MULTIMOB Group H. Asaeda Internet-Draft Keio University Intended status: Standards Track P. Seite Expires: January 14, 2010 France Telecom J. Xia Huawei July 13, 2009 PMIPv6 Extensions for Multicast draft-asaeda-multimob-pmip6-extension-02 Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. 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The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 14, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the Asaeda, et al. Expires January 14, 2010 [Page 1] Internet-Draft PMIPv6 Extensions for Multicast July 2009 document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Asaeda, et al. Expires January 14, 2010 [Page 2] Internet-Draft PMIPv6 Extensions for Multicast July 2009 Abstract This document describes Proxy Mobile IPv6 (PMIPv6) extensions to support IP multicast. The Mobile Access Gateway (MAG) and the Local Mobility Anchor (LMA) are the mobility entities defined in the PMIPv6 protocol. The proposed protocol extension provides; 1) a dedicated multicast tunnel (M-Tunnel) between LMA and MAG, and 2) local routing to deliver IP multicast packets for mobile nodes. This document defines the roles of LMA and MAG to support IP multicast for the mobile nodes. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions and Terminology . . . . . . . . . . . . . . . . . 6 2.1. Conventions Used in This Document . . . . . . . . . . . . 6 2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 6 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. Multicast Communication in PMIPv6 . . . . . . . . . . . . 7 3.2. Multicast Tunnel (M-Tunnel) . . . . . . . . . . . . . . . 8 3.3. Protocol Sequence for Multicast Channel Subscription . . . 9 4. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 12 4.1. LMA Operating As PIM-SM Router . . . . . . . . . . . . . . 12 4.2. LMA Operating As MLD Proxy . . . . . . . . . . . . . . . . 12 5. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 13 5.1. MAG Operating As MLD Proxy . . . . . . . . . . . . . . . . 13 5.2. MAG Operating As PIM-SM Router . . . . . . . . . . . . . . 13 6. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 15 7. Dual-Mode Implementation . . . . . . . . . . . . . . . . . . . 16 8. Handover Process . . . . . . . . . . . . . . . . . . . . . . . 17 8.1. MAG Operating As MLD Proxy . . . . . . . . . . . . . . . . 17 8.2. MAG Operating As Multicast Router . . . . . . . . . . . . 20 8.3. Multicast Context Transfer Data Format . . . . . . . . . . 23 8.4. Proxy Binding Update with Multicast Extension . . . . . . 24 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 10. Security Considerations . . . . . . . . . . . . . . . . . . . 29 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 30 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31 12.1. Normative References . . . . . . . . . . . . . . . . . . . 31 12.2. Informative References . . . . . . . . . . . . . . . . . . 31 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 33 Asaeda, et al. Expires January 14, 2010 [Page 3] Internet-Draft PMIPv6 Extensions for Multicast July 2009 1. Introduction Proxy Mobile IPv6 (PMIPv6) [2] enables network-based mobility for IPv6 mobile nodes (MNs) that do not implement any mobility protocols. The Local Mobility Anchor (LMA) is the topological anchor point to manages the mobile node's binding state. The Mobile Access Gateway (MAG) is an access router or gateway that manages the mobility- related signaling for an MN. An MN is attached to the Proxy Mobile IPv6 Domain (PMIPv6-Domain) that includes LMA and MAG(s), and is able to receive data coming from outside of the PMIPv6-Domain through LMA and MAG. Network-based mobility support for unicast is addressed in [2], while multicast support in PMIPv6 is not discussed in it. LMA and MAG set up a bi-directional tunnel for each MN and forwards MN's traffic. It is possible to deliver multicast packets destined to an MN over the subscriber's bi-directional tunnel. However, it highly wastes network resources when a number of MNs join the same multicast sessions/channels, because independent data copies of each multicast packet is delivered in a unicast manner to MAG (as shown in Figure 1). It also gives the overhead for the data encapsulation and decapsulation at LMA and MAG respectively to forward the same multicast packets. MC1 \ =====MC1 for MN1======> \--> =====MC1 for MN2======> MC2---->LMA===MC1,MC2 for MN3====>MAG =====MC1 for MN4======> =====MC2 for MN5======> : : MC: Multicast packets, ==>: Bi-directional tunnel Figure 1: Multicast channel subscription