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    PIM Working Group                                         Hong-Ke Zhang
    Internet Draft                                                Shuai Gao
    Intended status: Standards Track            Beijing Jiaotong University
    Expires: September 10, 2013                                 T C.Schmidt
                                                                HAW Hamburg
                                                                Bo-hao Feng
                                                                 Li-Li Wang
                                                Beijing Jiaotong University
                                                             March 11, 2013
    
    
                     Multi-Upstream Interfaces IGMP/MLD Proxy
                           draft-zhang-pim-muiimp-00.txt
    
    
    
    
    
    Abstract
    
       In this document, followed by the idea mentioned in [4] and
       subsequent update in [5], an IGMP/MLD proxy with multiple upstream
       interfaces called MUIIMP is proposed and analyzed. The MUIIMP
       inherits the basic rule of the IGMP/MLD proxy but extends with
       multiple  upstream  interfaces.  To  avoid  data  redundancy,  each
       upstream interface of an MUIIMP device MUST NOT send or subscribe
       the same data simultaneously.
    
    
    
    Requirements Language
    
       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 [RFC2119].
    
    Status of this Memo
    
       This Internet-Draft is submitted to IETF in full conformance with
       the provisions of BCP 78 and BCP 79.
    
       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".
    
    
    
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     Internet-Draft  Multi-Upstream Interfaces IGMP/MLD Proxy     March 2013
    
    
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       Copyright (c) 2012 IETF Trust and the persons identified as the
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    Table of Contents
    
       1. Introduction..................................................3
       2. Terminology...................................................3
       3. MUIIMP Behavior...............................................4
        3.1. The selection of default upstream interface................5
        3.2. Report of downstream subscriptions to upstream interfaces..5
        3.3. Handover of the upstream interface.........................6
       4. Security Considerations.......................................6
       5. References....................................................6
       Acknowledgment...................................................8
    
    
    
    
    
    
    
    
    
    
    
    
    
    
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      1. Introduction
    
       RFC 4605 [1] specifies an IGMP/MLD proxy mechanism for forwarding
       based solely upon IGMP/MLD membership information in scenarios where
       multicast routing is not available. According to [1], an IGMP/MLD
       Proxy performs the router portion of the IGMP/MLD protocol on its
       downstream interfaces, and the host portion of the IGMP/MLD protocol
       on its single upstream interface.
    
       The IGMP/MLD proxy mechanism can effectively extend the multicast
       scope and greatly simplify the implementation of edge devices.
       However,  the  IGMP/MLD  proxy  may  exhibit  inefficiency  in  some
       specific  scenarios  due  to  the  limitation  of  single  upstream
       interface. For example, in PMIPv6 multicast environment, multiple
       IGMP/MLD proxy instances need to be deployed at the MAG in [6],
       which may result in tunnel convergence problem. In addition, there
       are also requirements to extend the IGMP/MLD proxy to support
       multiple upstream interfaces as the emergence of multi-homing.
    
       One thing to note is the idea about multiple upstream interfaces for
       IGMP/MLD proxy was firstly proposed in the draft [4] to improve the
       performance of mobile multicast source. The Multimob working group
       draft [5] includes the related latest descriptions. Considering the
       multiple upstream interfaces extension is not only required for
       mobile multicast sources scenarios, this document is presented here.
    
       In  this  document,  an  IGMP/MLD  proxy  with  multiple  upstream
       interfaces called MUIIMP is proposed and described. The MUIIMP
       inherits the basic rule of the IGMP/MLD proxy but extends with
       multiple  upstream  interfaces.  To  avoid  data  redundancy,  each
       upstream interfaces of an MUIIMP device MUST NOT send or subscribe
       the same data simultaneously. The MUIIMP is designed to support
       local multicast listeners and senders.
    
      2. Terminology
    
       Upstream Interface: A proxy device's interface in the direction of
       the root of the tree.
    
