Network Working Group B. Sarikaya Internet-Draft Huawei USA Intended status: Standards Track October 11, 2011 Expires: April 13, 2012 Multicast Support for 6rd draft-sarikaya-softwire-6rdmulticast-02.txt Abstract This memo specifies modifications required to 6rd so that both IPv6 hosts can receive multicast data from IPv6 servers. In AMT based solution, AMT Gateway at the 6rd Customer Edge router uses AMT protocol to establish a tunnel interface with AMT Relay at the 6rd Border Relay and this tunnel is used to exchange MLD messages to establish multicast state at AMT Relay so that AMT Relay can tunnel IPv6 multicast data to IPv6 hosts connected to AMT Gateway. In 6rd Proxy Multicast solution, the protocol is based on proxying MLD at the 6rd Customer Edge router and then tunneling MLD messages to 6rd Border Relays where IPv6 multicast routing is supported. Multicast data received at 6rd Border Relay is tunneled to 6rd Customer Edge node and then delivered to the hosts. We show that IPv4 multicast and IGMP can be supported in a similar way. 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 April 13, 2012. 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 Sarikaya Expires April 13, 2012 [Page 1] Internet-Draft Multicast Support for 6rd October 2011 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 4 4.1. AMT Architecture . . . . . . . . . . . . . . . . . . . . . 5 4.2. Proxy Architecture . . . . . . . . . . . . . . . . . . . . 6 5. 6rd AMT Multicast Operation . . . . . . . . . . . . . . . . . 7 5.1. Modifications to AMT Messages . . . . . . . . . . . . . . 8 5.2. Supporting IPv4 Multicast in 6rd AMT Multicast . . . . . . 9 6. 6rd Proxy Multicast Operation . . . . . . . . . . . . . . . . 10 6.1. Tunnel Interface Considerations . . . . . . . . . . . . . 11 6.2. Supporting IPv4 Multicast in 6rd Proxy Multicast . . . . . 11 7. Solution Based on Layer 2 Multicast Support . . . . . . . . . 12 8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 11.1. Normative References . . . . . . . . . . . . . . . . . . . 13 11.2. Informative references . . . . . . . . . . . . . . . . . . 14 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15 Sarikaya Expires April 13, 2012 [Page 2] Internet-Draft Multicast Support for 6rd October 2011 1. Introduction With IPv4 address depletion on the horizon, many techniques are being standardized for IPv6 migration including 6rd [RFC5969]. 6rd enables IPv6 hosts to communicate with external hosts using IPv4 only legacy ISP network. 6rd Customer Edge (CE) device's LAN side is dual stack and WAN side is IPv4 only. CE tunnels IPv6 packets received from the LAN side to 6rd Border Relays (BR) after encapsulating IPv6 packet in an IPv4 packet. BRs have anycast IPv4 addresses and receive encapsulated packets from CEs over a virtual interface. 6rd operation is stateless. Packets are received/ sent independent of each other and no state needs to be maintained. 6rd as defined in [RFC5969] and [RFC5569] is unicast only. It does not support multicast. In this document we specify how multicast from home IPv6 users can be supported in 6rd. We also show how IPv4 multicast can be supported for home IPv4 users. Both solutions use IPv6 and IPv4 multicast addressing and do not require any new multicast address prefixes such as IPv4-embedded IPv6 multicast addresses to be allocated. Automatic IP Multicast Tunneling (AMT) enables the host(s) in an AMT site to connect to an AMT Relay which is a multicast router in the multicast infrastructure [I-D.ietf-mboned-auto-multicast]. The network between an AMT site and Relay is not multicast enabled and is seen as non-broadcast multi-access (NBMA) link layer [RFC2491]. When an AMT gateway receives an MLD join message to an Any-Source Multicast (ASM) or Source-Specific Multicast (SSM) group, it first discovers an AMT Relay using Anycast Relay IP address. Using a three way handshake the gateway sends MLD membership report message in a UDP tunnel to the relay. Relay joins the source in the multicast infrastructure and sends multicast data downstream to all member gateways in a UDP tunnel. When a gateway has no membership state, i.e. after all member hosts leave the group(s), its state with the relay expires