through subscriber's bi- directional tunnel This document describes PMIPv6 extensions to support IP multicast communication for mobile nodes in PMIPv6-Domain. The proposed protocol extension provides; 1) a dedicated multicast tunnel (M-Tunnel) between LMA and MAG, and 2) local routing to deliver IP multicast packets for mobile nodes. In this document, multicast listener mobility is considered, while multicast source mobility is out of scope of this draft. This document assumes that LMA must be capable of forwarding multicast packets through MAG toward the corresponding mobile nodes. Asaeda, et al. Expires January 14, 2010 [Page 4] Internet-Draft PMIPv6 Extensions for Multicast July 2009 This condition requires LMA to attach multicast networks by supporting multicast routing protocols such as Protocol-Independent Multicast - Sparse Mode (PIM-SM) [3] or other methods, and make traffic and QoS control if needed. And MAG must maintain multicast membership status for the attached mobile nodes at the edge and forwards the multicast data from LMA to the member nodes. This condition requires MAG to support MLD [4]. Each mobile node will connect MAG with a point-to-point access link. Seamless handover must also be considered. When a mobile node receiving multicast data moves from an access link to another access link, the node continuously receives the multicast data through newly attached MAG. The handover procedure should guarantee multicast session continuity and avoid extra packet loss and session disruption. Context transfer will be the required function to support seamless handover, while its effective procedure should be taken into account interaction with multicast communication protocols. The PMIPv6 extension proposed in this document does not require to change unicast communication methods or protocols defined in [2], and therefore both unicast and multicast communications for mobile nodes in PMIPv6-Domain are enabled after all. Asaeda, et al. Expires January 14, 2010 [Page 5] Internet-Draft PMIPv6 Extensions for Multicast July 2009 2. Conventions and Terminology 2.1. Conventions Used in This Document 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 [1]. 2.2. Terminology The following terms used in this document are to be interpreted as defined in the Proxy Mobile IPv6 specification [2]; Mobile Access Gateway (MAG), Local Mobility Anchor (LMA), Mobile Node (MN), Proxy Mobile IPv6 Domain (PMIPv6-Domain), LMA Address (LMAA), Proxy Care-of Address (Proxy-CoA), Mobile Node's Home Network Prefix (MN-HNP), Mobile Node Identifier (MN-Identifier), Proxy Binding Update (PBU), and Proxy Binding Acknowledgement (PBA). As defined in [8], "upstream interface" or "host interface" is an MLD proxy device's interface in the direction of the root of the tree. Each of an MLD proxy device's interfaces that is not in the direction of the root of the tree is called "downstream interface" or "router interface". The Context Transfer Protocol (CXTP) specification [11] describes the mechanism that allows better support for minimizes service disruption during handover. In this document, CXTP is adopted for the multicast context transfer protocol in PMIPv6, and "Multicast-Context Transfer Data (M-CTD)" is defined as the new terminology for transferring MLD state from previously attached MAG (p-MAG) to newly attached MAG (n-MAG). Mobile Node's Policy Profile includes "multicast channel information", whose contents are the same one M-CTD contains, and the mandatory fields of the policy profile specified in [2]. MN's Policy Profile is provided by "policy store" whose definition is the same as of [2], or by CXTP. Asaeda, et al. Expires January 14, 2010 [Page 6] Internet-Draft PMIPv6 Extensions for Multicast July 2009 3. Overview 3.1. Multicast Communication in PMIPv6 Required components to enable IP multicast are multicast routing protocols and host-and-router communication protocols. This document assumes PIM-SM [3] as the multicast routing protocol and MLDv2 [4] or LW-MLDv2 [5] as the host-and-router communication protocol. The architecture of a Proxy Mobile IPv6 domain is shown in Figure 2. LMA and MAG are the core functional entities in PMIPv6-Domain. The entire PMIPv6-Domain appears as a single link from the perspective of each mobile node. +---------+ | Content | | Source | +---------+ | *** *** *** *** *** * ** ** ** ** * * * * Fixed Internet * * * * ** ** ** ** * *** *** *** *** *** / \ +----+ +----+ |LMA1| |LMA2| +----+ +----+ LMAA1 -> | | <-- LMAA2 | | \\ //\\ \\ // \\ \\ // \\ \\ // \\ \\ // \\ \\ // \\ Proxy-CoA1--> | | <-- Proxy-CoA2 +----+ +----+ |MAG1|---{MN2} |MAG2| +----+ | +----+ | | | MN-HNP1 --> | MN-HNP2 | <-- MN-HNP3, MN-HNP4 {MN1} {MN3} Figure 2: Proxy Mobile IPv6 Domain Asaeda, et al. Expires January 14, 2010 [Page 7] Internet-Draft PMIPv6 Extensions for Multicast July 2009 When a mobile node wants to subscribe/unsubscribe a multicast channel, the MN sends MLD Report messages with specifying sender and multicast addresses to the access link. The attached MAG detects this membership information and transfers the information to the corresponding LMA over a multicast tunnel (M-Tunnel described in the next section) when needed, or transfers the information to the adjacent multicast router. When an LMA receives the membership information with MLD Report messages or with PIM Join/Prune messages, it coordinates the corresponding multicast routing tree if necessary. This operation requires multicast routing protocols or proxy functions for LMA. When a MAG detects mobile node's handover, it can proceed the seamless handover procedures. Since both PMIPv6 and multicast protocols (i.e., MLD and PIM-SM) do not have the functions for handover in the original protocol specifications, external functions or protocols such as CXTP [11] can be additionally used with PMIPv6 Proxy Binding Update (PBU). 3.2. Multicast Tunnel (M-Tunnel) MC1 \ \--> MC2---->LMA===MC1,MC2 for MNs====>MAG MC: Multicast packets, ==>: M-Tunnel Figure 3: Multicast channel subscription through M-Tunnel M-Tunnel is a bi-directional tunnel dedicated for MLD message and IP multicast data transmissions between LMA and MAG. It aggregates the same MLD and multicast packets and transmits different multicast channel data as shown in Figure 3. The format of the tunneled multicast packet forwarded from LMA is shown below. "S" and "G" are the same notation used for (S,G) multicast channel. IPv6 header (src= LMAA, dst= Proxy-CoA) /* Tunnel Header */ IPv6 header (src= S, dst= G) /* Packet Header */ Upper layer protocols /* Packet Content*/ Figure 4: Tunneled multicast packet from LMA to MAG When an MLD message is sent from MAG to LMA, the src and dst addresses of tunnel header will be replaced to Proxy-CoA and LMAA, Asaeda, et al. Expires January 14, 2010 [Page 8] Internet-Draft PMIPv6 Extensions for Multicast July 2009 respectively. To convey an MLD message, the src address of the packet header is changed to either LMA's or MAG's link-local address and the dst address of the packet header is assigned based on the MLD's condition. (See Section 5.1.15 and 5.2.14 of [4].) M-Tunnel may be created dynamically when needed and removed when not needed, or implementations MAY choose to use static pre-established M-Tunnel instead of dynamically creating and tearing it down on a need basis. The manner of M-Tunnel creation is similar to the manner of a subscriber's bi-directional tunnel creation as described in Section 5.6.1 of [2]. However, M-Tunnel is not per MN basis, but per MAG basis. The M-Tunnel is shared with all MNs attached to the MAG. 3.3. Protocol Sequence for Multicast Channel Subscription Upon multicast data reception, a mobile node sends MLD Report messages including source and multicast addresses. Although MLDv2 specification [4] permits to use the unspecified address (::) for a host whose interface has not acquired a valid link-local address yet, MLDv2 Report messages MUST be sent with a valid IPv6 link-local source address in PMIPv6 as defined in [9]. As well, MLDv2 Report messages MAY be sent with an IP destination address of FF02:0:0:0:0: 0:0:16, to which all MLDv2-capable multicast routers listen, but the IP unicast address of the attached MAG SHALL be used in many cases as explained in [9]. An MLD proxy [8] can simplify the implementation of multicast data forwarding. By not supporting complicated multicast routing protocols, it reduces the implementation cost and the operational overhead. Reducing the operational overhead will also contribute to faster routing convergence. Another advantage is that an MLD proxy can be independent of the multicast routing protocol used by the core network routers. When a MAG operates as an MLD proxy and receives MLD Report messages from attached mobile nodes, it sends MLD messages on behalf of the mobile nodes. MLD messages are always transferred over the M-Tunnel as seen in Figure 5. MAG operating as an MLD proxy always registers "downstream interface (or router interface)" upon MLD message reception, but does not send MLD Report when the received source and multicast addresses