       Downstream Interface: Each of a proxy device's interfaces that is
       not in the direction of the root of the multicast tree.
    
       Default upstream interface: An upstream interface which is by
       default associated with each downstream node subscribing or sending
       specific channel (group address prefix) or special multicast state.
    
    
    
    
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      3. MUIIMP Behavior
    
       The MUIIMP inherits the basic rule of the IGMP/MLD proxy but extends
       with multiple upstream interfaces. A MUIIMP device has one or more
       upstream as well as downstream interfaces, which may be any type
       interfaces, including physical or logical interfaces.
    
       The MUIIMP performs the router portion of the IGMP/MLD protocol on
       its downstream interfaces, and the host portion of IGMP/MLD on its
       upstream interfaces.  The MUIIMP device MUST NOT perform the router
       portion of IGMP/MLD on its upstream interfaces.
    
       The MUIIMP device maintains a database for multicast listeners
       consisting of the merger of all subscriptions on any downstream
       interface. In order to avoid the redundant multicast traffic, the
       proxy device should initiate unique traffic subscriptions. Besides,
       a policy list that records the default upstream interface for the
       downstream nodes is held for the selection of upstream interface.
    
       In the following, the MUIIMP device behavior will be discussed
       according the role of the downstream nodes.
    
       1) Multicast listener on the downstream interface
    
       Multicast listener reports are group-wise aggregated by the MLD
       proxy. The aggregated report is issued to the upstream interface
       based on the subscriptions as well as the policy list. When
       receiving the IGMP/MLD subscriptions on the downstream interface,
       the MUIIMP checks the membership database to make a decision whether
       sends IGMP/MLD membership reports on the corresponding default
       upstream interface or not. Refer to Section 3.2 for the details
       about membership subscriptions lookup and report decisions.
    
       When receiving packets on its upstream interfaces, the MUIIMP
       forwards the traffic to all the downstream interfaces based upon the
       downstream interfaces' subscriptions.
    
       2) Multicast source on the downstream interface
    
       When receiving packets on its downstream interface, the MUIIMP
       forwards the traffic to the corresponding default upstream interface,
       as well as all the downstream interfaces other than the incoming
       interface based upon the downstream interfaces' subscriptions.
    
       The (first) multicast router(s) operating multicast routing protocol
       like PIM-SM[7]connected to the outside multicast domain should be
       configured to treat the multicast source inside the MUIIMP domain
    
    
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       being directly connected. Otherwise, it will discard the data due to
       the failure of the direct connection check.
    
       3.1. The selection of default upstream interface
    
       Typically, the choice of the default upstream interface is based on
       the policy list which is maintained at the MUIIMP.
    
       The expression of the policy list is like below:
    
       (node prefix, multicast group address/multicast state, upstream
       interface)
    
       Here node prefix represents the address prefix of the node on the
       downstream interface that may be a multicast listener or multicast
       source. And the multicast group address indicates the channel that
       the multicast listener is subscribing or the multicast source is
       publishing while the multicast state is only valid for listeners
       indicating the state about both multicast source and multicast group
       they are subscribing.
    
       In other word, in the MUIIMP, the multicast group address/multicast
       state and the node prefix will act as rules to select the default
       upstream interface. Alternate configurations (e.g., the MAG-LMA
       tunnel interface in PMIPv6 environment) MAY be applied.
    
       3.2. Report of downstream subscriptions to upstream interfaces
    
       To avoid the redundant multicast traffic, the proxy device MUST NOT
       send the same multicast subscription record on different upstream
       interfaces simultaneously. In detail, we recommend the following
       rules when receiving an IGMP/MLD subscription on the downstream
       interface.
    
       1) If the received IGMP/MLD subscription is new and has not been
          subscribed by other downstream multicast listeners, the proxy
          device  SHOULD  initiate  the  IGMP/MLD  subscription  on  the
          corresponding default upstream interface.
    
       2) If there exists the same IGMP/MLD subscription which has already
          been subscribed by other downstream multicast listener, the proxy
          device SHOULD not initiate extra IGMP/MLD subscription.
    