and the gateway can start relay discovery all over again. Periodically the relay and gateway exchage AMT Query and AMT Membership Update messages. All AMT control messages are secured using message authentication codes (MAC). AMT works for both IPv4 using IGMP and IPv6 using MLD. IGMP messages are encapsulated in IPv4 using UDP encapsulation and MLD messages are encapsulated in IPv6 using UDP encapsulation. In this document we address 6rd multicast problem and propose two architectures: Automatic IP Multicast tunneling (AMT) and MLD Proxy based solutions. Solution based on Layer 2 multicast support is also described for 6rd. Sarikaya Expires April 13, 2012 [Page 3] Internet-Draft Multicast Support for 6rd October 2011 2. Terminology This document uses the terminology defined in [RFC5969], [RFC5569], [RFC3810] and [RFC3376]. 3. Requirements This section states requirements on 6rd multicast support protocol. IPv6 hosts connected to 6rd CE router MUST be able to join multicast groups in IPv6 and receive multicast data. Both any source multicast (ASM) and source specific multicast (SSM) MUST be supported. 6rd CE MAY support AMT gateway as defined in [I-D.ietf-mboned-auto-multicast]. Modifications to AMT protocol defined in this document applies. 6rd BR MAY support AMT relay as defined in [I-D.ietf-mboned-auto-multicast]. Modifications to AMT protocol defined in this document applies. In case of proxy solution, 6rd CE MUST support MLD Proxy as defined in [RFC4605]. 6rd CE MAY support IGMP Proxy. In case of proxy solution, 6rd BR MUST support MLD Querier. 6rd CE MAY support IGMP Querier. 4. Architecture In 6rd, there are hosts (possibly IPv4/ IPv6 dual stack) served by 6rd Customer Edge device. CE is dual stack facing the hosts and IPv4 only facing the network or WAN side. At the boundary of the network there is 6rd Border Relay. BR receives IPv6 packets tunneled in IPv4 from CE and decapsulates them and sends them out to IPv6 network. Unicast 6rd is stateless. Each IPv6 packet sent by CE treated separately and different packets from the same CE may go to different BRs. CE encapsulates IPv6 packet in IPv4 with destination address set to BR address (usually anycast IPv4 address). BRs are placed where IPv6 native connectivity exists. BR receives the encapsulated packet and decapsulates and send it to IPv6 network. CEs are configured with 6rd Prefixes from ISPs prefix and with a number of BR IPv4 addresses. Each host is given a prefix which contains 6rd Prefix and the host's IPv4 prefix. BR receives IPv6 packets Sarikaya Expires April 13, 2012 [Page 4] Internet-Draft Multicast Support for 6rd October 2011 addressed to this ISP and from the destination address it extracts the destination host's IPv4 address and uses this address as destination address and encapsulates the IPv6 packet in IPv4 and sends it to IPv4-only network. 6rd considers IPv4-only network as an NBMA link from IPv6 point of view and all 6rd CEs and BRs are defined as off-link neighbors from one other. 4.1. AMT Architecture 6rd network lends itself easily to the automatic IP Multicast Tunneling architecture. Dual stack hosts connected to the Customer Edge router is an AMT site and it is multicast enabled. IPv4 only network is the unicast only network. At the boundary of the network 6rd Border Relay is connected to the native multicast backbone infrastructure. We place AMT Gateway at the CE router instead of at the hosts. CE router serves all the connected hosts. For multicast traffic, CE Router has an AMT pseudo-interface that serves as a default multicast route. It is a tunneling interface. AMT Relay is placed at 6rd BR. AMT Relay also has a pseudo- interface. A given relay and all CEs (AMT Gateways) connected to it can be considered to be on a separate logical NBMA link. On this link, gateways and relay communicate using AMT protocol to transmit and receive multicast control messages for membership management and multicast data from the relay to the gateways. All the elements of 6rd multicast support system with AMT are shown in Figure 1. AMT protocol is designed to provide IPv6 multicast to the hosts in AMT site using AMT messages in IPv6. AMT protocol is designed to provide IPv4 multicast to the