have been already reported to the same LMA through the same "upstream interface (or host interface)". Asaeda, et al. Expires January 14, 2010 [Page 9] Internet-Draft PMIPv6 Extensions for Multicast July 2009 MN1 MN2 MAG LMA | | | | |------MLD Report--------->| | | (S1,G1) join | MLD Report | | | |===== M-Tunnel ===>| | | | |---> PIM (S1,G1) join | | | | | |--MLD Report-->| | | | (S2,G2) join | MLD Report | | | |===== M-Tunnel ===>| | | | |---> PIM (S2,G2) join | | | | | |--MLD Report-->| | | | (S1,G1) join | | | | | | Figure 5: MLD Report Messages Transmission When a MAG operates as a PIM-SM router and receives MLD report messages from attached mobile nodes, it joins the multicast delivery tree by sending PIM join messages to its neighboring routers. At the same time, the MAG sends MLD report messages with the Hold extension [9] with the corresponding multicast channel information to the LMA (Figure 6). When receiving the MLD Hold, the LMA joins the multicast delivery tree but does not forward multicast data to the MAG. The idea is to make the LMA ready to forward data. When an MN changes the network, it will be able to continuously receive multicast data from the LMA, until a new MAG completes the handover routing update (detailed in Section 8). Asaeda, et al. Expires January 14, 2010 [Page 10] Internet-Draft PMIPv6 Extensions for Multicast July 2009 MN1 MN2 MAG LMA | | | | |------MLD Report--------->| | | (S1,G1) join |---> PIM (S1,G1) join | | | | | | | MLD Hold | | | |===== M-Tunnel ===>| | | | |---> PIM (S1,G1) join | | | | (No data forwarding) | |--MLD Report-->| | | | (S2,G2) join |---> PIM (S2,G2) join | | | | | | | MLD Hold | | | |===== M-Tunnel ===>| | | | |---> PIM (S2,G2) join | | | | (No data forwarding) | |--MLD Report-->| | | | (S1,G1) join | | | | | | Figure 6: MLD Report Messages Transmission when MAG acts as a router Whether a MAG works as an MLD proxy or a PIM-SM router, it MAY store multicast channel information reported by attached mobile nodes in the MN's policy profile (as defined in [2]). This information may be used by the new MAG during the handover process (see Section 8). Asaeda, et al. Expires January 14, 2010 [Page 11] Internet-Draft PMIPv6 Extensions for Multicast July 2009 4. Local Mobility Anchor Operation 4.1. LMA Operating As PIM-SM Router An LMA is responsible for maintaining the mobile node's reachability state and is the topological anchor point for the mobile node's home network prefix(es). When an LMA acts as a PIM-SM [3] multicast router, it serves MAGs as listener nodes when the MAGs act as MLD proxies, or as downstream routers when the MAGs act as PIM-SM routers. Each MAG is connected through an M-Tunnel for multicast communication. An LMA sets up the multicast state and joins the group. Multicast packets are tunneled to a MAG that requested to receive the corresponding multicast session after being received by the LMA. The MAG forwards these packets to the MN according to the multicast listener state in the MAG. 4.2. LMA Operating As MLD Proxy An LMA may act as an MLD proxy [8]. When LMA acts as an MLD proxy, multicast data is forwarded from outside to mobile nodes through an M-Tunnel to MAG. When LMA acts as an MLD proxy, the attached MAGs must also act as an MLD proxy. Asaeda, et al. Expires January 14, 2010 [Page 12] Internet-Draft PMIPv6 Extensions for Multicast July 2009 5. Mobile Access Gateway Operation The mobile access gateway (MAG) is the entity that performs the mobility management on behalf of a mobile node. MAG is responsible for detecting the mobile node's movements to and from the access link. 5.1. MAG Operating As MLD Proxy [2] supports only point-to-point access link types for MAG and MN connection; hence an MN and a MAG are the only two nodes on an access link, where the link is assumed to be multicast capable. Since a MAG will deal with mobile nodes' membership states reported by a large number of the downstream mobile nodes with MLD Report messages, the protocol scalability must be taken into account. A MAG acting as an MLD proxy sends MLD Query messages to all or some of attached mobile nodes. After MAG receives MLD Report messages from the mobile nodes, it forwards the MLD Report messages on behalf of these mobile nodes to LMA. Mobile nodes send MLD messages with their link-local address to MAG, and MAG forwards the MLD messages through the M-Tunnel to LMA with the MAG's link-local address. An MLD proxy requires that the upstream and downstream interfaces MUST be statistically configured. As well, MAG MUST configure