR. Zhou, et al. Expires June 3, 2011 [Page 3] Internet-Draft Source Network PIM Snooping November 2010 2. Terminology In this document, several words are used to signify the requirements of the specification. These words are often capitalized. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119] With respect to PIM, this document follows the terminology that has been defined in RFC 4601 [RFC4601]. 2.1. Definitions Pruned port: A port of PIM-Snooping entry which stops forwarding multicast stream. Downstream port: A port of PIM-Snooping entry which forwards multicast stream. Upstream port: A port of PIM-Snooping entry which receives multicast source. Membership port: A port of IGMP-Snooping entry at which the switch receives IGMP Membership Report. Router port: A port of IGMP-Snooping entry at which the swtich receives IGMP Query or PIM massages. If a port has characters of Downstream port, Pruned port, Membership port simultaneously, the priority sequence is Membership port, Pruned port, Downstream port. Zhou, et al. Expires June 3, 2011 [Page 4] Internet-Draft Source Network PIM Snooping November 2010 3. Protocol Description The PIM snooping functionality is separated into two control sections (PIM forwarding and IGMP forwarding) and a data section (Data forwarding). 3.1. PIM Forwarding Rules When switch receives a PIM Hello, it will create pim neighbor list. When switch receives a Unicast PIM Prune, it will judge whether the PIM Prune is from the port at which there is a corresponding pim neighbor and whether the upstream neighbor address of the PIM Prune is in its pim neighbor list. If the former is yes and the latter is no, it will create a pruned port, at which the switch received the PIM Prune, for the PIM-Snooping (S,G) entry, as well as a upstream port which could be found by mac table. If the entry of (S,G) is created at first time, other ports where there are pim neighbors SHALL be added as downstream ports into the out-interface list of (S,G) entry. If the former is no, the PIM Prune shall be discarded. If the former is yes and the latter is yes, it shall be processed as traditional pim-snooping. If the PIM-Snooping (S,G) entry has no downstream port and other pruned ports and IGMP-Snooping entry has no membership port, switch shall forward the PIM Prune towards source. Otherwise the PIM Prune SHALL be discarded. Lifetime of Pruned port is 1/3 of that of (S,G) entry. After time out, the port would be changed to be a downstream port. This (S,G) entry SHALL be punched with a specific sign. When switch receives a Unicast PIM Join, it will judge whether the PIM Join is from the port at which there is a corresponding pim neighbor and whether the upstream neighbor address of the PIM Prune is in its pim neighbor list. If the former is yes and the latter is no, it will change the pruned port to be a downstream port, at which the switch received the PIM Join, for the (S,G) entry. If the former is no, the PIM Prune shall be discarded. If the former is yes and the latter is yes, it shall be processed as traditional pim-snooping. If the PIM-Snooping entry has no other downstream ports and IGMP- Snooping entry has no other membership ports, switch shall forward the PIM Join towards source. Otherwise the PIM Join SHALL be discarded. If (S,G) entry with the specific sign has no pruned ports, it SHALL Zhou, et al. Expires June 3, 2011 [Page 5] Internet-Draft Source Network PIM Snooping November 2010 be deleted. 3.2. IGMP Forwarding Rules For the IGMP Membership Report, switch SHALL forward it towards Upstream port and Downstream ports. 3.3. Data Forwarding Rules When there is no PIM-Snooping (S,G) entry, multicast stream of (S,G) SHALL be forwarded by swtich towards router ports and membership ports of IGMP-Snooping entry. If there is an PIM-Snooping entry of (S,G), switch SHALL forward multicast stream towards downstream ports and membership ports, but stop forwarding towards pruned ports. If a port has characters of Downstream port, Pruned port, Membership port simultaneously, the priority sequence is Membership port, Pruned port, Downstream port. The swtich SHALL treat the port as the most prior character. Zhou, et al. Expires June 3, 2011 [Page 6] Internet-Draft Source Network PIM Snooping November 2010 4. Other solutions If the UNICAST PIM Join message is replaced with IGMP Graft like message, and the UNICAST PIM Prune message is replaced with IGMP Prune like message, the mechanism above is also suitable. Zhou, et al. Expires June 3, 2011 [Page 7] Internet-Draft Source Network PIM Snooping November 2010 5. Security Considerations Zhou, et al. Expires June 3, 2011 [Page 8] Internet-Draft Source Network PIM Snooping November 2010 6. Contributors Zhou, et al. Expires June 3, 2011 [Page 9] Internet-Draft Source Network PIM Snooping November 2010 7. Acknowledgements Zhou, et al. Expires June 3, 2011 [Page 10] Internet-Draft Source Network PIM Snooping November 2010 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4541] Christensen, M., Kimball, K., and F. Solensky, "Considerations for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) Snooping Switches", RFC 4541, May 2006. [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006. Zhou, et al. Expires June 3, 2011 [Page 11] Internet-Draft Source Network PIM Snooping November 2010 Authors' Addresses Di Zhou (editor) Hangzhou H3C Tech. Co., Ltd. 310 Liuhe Road Hangzhou, Zhejiang China(310053) Phone: +86-571-86761327 Email: zhoudi@h3c.com Hui Deng China Mobile Research Institute Unit2,28 Xuanwumenxi Ave,Xuanwu District Beijing, Beijing China(100053) Phone: +86-010-15801696688-3314 Email: denghui@chinamobile.com Yu Liu Hangzhou H3C Tech. Co., Ltd. Beijing R&D Center of H3C, Digital Technology Plaza, NO.9 Shangdi 9th Street,Haidian District, Beijing China(100085) Phone: +86 010 82775153 Email: liuyu@h3c.com Hui Liu Huawei Technologies Co., Ltd. Huawei Bld., No.3 Xinxi Rd. Shang-Di Information Industry Base, Hai-Dian Distinct, Beijing China(100085) Email: helen.liu@huawei.com Zhou, et al. Expires June 3, 2011 [Page 12] Internet-Draft Source Network PIM Snooping November 2010 Yang Shi Hangzhou H3C Tech. Co., Ltd. Beijing R&D Center of H3C, Digital Technology Plaza, NO.9 Shangdi 9th Street,Haidian District, Beijing China(100085) Phone: +86 010 82775276 Email: young@h3c.com Indranil Bhattacharya Cisco Systems India(560037) Email: myselfindranil@gmail.com Xiaomin Xu Cisco Systems China(200051) Email: xiaomxu@cisco.com Zhou, et al. Expires June 3, 2011 [Page 13]