hosts in AMT site using AMT messages in IPv4. However, in 6rd the network is IPv4 only. We need to modify it to use IPv4 AMT protocol to transmit IPv6 multicast messages such as MLD messages and IPv6 multicast data. Sarikaya Expires April 13, 2012 [Page 5] Internet-Draft Multicast Support for 6rd October 2011 Dual Stack Hosts IPv4 +----+ Network | H1 | IPv4 +----+ +-------+ only +-----+ + +----+ | CE | network | BR | | H2 | ---| AMT |--- -- | AMT | IPv6 +----+ |Gateway| |Relay| Network +----+ +-------+ +-----+ | H3 | +----+ Figure 1: Architecture of 6rd AMT Multicast 4.2. Proxy Architecture In order to support multicast, CE implements MLD Proxy function [RFC4605]. IPv6 hosts send their join requests (MLD Membership Report messages) to CE. CE as a proxy sends aggregated Report messages upstream towards BR. In order to support SSM, MLDv2 must be supported by the host, CE and BR. BR is the default multicast querier for CE. BR implements multicast router function or it could be another MLD proxy. All the elements of 6rd proxy-based multicast support system are shown in Figure 2. Dual Stack Hosts IPv4 +----+ Network | H1 | IPv4 +----+ +-----+ only +-------+ + +----+ | CE | network | BR | | H2 | ---| MLD |--- -- | MLD | IPv6 +----+ |Proxy| |Querier| Network +----+ +-----+ +-------+ | H3 | +----+ Figure 2: Architecture of 6rd Proxy Multicast Sarikaya Expires April 13, 2012 [Page 6] Internet-Draft Multicast Support for 6rd October 2011 5. 6rd AMT Multicast Operation When a host (H1, H2 or H3 in Figure 1) wants to join an IPv6 multicast group, it sends an MLD report (MLDv2 report for a source- specific group) to CE router. CE router uses one of 6rdBRIPv4Address values (anycast address of BR) this CE router is configured with. CE sends AMT Relay Discovery IPv4 message which is a UDP message sent to a IANA reserved AMT port, e.g. 2268. In the payload of this message CE MUST set the M bit to indicate that CE will encapsulate MLD messages in IPv4. Note that all UMT messages are UDP messages. BR (topologically closest to this CE router) receives the message and replies with AMT Relay Advertisement UDP message in IPv4. BR checks to see if it can provide IPv6 multicast service and if yes it replies with AMT Relay Advertisement message. BR MUST set the M bit to indicate that it can provide IPv6 multicast service. CE receives AMT Relay Advertisement message. CE now has BR's unicast address which it uses to send all multicast packets for this session. CE sends AMT Request message to BR's unicast address to begin the process of joining IPv6 multicast group. CE initializes a timer used to send periodic requests. BR sends AMT Query message. In this message an MLD Listener Query message is encapsulated [I-D.ietf-mboned-auto-multicast] with an IP header. CE receives AMT Query message and responds by sending AMT Membership Update message. This message encapsulates MLD Membership Report message with an IP header to request BR to join IPv6 multicast group the host wants to join. BR receives AMT Membership Update message and it adds the tunnel to the CE in its outgoing interface list for the group that the host wants to join. BR will send a join message towards the source of the multicast group to build a multicast tree in the native multicast infrastructure. After the initial three way handshake, periodically AMT Membership Query and AMT Membership Update messages are exchanged between BR and CE. As for multicast data, the data packets from the source received at BR will be replicated to all interfaces in it's outgoing interface list as well as the tunnel outgoing interface for all member CEs. BR sends multicast data in AMT Multicast Data messages to CE with the data packet encapsulated in UDP packet with IP header. CE receives AMT Multicast Data message over the pseudo interface Sarikaya Expires April 13, 2012 [Page 7] Internet-Draft Multicast Support for 6rd October 2011 associated with the tunnel to BR. CE forwards the packet to the outgoing interfaces joined by the hosts. Another host wants to join another IPv6 multicast group, three-way handshake involving AMT Request/ AMT Membership Query and AMT Membership Update is needed but AMT Relay Discovery/ AMT Relay Advertisement messages are not needed. 