an upstream interface that is the interface MLD Report messages are sent to LMA and downstream interfaces that are the interfaces MLD Report messages are received from mobile nodes. This upstream interface is the M-Tunnel end-point at the MAG. 5.2. MAG Operating As PIM-SM Router The optimal multicast routing path does not always include LMA, especially in local routing as described in Section 6.10.3 of [2]. The local routing option is designed to support node-to-node communication within PMIPv6-Domain where a local content source exists. To enable local routing, MAG MUST run multicast routing protocols to attach the optimal multicast routing path. This document assume use of PIM-SM [3] as the supported multicast routing protocol. Because of its implementation or operational costs, operators may not want to support PIM-SM on MAG. However, an MLD proxy requires to statically configure its upstream interface, which is an M-Tunnel as specified in Section 5.1, to receive all multicast data. Therefore, if operators take into account the case that an upstream interface for the optimized multicast path is NOT an M-Tunnel to LMA but other Asaeda, et al. Expires January 14, 2010 [Page 13] Internet-Draft PMIPv6 Extensions for Multicast July 2009 interface, and want MAG to "dynamically select" optimized routing path, MAG MUST act as a PIM-SM router. Asaeda, et al. Expires January 14, 2010 [Page 14] Internet-Draft PMIPv6 Extensions for Multicast July 2009 6. Mobile Node Operation Mobile nodes attached to MAG can behave as the regular receiver hosts. A mobile node sends MLD messages to MAG when it wants to subscribe and unsubscribe IP multicast channels. And mobile nodes do not change their behaviors whether MAG is acting as an MLD proxy or a PIM-SM router. All MLD related considerations are described in [9], which will give some advantage for its resource saving and seamless handover for PMIPv6 multicast. [2] allows a mobile node is a router. However, to avoid the complexity, in this document, MN may behave as an MLD proxy [8] but should not act as a PIM-SM router, when MN needs to forward multicast data to its downstream nodes. Asaeda, et al. Expires January 14, 2010 [Page 15] Internet-Draft PMIPv6 Extensions for Multicast July 2009 7. Dual-Mode Implementation Operators may want to make LMA or MAG act as both an MLD proxy and a PIM-SM multicast router to support different customers. This document proposes a "dual-mode" implementation that enables LMA or MAG to support both an MLD proxy function and a multicast routing function simultaneously. To simplify mobile node's handover procedure among dual-mode MAGs, p-MAG and n-MAG should not change the behaviors for the same mobile node. For instance, in dual-mode, if p-MAG that a mobile node attaches is working as an MLD proxy, n-MAG that the mobile node will attach must also work as an MLD proxy. It is same as of PIM-SM. Asaeda, et al. Expires January 14, 2010 [Page 16] Internet-Draft PMIPv6 Extensions for Multicast July 2009 8. Handover Process MAG is responsible for detecting the mobile node's movements to and from the access link and for initiating binding registrations to the mobile node's LMA. MAG tracks the mobile node's movements to and from the access link and for signaling the mobile node's LMA. In PMIPv6, it SHOULD NOT require for mobile nodes to initiate to re- subscribe multicast channels, and MAG SHOULD keep multicast channel subscription status for mobile nodes even if they attach a different MAG in PMIPv6-Domain. In this section, mobility handover procedures are described. 8.1. MAG Operating As MLD Proxy When MAG operates as an MLD proxy, there are two possible ways to proceed MLD listener handover; MLD listener handover with CXTP and MLD listener handover with MN's Policy Profile. A Proxy Binding Update with multicast extension (PBU-M) (defined in Section 8.4) is always used to request the LMA to forward multicast data. The MLD listener handover with CXTP shown in Figure 7 is defined as follows. 1. Whenever MN attaches to n-MAG, the n-MAG requests multicast context transfer to p-MAG. 2. p-MAG provides the multicast states corresponding to the moving MN-Identifier to n-MAG. p-MAG utilizes a context transfer protocol to deliver MN's profile to n-MAG, and sends Multicast Context Transfer Data (M-CTD) (defined in Section 8.3) to n-MAG. 3. n-MAG records MN's profile including multicast channel information. 