       3) If  there  exists  IGMP/MLD  subscriptions  which  have  already
          included the received IGMP/MLD subscription, the proxy device
          SHOULD not initiate extra IGMP/MLD subscription.
    
    
    
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       4) If there exists overlapping subsets between the received IGMP/MLD
          subscription and current IGMP/MLD subscriptions, the proxy device
          SHOULD initiate the IGMP/MLD subscription on the corresponding
          default upstream interface excluding the overlapping subsets that
          have been subscribed before.
    
       All subscriptions sent on the same upstream interface SHOULD be
       merged according the merging rule in RFC 4605. In addition, the
       local multicast source should be excluded in the final subscriptions
       to avoid replicated multicast traffic from outside.
    
       3.3. Handover of the upstream interface
    
       If an upstream interface fails for some reason such as the deletion
       of the tunnel interface in mobile environment, the handover of the
       upstream interface is performed. Generally, all the subscriptions
       sent on the previous invalid upstream interface are transferred to
       the new valid upstream interfaces which are chosen among the default
       upstream interfaces of the corresponding downstream nodes. The
       choice may be made based on the predefined policy (e.g., the
       interface priority, the number of listeners, the lowest IP address).
       An alternative may be applied by the MUIIMP device itself according
       to the traffic monitored or some strategies configured by the
       operator.
    
    
    
      4. Security Considerations
    
       To be done.
    
    
    
      5. References
    
       [1]  B. Fenner, H. He, B. Haberman and H. Sandick. "Internet Group
             Management Protocol (IGMP) / Multicast Listener Discovery
             (MLD)-Based Multicast Forwarding ("IGMP/MLD Proxying")", RFC
             4605, August 2006.
    
       [2]  Cain, B., Deering, S., Kouvelas, I., Fenner, B. and A.
             Thyagarajan, "Internet Group Management Protocol, Version3",
             RFC 3376, October 2002.
    
       [3]  Vida, R. and L. Costa, "Multicast Listener DiscoveryVersion 2
             (MLDv2) for IPv6", RFC 3810, June 2004.
    
    
    
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       [4]  Hong-Ke Zhang, Zhi-Wei Yan, Shuai Gao, etal.,"Multicast Source
             Mobility Support in PMIPv6 Network", draft-zhang-multimob-msm-
             03, July 2011.
    
       [5]  T C. Schmidt, S. Gao, H. Zhang, M. Waehlisch,"Mobile Multicast
             Sender Support in Proxy Mobile IPv6 (PMIPv6) Domains", draft-
             ietf-multimob-pmipv6-source-02, October2012.
    
       [6]  T. Schmidt, M. Waehlisch and S. Krishnan. "Base Deployment
             forMulticast Listener Support in Proxy Mobile IPv6 (PMIPv6)
             Domains", RFC 6224, April 2011.
    
       [7]  Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
             "Protocol  Independent  Multicast  -  Sparse  Mode  (PIM-SM):
             Protocol Specification (Revised)", RFC 4601, August 2000.
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
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    Authors' Addresses
    
       Hong-Ke Zhang, Shuai-Gao, Bo-Hao Feng, Li-Li Wang
       National Engineering Lab for NGI Interconnection Devices
       Beijing Jiaotong University, China
    
       Phone: +861051684274
       Email:hkzhang@bjtu.edu.cn
             shgao@bjtu.edu.cn
             11111021@bjtu.edu.cn
             liliwang@bjtu.edu.cn
    
       Thomas C. Schmidt
       HAW Hamburg
       Berliner Tor 7
       Hamburg  20099
       Germany
    
       Email: schmidt@informatik.haw-hamburg.de
       URI:   http://inet.cpt.haw-hamburg.de/members/schmidt
    
    
    
    
    Acknowledgment
    
       Funding for the RFC Editor function is currently provided by the
       Internet Society.
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
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