5.1. Modifications to AMT Messages This specification uses AMT messages as defined in [I-D.ietf-mboned-auto-multicast] except the changes stated in this section. AMT Relay Discovery message changes include the addition of two flags, M and I flags. AMT gateway uses these flags to negotiate MLD (IGMP) message transmission in IPv4 (IPv6). A summary of the AMT Relay Discovery message format is shown below. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=0x1 |M|I| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Discovery Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The type of the message M Flag Set to 1 if AMT Gateway wants to send MLD messages encapsulated in IPv4 I Flag Set to 1 if AMT Gateway wants to send IGMP messages encapsulated in IPv6 Reserved A 22-bit reserved field. Sent as 0, ignored on receipt. Discovery Nonce A 32-bit random value generated by the gateway and replayed by the relay. AMT Relay Advertisement message changes include the addition of two Sarikaya Expires April 13, 2012 [Page 8] Internet-Draft Multicast Support for 6rd October 2011 flags, M and I flags. AMT relay uses these flags to let AMT Gateway know if AMT Relay is capable of MLD (IGMP) message transmission in IPv4 (IPv6). A summary of the AMT Relay Advertisement message format is shown below. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type=0x2 |M|I| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Discovery Nonce | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Relay Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type The type of the message M Flag Set to 1 if AMT Gateway wants to send MLD messages encapsulated in IPv4 I Flag Set to 1 if AMT Gateway wants to send IGMP messages encapsulated in IPv6 Reserved A 22-bit reserved field. Sent as 0, ignored on receipt. Discovery Nonce A 32-bit random value generated by the gateway and replayed by the relay. Relay Address The unicast IPv4 address of the AMT relay. 5.2. Supporting IPv4 Multicast in 6rd AMT Multicast IPv4 multicast can be supported in a way similar to IPv6 using AMT architecture as described in Section 5. 6rd Customer Edge device has AMT Gateway function as described in [I-D.ietf-mboned-auto-multicast] with no extensions. IPv4 hosts connected to AMT Gateway send and receive IGMP messages [RFC3376] to AMT Gateway which uses AMT protocol to subscribe the multicast groups with AMT Relay at 6rd Border Relay. AMT Relay sends IPv4 multicast data in UDP Sarikaya Expires April 13, 2012 [Page 9] Internet-Draft Multicast Support for 6rd October 2011 encapsulated IPv4 messages to AMT Gateway. 6. 6rd Proxy Multicast Operation In this section we specify how the host can subscribe and receive IPv6 multicast data from IPv6 content providers based on the architecture defined in Figure 2. The hosts will send their subscription requests for IPv6 multicast groups upstream to the default router, i.e. Costumer Edge device. After subscribing the group, the host can receive multicast data from the CE. The host implements MLD protocol's host part. Customer Edge device is MLD Proxy. After receiving the first MLD Report message requesting subscription to an IPv6 multicast group, CE establishes a tunnel interface with a Border Relay. CE encapsulates MLD Membership Report message in IPv6-in-IPv4 tunnel and sends IPv4 message to BR's IPv4 anycast address, 6rdBRIPv4Address [RFC5969]. The tunnel is IPv4 based but it will carry IPv6 traffic, MLD messages back and forth and IPv6 multicast data messages downstream. CE gets unicast IPv4 address of BR from the first reply containing MLD message encapsulated in IPv4 and thereafter uses the BR unicast address as long as any multicast state exists. 