4. n-MAG subscribes multicast channel on behalf of MN. PBU-M is transmitted to LMA. If the received PBA message has the Status field value set to 0 (Proxy Binding Update accepted), the MAG MUST establish an M-Tunnel for forwarding corresponding multicast data if there is no existing M-Tunnel to that LMA. Asaeda, et al. Expires January 14, 2010 [Page 17] Internet-Draft PMIPv6 Extensions for Multicast July 2009 MN p-MAG n-MAG LMA | | | | |-MLD Report->| MLD Report | | |============= M-Tunnel ===========>| | | | |---> PIM join | | Multicast data | |<------------|<============ M-Tunnel ============| | | | | Detach | | | | | | | Attach | | | | | | | |------------RS-------------->| | | |<---CT-Req-----| | | | | | | |-----CXTP----->| | | | M-CTD | MLD Report | | | |-------PBU-M------>| | | | | | | |<-------PBA--------| | | | | |<-----------RA---------------| | | | | | | | | Multicast data | |<----------------------------|<==== M-Tunnel ====| | | | | |<---------MLD Query----------| MLD Report | |----------MLD Report-------->|===== M-Tunnel ===>| | | | | Figure 7: MLD listener handover with CXTP After MN attaches to n-MAG, the multicast data will be delivered to the MN immediately. MN's multicast membership state is maintained with MLD Query and Report messages exchanged by MN and n-MAG. Mobile node's multicast state is kept in MN's profile. If MN's policy profile is stored in a policy store [2], it is not necessary to use a context transfer protocol between p-MAG and n-MAG. In such a case, n-MAG obtains MN's multicast state by the same mechanism used to acquire MN-ID and profile during MN's attachment process [2]. The procedure for MLD listener handover with MN's Policy Profile (Figure 8) is shown as follows. Asaeda, et al. Expires January 14, 2010 [Page 18] Internet-Draft PMIPv6 Extensions for Multicast July 2009 1. n-MAG obtains the MN-Identifier and learns multicast channel information described in Mobile Node's Policy Profile associated to this MN-Identifier. 2. n-MAG prepares the PBU-M that includes multicast channel information the MN has subscribed. 3. n-MAG transmits PBU-M to LMA. If the received PBA message has the Status field value set to 0 (Proxy Binding Update accepted), the MAG MUST establish an M-Tunnel for forwarding corresponding multicast data if there is no existing M-Tunnel to that LMA. 4. LMA forwards requested multicast data through an M-Tunnel between the LMA and n-MAG. MN p-MAG n-MAG LMA | | | | |-MLD Report->| MLD Report | | |============= M-Tunnel ===========>| | | | |---> PIM join | | Multicast data | |<------------|<============ M-Tunnel ============| | | | | Detach | | | | | | | Attach | MN attachment event | | | (Acquire MN-Id and Profile) | | | | | |------------RS-------------->| | | | | MLD Report | | | |-------PBU-M------>| | | | | | | |<-------PBA--------| | | | | |<-----------RA---------------| | | | | | | | | Multicast data | |<----------------------------|<==== M-Tunnel ====| | | | | |<---------MLD Query----------| MLD Report | |----------MLD Report-------->|===== M-Tunnel ===>| | | | | Figure 8: MLD listener handover with MN's Policy Profile Asaeda, et al. Expires January 14, 2010 [Page 19] Internet-Draft PMIPv6 Extensions for Multicast July 2009 8.2. MAG Operating As Multicast Router MAG operating PIM-SM multicast routing protocol joins the multicast delivery tree when an attached mobile node subscribes a multicast channel. In order to reduce handover latency, LMA forwards multicast data to n-MAG until n-MAG has completed to join the multicast delivery tree. A Proxy Binding Update with multicast extension (PBU-M) is always used to request the LMA to forward multicast data. When MAG operates PIM-SM routing protocol, leveraging CXTP is the possible handover scenario with the following procedure. 1. Whenever MN attaches to n-MAG, the n-MAG requests multicast context transfer to p-MAG. 2. p-MAG provides the multicast states corresponding to the moving MN-Identifier to n-MAG. p-MAG utilizes a context transfer protocol to deliver MN's profile to n-MAG, and sends M-CTD to n-MAG. 3. n-MAG initiates the process to subscribe the multicast channels. 