Internet DRAFT - draft-jiang-v6ops-v4v6mc-proxy

draft-jiang-v6ops-v4v6mc-proxy



v6ops Work Group                                              S. Jiang 
Internet Draft                                                   D. Gu 
Intended status: Informational                                   Y. Fu 
Expires: April 21, 2013                                         B. Liu 
                                          Huawei Technologies Co., Ltd 
                                                      October 22, 2012 
                                    
                Multicast Proxy in IPv6/IPv4 Transition 
                   draft-jiang-v6ops-v4v6mc-proxy-02 


Status of this Memo 

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   This Internet-Draft will expire on April 21, 2013. 

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Abstract 

   During the long co-existing period of IPv6 and IPv4, the 
   interoperation between IPv6 network and IPv4 network is essential. 
   Multicast services across IPv6 and IPv4 networks are also needed. 
   Besides the packet-based multicast translation mechanism, this 
   document describes a multicast proxy solution. The solution is a 
   multicast deployment for transition scenario. It does not propose  
   any new protocol or protocol modification/extension for multicast. 
   The multicast proxy is deployed at the border of IPv6/IPv4 networks. 
   It is mainly based on content  
   cache. Without packet-based translation, it acquires the content data 
   from IPvX network, caches the data, and multicasts the data in IPvY 
   network. It acts as a multicast leaf in the IPvX network where the 
   data source locates while acting as a multicast source in IPvY 
   network where the multicast client locates. 

Table of Contents 

   1. Introduction ................................................ 3 
   2. Terminology ................................................. 3 
   3. Multicast Proxy without packet-based IPv6/IPv4 Translation .. 3 
      3.1. Overview ............................................... 3 
      3.2. Operation procedure .................................... 5 
   4. Security Considerations ..................................... 6 
   5. IANA Considerations ......................................... 7 
   6. Acknowledgments ............................................. 7 
   7. References .................................................. 7 
      7.1. Normative References ................................... 7 
      7.2. Informative References ................................. 7 
   Author's Addresses ............................................. 8 
    












 
 
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1. Introduction 

   The deployment of IPv6 is now in progress, and users with 
   no IPv4 access are likely to appear in increasing numbers in the 
   coming years. However, it is also widely agreed that IPv4 will be 
   still in use for a long period. During the long co-existing period of 
   IPv6 and IPv4, the interoperation between IPv6 network and IPv4 
   network is essential.  

   Now, multimedia has been deployed widely, such as IPTV and video 
   conference etc. They also face the IPv6 and IPv4 intercommunication 
   issues. The multicast applications are complicated and face more 
   difficulties than unicast applications deployment. 

   [I-D.draft-venaas-behave-v4v6mc-framework] proposes a packet-based 
   translation framework between IPv4/IPv6 multicast services. It 
   describes the packet-based translation operations and 
   intercommunication in network layer to support a single source send 
   to multiple receivers in different IP networks. 

   Besides the packet-based multicast translation mechanism, this 
   document describes a multicast proxy solution, which is mainly based 
   on content cache. It is a multicast deployment for IPv6 transition 
   scenario. It doesn't propose any new protocol or protocol 
   modification/extension for multicast. 

   A multicast proxy can be deployed at the border between IPv4/IPv6 
   networks. Without packet-based translation, it acquires the content 
   data from IPvX network, caches the data, and multicasts the data in 
   IPvY network. It acts as a multicast leaf in the IPvX network where 
   the data source locates while acting as a multicast source in IPvY 
   network where the multicast client locates. 

2. Terminology 

   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 [RFC2119]. 

3. Multicast Proxy without packet-based IPv6/IPv4 Translation 

3.1. Overview 

   Within this document, we describe the network where the data source 
   locates as IPvX network and the network where the multicast client 

 
 
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   locates as IPvY network. When IPvX is IPv6, IPvY must be IPv4, vice 
   versa. 