6rd CE operation is similar to [RFC6224] but the operation is much simpler. In 6rd environment there is no requirement to handle host mobility. CE does not have to keep more than one tunnel interfaces, a single interface is sufficient. MLD Proxy at the CE does not have to have more than one proxy instances, a single instance is sufficient. CE is regular MLD proxy and it keeps MLD proxy membership database. CE inserts multicast forwarding state on the incoming interface, and merges state updates into the MLD proxy membership database. CE updates or removes elements from the database as required. CE will then send an aggregated Report via the upstream tunnel to the BR when the membership database changes. CE answers MLD queries from BR based on the membership database. CE's downstream link follows the traditional multipoint channel forwarding and does not pose any specific problems. CE receives IPv6 multicast data from the BR tunneled over the tunnel interface. CE decapsulates the packet and then forwards it downstream. Each member host receives the data packet based on Layer 2 multicast interface. No packet duplication is necessary. Sarikaya Expires April 13, 2012 [Page 10] Internet-Draft Multicast Support for 6rd October 2011 Border Relay acts as the as the default multicast querier for all CEs that have established an IPv4 tunnel with it. In order to keep a consistent multicast state between a CE and BR, once a CE is connected it will stay connected until the state becomes empty. After that point, the CE may establish another tunnel to a different BR. According to aggregated MLD reports received from a CE, BR establishes group/source-specific multicast forwarding states at its corresponding downstream tunnel interfaces. After that, BR maintains or removes the state as required by the aggregated reports received from CE. At the upstream interface, BR procures for aggregated multicast membership maintenance. Based on the multicast-transparent operations of the CEs, the BR treats its tunnel interfaces as multicast enabled downstream links, serving zero to many listening nodes. Multicast traffic arriving at the BR is transparently forwarded according to its multicast forwarding information base. Multicast data is first replicated and then forwarded in IPv6-in-IPv4 tunnel from BR to the corresponding CE. 6.1. Tunnel Interface Considerations IPv6 in IPv4 tunneling is performed as specified in [RFC4213]. Considerations specified in [RFC5969] apply. Packets upstream from CE carry only MLD signaling messages and they are not expected to be subject to fragmentation. However packets downstream, i.e. multicast data to CE may be subject to fragmentation. 6.2. Supporting IPv4 Multicast in 6rd Proxy Multicast IPv4 multicast can be supported in a way similar to IPv6 as described in Section 6. 6rd Customer Edge device has IGMP Proxy function. Proxy operation for IGMP [RFC3376] is described in [RFC4605]. CE receives IGMP join requests from the hosts and then sends aggregated IGMP Report messages upstream in an IPv4 in IPv4 tunnel. Tunnel addressing is in IPv4 and is as described in [RFC5969]. Multicast membership database is maintained for all active IPv4 multicast groups the hosts subscribe. 6rd Border Relay is IGMP querier or another IGMP Proxy. It serves all CEs downstream and treats its tunnel interfaces as multicast enabled downstream links, serving zero to many listening nodes. Multicast membership database is maintained based on the aggregated Sarikaya Expires April 13, 2012 [Page 11] Internet-Draft Multicast Support for 6rd October 2011 Reports received from downstream tunnel interfaces. IPv4 multicast data received from the multicast Single Source Multicast or Any Source Multicast sources are replicated according to the multicast membership database and the data packets are tunneled to the CEs that have one of more members of this multicast group. CEs receive multicast data upstream in the CE-BR tunnel and decapsulate it and then forward the packet downstream. Each member host receive IPv4 multicast data packet from its Layer 2 interface. 7. Solution Based on Layer 2 Multicast Support In this section we assume that Layer 2 multicast is supported in the network. Layer 2 multicast support is done in order to forward multicast data downstream to the ports of Layer 2 devices, i.e. switches that requested a multicast group instead of flooding the data to all the ports. In the switches called snooping switches, multicast MAC address based filters are setup which link Layer 2 multicast groups to the egress ports. When an MLD Report message is received, the bridge will setup a multicast filter entry that allows (in case of a join message) or prevents (in case of a leave message) packets