4. n-MAG requests LMA to forward multicast data in the meantime. n-MAG prepares the PBU-M that includes multicast channel information the MN has subscribed and has not yet received at n-MAG. 5. LMA forwards requested multicast data through an M-Tunnel between the LMA and n-MAG. 6. Whenever n-MAG joins the multicast delivery tree, it notifies the LMA to stop forwarding the data and switches to the optimal multicast routing path. Asaeda, et al. Expires January 14, 2010 [Page 20] Internet-Draft PMIPv6 Extensions for Multicast July 2009 MN p-MAG n-MAG LMA | | | | |--MLD Report->| MLD Hold | | |=========== M-Tunnel =============>| | |---> PIM join | |---> PIM join | | | | |<--Multicast--| | | | data | | | Detach | | | | | | | Attach | | | | | | | |-------------RS-------------->| | | | | | | |<---CT-Req-----| | | | | | | |-----CXTP----->| | | | M-CTD |---> PIM join | | | | | | | | MLD Report (join) | | | |-------PBU-M------>| | | | | | | |<-------PBA--------| | | | | |<------------RA---------------| | | | | | | | | Multicast data | | | |<==== M-Tunnel ====| |<-------Multicast data--------| | | | | | | | Join process completed | | | | | | | | MLD Hold | | | |-------PBU-M------>| | | | | |<-------Multicast data--------| | | | | | Figure 9: PIM-SM handover with CXTP The following procedure is for PIM-SM handover using MN's Policy Profile. 1. When n-MAG detects a mobile node movement, it obtains the MN- Identifier and learns multicast channel information described in Mobile Node's Policy Profile associated to this MN-Identifier. Asaeda, et al. Expires January 14, 2010 [Page 21] Internet-Draft PMIPv6 Extensions for Multicast July 2009 2. n-MAG prepares the PBU-M that includes multicast channel information the MN has subscribed and has not yet received at n-MAG. 3. n-MAG transmits PBU-M to LMA. If the received PBA message has the Status field value set to 0, the MAG MUST establish an M-Tunnel for forwarding corresponding multicast data if there is no existing M-Tunnel to that LMA. 4. LMA subscribes requested multicast channels and forwards the data through an M-Tunnel between the LMA and n-MAG. 5. Whenever n-MAG joins the multicast delivery tree, it notifies the LMA to stop forwarding the data and switches to the optimal multicast routing path. Asaeda, et al. Expires January 14, 2010 [Page 22] Internet-Draft PMIPv6 Extensions for Multicast July 2009 MN p-MAG n-MAG LMA | | | | |--MLD Report->| | | | | MLD Hold | | |=========== M-Tunnel =============>| | |---> PIM join | |---> PIM join | | | | |<--Multicast--| | | | data | | | | | | | Detach | | | | | | | Attach | MN attachment event | | | (Acquire MN-Id and Profile) | |-------------RS-------------->| | | | |---> PIM join | | | | | | | | MLD Report (join) | | | |-------PBU-M------>| | | | | | | |<-------PBA--------| | | | | |<------------RA---------------| | | | | | | | | Multicast data | | | |<==== M-Tunnel ====| |<-------Multicast data--------| | | | | | | | Join process completed | | | | | | | | MLD Hold | | | |-------PBU-M------>| | | | | |<-------Multicast data--------| | | | | | Figure 10: PIM-SM handover with MN's Policy Profile 8.3. Multicast Context Transfer Data Format The following information is necessary to keep mobile node's membership status, and hence M-CTD includes the information. 1. Receiver address - indicates an address of a receiver host sending the Current-State Report. Asaeda, et al. Expires January 14, 2010 [Page 23] Internet-Draft PMIPv6 Extensions for Multicast July 2009 2. Last membership report - indicates the time that the router receives the last Current-State Report. 3. Filter mode - indicates either INCLUDE or EXCLUDE as defined in [4]. 4. Source addresses and multicast address - indicates the address pair that the receiver has joined. 8.4. Proxy Binding Update with Multicast Extension 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence # | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |A|H|L|K|M|R|P|C| Reserved | Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Mobility options . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 11: Proxy Binding Update Message with Multicast Extension A Binding Update message that is sent by MAG to LMA is referred to as the "Proxy Binding Update" message. A new flag (C) is included in the Binding Update message with multicast extension. The rest of the Binding Update message format remains the same as defined in [10] and with the additional (R), (M), and (P) flags, as specified in [12], [13], and [2], respectively. Multicast Channel Subscription Flag A new flag (C) is included in the Binding Update message to indicate to LMA that the Binding Update message is a multicast channel subscription. When (C) flag is specified in PBU-M message, the mobility options field includes the same information of MLDv2 Report message [4]: Asaeda, et al. Expires January 14, 2010 [Page 24] Internet-Draft PMIPv6 Extensions for Multicast July 2009 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 = 143 | Reserved | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |Nr of Mcast Address Records (M)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Multicast Address Record [1] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Multicast Address Record [2] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | . . . | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Multicast Address Record [M] . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 12 Each Multicast Address Record has the following internal format: Asaeda, et al. Expires January 14, 2010 [Page 25] Internet-Draft PMIPv6 Extensions for Multicast July 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record Type | Aux Data Len | Number of Sources (N) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | * * | | * Multicast Address * | | * * | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | * * | | * Source Address [1] * | | * * | | +- -+ | | * * | | * Source Address [2] * | | * * | | +- -+ . . . . . . . . . +- -+ | | * * | | * Source Address [N] * | | * * | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Auxiliary Data . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 13 Asaeda, et al. Expires January 14, 2010 [Page 26] Internet-Draft PMIPv6 Extensions for Multicast July 2009 All the above fields contain data with the same definitions in [4]. Asaeda, et al. Expires January 14, 2010 [Page 27] Internet-Draft PMIPv6 Extensions for Multicast July 2009 9. IANA Considerations This document creates a new registry for the flags in the Binding Update message called the "Binding Update Flags". The following flags are reserved: (A) 0x8000 [RFC3775] (H) 0x4000 [RFC3775] (L) 0x2000 [RFC3775] (K) 0x1000 [RFC3775] (M) 0x0800 [RFC4140] (R) 0x0400 [RFC3963] (P) 0x0200 [RFC5213] This document reserves a new flag (C) for "Proxy Binding Update with Multicast Extension" as described in Section 8.4 as follows: (C) 0x0100 The rest of the values in the 16-bit field are reserved. New values can be assigned by Standards Action or IESG approval. Asaeda, et al. Expires January 14, 2010 [Page 28] Internet-Draft PMIPv6 Extensions for Multicast July 2009 10. Security Considerations TBD. Asaeda, et al. Expires January 14, 2010 [Page 29] Internet-Draft PMIPv6 Extensions for Multicast July 2009 11. Acknowledgements Many of the specifications described in this document are discussed and provided by the multimob mailing-list. Asaeda, et al. Expires January 14, 2010 [Page 30] Internet-Draft PMIPv6 Extensions for Multicast July 2009 12. References 12.1. Normative References [1] Bradner, S., "Key words for use in RFCs to indicate requirement levels", RFC 2119, March 1997. [2] Gundavelli, S, Ed., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [3] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006. [4] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. [5] Liu, H., Cao, W., and H. Asaeda, "Lightweight IGMPv3 and MLDv2 Protocols", draft-ietf-mboned-lightweight-igmpv3-mldv2-05.txt (work in progress), May 2009. [6] Deering, S., Fenner, W., and B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", RFC 2710, October 1999. [7] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, August 2006. [8] 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. [9] Asaeda, H. and T. Schmidt, "IGMP and MLD Extensions for Mobile Hosts and Routers", draft-asaeda-multimob-igmp-mld-mobility-extensions-03.txt (work in progress), July 2009. [10] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in IPv6", RFC 3775, June 2004. [11] Loughney, Ed., J., Nakhjiri, M., Perkins, C., and R. Koodli, "Context Transfer Protocol (CXTP)", RFC 4067, July 2005. 12.2. Informative References [12] Devarapalli, V., Wakikawa, R., Petrescu, A., and P. Thubert, "Network Mobility (NEMO) Basic Support Protocol", RFC 3963, Asaeda, et al. Expires January 14, 2010 [Page 31] Internet-Draft PMIPv6 Extensions for Multicast July 2009 January 2005. [13] Soliman, H., Castelluccia, C., El Malki, K., and L. Bellier, "Hierarchical Mobile IPv6 Mobility Management (HMIPv6)", RFC 4140, August 2005. Asaeda, et al. Expires January 14, 2010 [Page 32] Internet-Draft PMIPv6 Extensions for Multicast July 2009 Authors' Addresses Hitoshi Asaeda Keio University Graduate School of Media and Governance 5322 Endo Fujisawa, Kanagawa 252-8520 Japan Email: asaeda@wide.ad.jp URI: http://www.sfc.wide.ad.jp/~asaeda/ Pierrick Seite France Telecom 4, rue du Clos Courtel BP 91226, Cesson-Sevigne 35512 France Email: pierrick.seite@orange-ftgroup.com Jinwei Xia Huawei Technologies Co., Ltd. Huihong Mansion, No.91 Baixia Rd. Nanjing, Jiangsu 21001 China Email: xiajinwei@huawei.com Asaeda, et al. Expires January 14, 2010 [Page 33]