                                | 
      <----------IPvX---------->|<---------IPvY-----------> 
                                | 
      +-----------+       +-----------+       +-----------+ 
      | multicast |------>| multicast |------>| multicast | 
      |  source   |       |   proxy   |       |   client  | 
      +-----------+       +-----------+       +-----------+ 
                                | 
   Figure 1: Multicast proxy Forwards Contents to different IP networks 

   As showed in Figure 1, the proposed multicast proxy is deployed at 
   the border of IPv4/IPv6 networks. It MUST support both IPv4 and IPv6. 
   It MUST support both IGMP (Internet Group Management Protocol, 
   [RFC3376]), which is used for IPv4 multicast management functions, 
   and MLD (Multicast Listener Discovery, [RFC3810]), which is used in a 
   similar way in IPv6 Environment. In the IPvX network, the multicast 
   proxy joins the multicast distribution tree as a leaf. In the IPvY 
   network, the multicast proxy broadcasts contents as a multicast 
   source. The establishment of multicast distribution trees obeys the 
   current multicast specifications for each IP family, such as Protocol 
   Independent Multicast (PIM [RFC4601]). 

   Notice that there are two different multicast distribution trees in 
   two sides of the multicast proxy. They are operational independent 
   from each other in the network layer. 

   Logically, they are relevant to each other and there are 
   interoperation behaviors between them. The contents published through 
   the multicast distribution tree in IPvY network inherits from the 
   IPvX network. They are received by the multicast proxy, which is a 
   multicast leaf in the multicast distribution tree in IPvX network. 
   Within the multicast proxy, contents are mapped between receiver 
   function and publisher function. The operations of the multicast 
   distribution tree in IPvY network MAY trigger some operations of the 
   multicast distribution tree in IPvX network. For example, a multicast 
   client joins a multicast group in IPvY network, and requests 
   multicast contents may cause the multicast proxy joins a multicast 
   group in IPvX network. 

   However, as mentioned earlier, in network or IP layer, the two 
   multicast distribution trees are independent from each other. Their 
   operations are separated in two sides of the multicast proxy. 
   Conceptually, the multicast proxy can be presented virtually in 
   functional modules like below Figure 2. 
 
 
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   <------------IPvX-------------->|<------------IPvY---------------> 
                   +-------------------------------+ 
                   |     +-------------------+     | 
                   |     |Content cache & mgt|     | 
                   |     +-------------------+     | 
                   |       /                \      | 
   +---------+     | +----------+     +----------+ |     +---------+ 
   |multicast|     | |  proxy   |     |  proxy   | |     |multicast| 
   | source  |-----+>| receiver |     | publisher|-+---->|  client | 
   |         |     | |  (IPvX)  |     |  (IPvY)  | |     |         | 
   +---------+     | +----------+     +----------+ |     +---------+ 
                   +-------------------------------+ 
                                   | 
          Figure 2: Separate function model of multicast proxy 

   As shown in Figure 2, the proxy receiver module in IPvX network joins 
   IPvX multicast groups as a receiver client. Thereby it receives 
   packets bound for the IPvX multicast groups, and then hands the 
   content to the content cache and management module. The content cache 
   and management module then forward the on-demand content to the 
   multicast proxy function module in IPvY network, which acts as a 
   publisher and multicast source in IPvY network. 

3.2. Operation procedure 

   <-------------IPvX---------------->|<------------IPvY---------------> 
   multicast source            multicast proxy          multicast client 
      |                      Content cache & mgt                      | 
      |          proxy receiver       |     proxy publisher           | 
      |               |               |               |               | 
      |               |               |               |   Join IPvY   | 
      |               |               |               |multicast group| 
      |               |               | Report to mgt |<-----(1)------| 
      |               |  Send request |<-----(2)------|               | 
      |Join IPvX group|<-----(3)------|               |               | 
      |<-----(4)------|               |               |               | 
      |               |               |               |               | 
      |   Send IPvX   |               |               |               | 
      |multicastpacket|               |               |               | 
      |------(5)----->|Report contents|Divert request&|               | 
      |               |------(6)----->|Divert contents|   Send IPvY   | 
      |               |               |------(7)----->|multicastpacket| 
      |               |               |               |------(8)----->| 
      |               |               |               |               | 

       Figure. 3 The interaction communicating from IPvX to IPvY 

 
 
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   As shown in Figure 3, a client, which locates in IPvY network, 
   connects to the multicast proxy, requesting a multicast service whose 
   source locates in the IPvX network. 