to flow the port on which the MLD Report message was received. In terms of IP multicast addresses, the mapping is not unique as 2 ** (112 - 32) IPv6 multicast addresses map to a single Ethernet multicast MAC address. This would be reduced to 32 if allocation policy of using only the lower 32 bits in 112 bit group ID field of IPv6 multicast address is followed. Snooping switches maintain a list of multicast routers and the ports on which they are attached called router ports. For this purpose multicast router discovery protocol described in [RFC4286] is used. The switch sends an ICMPv6 Multicast Router Solicitation message and the router sends ICMPv6 Multicast Router Advertisement message in reply. The main functionality of a snooping switch is to forward multicast data packets based on the filters that are setup, i.e. to those egress ports with multicast groups downstream and also to the router ports. In a 6rd network the snooping switches MUST detect MLD packets in the tunnel between CE and BR as described in Section 6. This requires IPv6 snooping switches to be capable of reading IPv4 protocol field values. A value of 58 indicates that an ICMPv6 packet is Sarikaya Expires April 13, 2012 [Page 12] Internet-Draft Multicast Support for 6rd October 2011 encapsulated. A value of 41 indicates that an IPv6 data packet is encapsulated. The fact that MLD packets are ICMPv6 packets complicates the operation of snooping switch. The switch needs to look further into the packet to correctly identify an MLD packet. In case multicast is supported in Layer 2, BR after receiving a multicast data packet does not attempt to replicate the packet. The packet replication is taken care of by the snooping switches. So Layer 2 multicast support avoids packet duplication at the BR which could be costly in some cases. 8. Security Considerations All AMT control messages are secured using Message Authentication Code (MAC) that is a cryptographic hash of a private secret, the originators address, and the request nonce. AMT data messages are not secured. 6rd Proxy Multicast control and data message security are as described in [RFC5969]. The threats and their mitigation described in [RFC5969] apply to multicast communication as well. 9. IANA Considerations AMT Relay Discovery and AMT Relay Advertisement messages are modified as in Section 5.1. 10. Acknowledgements We would like to specially thank Mark Townsley for his constructive comments. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, June 1999. [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, "Internet Group Management Protocol (IGMP) / Multicast Listener Discovery (MLD)-Based Multicast Forwarding ("IGMP/MLD Proxying")", RFC 4605, August 2006. Sarikaya Expires April 13, 2012 [Page 13] Internet-Draft Multicast Support for 6rd October 2011 [RFC2491] Armitage, G., Schulter, P., Jork, M., and G. Harter, "IPv6 over Non-Broadcast Multiple Access (NBMA) networks", RFC 2491, January 1999. [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, October 2002. [RFC5569] Despres, R., "IPv6 Rapid Deployment on IPv4 Infrastructures (6rd)", RFC 5569, January 2010. [RFC5969] Townsley, W. and O. Troan, "IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) -- Protocol Specification", RFC 5969, August 2010. [RFC4213] Nordmark, E. and R. Gilligan, "Basic Transition Mechanisms for IPv6 Hosts and Routers", RFC 4213, October 2005. [RFC4286] Haberman, B. and J. Martin, "Multicast Router Discovery", RFC 4286, December 2005. [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. [RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base Deployment for Multicast Listener Support in Proxy Mobile IPv6 (PMIPv6) Domains", RFC 6224, April 2011. [I-D.ietf-mboned-auto-multicast] Thaler, D., Talwar, M., Aggarwal, A., Vicisano, L., Pusateri, T., and T. Morin, "Automatic IP Multicast Tunneling", draft-ietf-mboned-auto-multicast-11 (work in progress), July 2011. 11.2. Informative references Sarikaya Expires April 13, 2012 [Page 14] Internet-Draft Multicast Support for 6rd October 2011 Author's Address Behcet Sarikaya Huawei USA 5340 Legacy Dr. Building 175 Plano, TX 75074 Phone: Email: sarikaya@ieee.org Sarikaya Expires April 13, 2012 [Page 15]