   First, the client sends a join IPvY multicast group report (1) to the 
   multicast proxy. The proxy publisher module, which also locates in 
   the IPvY network, receives this report, then forwards the content 
   request to the content cache & management module (2). The content 
   cache & mgt module maintains a content & multicast service table, 
   including all available multicast services from IPvX network. The 
   content cache & mgt module searches the client request in its 
   dynamically updated table. 

   If the requested content is already multicasted in the IPvY network, 
   the content cache & mgt module diverts the user report back to the 
   proxy publisher module (7). The proxy publisher module adds the new 
   client into its existing multicast tree. Then the requested content 
   can be sent to the client (8). 

   If the requested content is available but not multicasted in IPvY 
   network yet, the content cache & mgt module sends a request to the 
   proxy receiver module, which locates in the IPvX network (3). It 
   initiates the proxy receiver module to send a join IPvX multicast 
   group report (4) to the multicast source. The multicast source adds 
   the multicast proxy into its multicast tree and sends IPvX multicast 
   packets (5). After receiving the multicast packets, the proxy 
   receiver module extracts the contents while dropping all network 
   layer information, such as IP headers, etc. It then imports the 
   contents to the content cache & mgt module (6). The content cache & 
   mgt module then diverts contents to the correspondent channel of the 
   proxy publisher module (7). The proxy publisher module builds up a 
   new multicast tree in the IPvY network, and sends multicast packets 
   to clients (8). 

   If all the clients, requesting a certain multicast service in the 
   IPvY network, leave the IPvY multicast group, the multicast proxy MAY 
   leave the IPvX multicast group in IPvX network. 

   Multicast proxies MAY also perform load-balancing, user 
   authentication and other additional functions. 

4. Security Considerations 

   The multicast proxy solution actually separate the IPv4 and IPv6 
   multicast services effectively. It prevents the attacks at only one 
   side of it. 

 
 
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   However, multicast proxy itself is as vulnerable as normal multicast 
   sources and multicast leafs in each IPv4 or IPv6 environment. The 
   security mechanisms for IGMP/MLD can be used to enhance the security 
   of multicast proxy. 

5. IANA Considerations 

   This draft does not request any IANA action. 

6. Acknowledgments 

   The authors would like to thank Stig Venaas for his valuable
   comments. 

7. References 

7.1. Normative References 

   [RFC2119] S. Bradner, "Key words for use in RFCs to Indicate 
             Requirement Levels", BCP 14, RFC 2119, March 1997. 

   [RFC3376] B. Cain, S. Deering, I. Kouvelas, B. Fenner and A. 
             Thyagarajan, "Internet Group Management Protocol, Version 
             3", RFC 3376, October 2002. 

   [RFC3810] R. Vida and L. Costa, "Multicast Listener Discovery 2 
             (MLDv2) for IPv6", RFC 3810, June 2004. 

   [RFC4601] B. Fenner, M. Handley, H. Holbrook and I. Kouvelas, 
             "Protocol Independent Multicast - Sparse Mode (PIM-SM): 
             Specification (Revised)", RFC 4601, August 2006. 

7.2. Informative References 

   [I-D.draft-venaas-behave-v4v6mc-framework] 
             S. Venaas, X. Li and C. Bao, "Framework for IPv4/IPv6 
             Multicast Translation ", draft-venaas-behave-v4v6mc-
             framework, working in progress, June 2011. 








 
 
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Author's Addresses 

   Sheng Jiang 
   Huawei Technologies Co., Ltd 
   156 Bei-Qing Road, Hai-Dian District, Beijing 100095  
   P.R. China 
   Email: jiangsheng@huawei.com 
    
   Dujuan Gu 
   Huawei Technologies Co., Ltd 
   156 Bei-Qing Road, Hai-Dian District, Beijing 100095 
   P.R. China 
   Email: gudujuan@huawei.com 
    
   Yu Fu 
   Huawei Technologies Co., Ltd 
   156 Bei-Qing Road, Hai-Dian District, Beijing 100095 
   P.R. China 
   Email: eleven.fuyu@huawei.com 
    
   Bing Liu 
   Huawei Technologies Co., Ltd 
   156 Bei-Qing Road, Hai-Dian District, Beijing 100095 
   P.R. China 
   Email: leo.liubing@huawei.com 
    




















 
 
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