MULTIMOB Working Group JC. Zuniga Internet-Draft InterDigital Intended status: Experimental LM. Contreras Expires: August 29, 2013 Telefonica I+D CJ. Bernardos UC3M S. Jeon Instituto de Telecomunicacoes Y. Kim Soongsil University February 25, 2013 Multicast Mobility Routing Optimizations for Proxy Mobile IPv6 draft-ietf-multimob-pmipv6-ropt-03 Abstract The MULTIMOB group has specified a base solution to support IP multicasting in a PMIPv6 domain [RFC6224]. In this document, some enhancements to the base solution are described. These enhancements include the use of a multicast tree mobility anchor as the topological anchor point for multicast traffic, as well as a direct routing option where the MAG can provide access to multicast content in the local network. These enhancements provide benefits such as reducing multicast traffic replication and supporting different PMIPv6 deployment scenarios. 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 August 29, 2013. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the Zuniga, et al. Expires August 29, 2013 [Page 1] Internet-Draft Multicast Mobility Routing Optimizations February 2013 document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.1. Multicast Tree Mobility Anchor (subscription via MTMA) . . 5 3.2. Direct Routing (subscription via direct routing) . . . . . 6 4. Mobile Access Gateway Operation . . . . . . . . . . . . . . . 8 4.1. Extensions to Binding Update List Data Structure . . . . . 8 4.2. MAG as MLD proxy . . . . . . . . . . . . . . . . . . . . . 8 4.2.1. MTMA mode (subscription via MTMA) . . . . . . . . . . 8 4.2.2. Direct Routing mode (subscription via direct routing) . . . . . . . . . . . . . . . . . . . . . . . 10 5. Local Mobility Anchor Operation . . . . . . . . . . . . . . . 13 5.1. Dynamic IP Multicast Selector Option . . . . . . . . . . . 13 5.1.1. Option application rules . . . . . . . . . . . . . . . 13 5.1.2. Option format . . . . . . . . . . . . . . . . . . . . 13 6. Multicast Tree Mobility Anchor Operation . . . . . . . . . . . 14 6.1. Conceptual Data Structures . . . . . . . . . . . . . . . . 15 7. Mobile Node Operation . . . . . . . . . . . . . . . . . . . . 15 8. IPv4 support . . . . . . . . . . . . . . . . . . . . . . . . . 15 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 11. Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 12.1. Normative References . . . . . . . . . . . . . . . . . . . 16 12.2. Informative References . . . . . . . . . . . . . . . . . . 17 Appendix A. MTMA Deployment Use Cases . . . . . . . . . . . . . . 18 A.1. PMIPv6 domain with ratio 1:1 . . . . . . . . . . . . . . . 18 A.2. PMIPv6 domain with ratio N:1 . . . . . . . . . . . . . . . 18 A.3. PMIPv6 domain with ratio 1:N . . . . . . . . . . . . . . . 20 A.4. PMIPv6 domain with H-LMA . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24 Zuniga, et al. Expires August 29, 2013 [Page 2] Internet-Draft Multicast Mobility Routing Optimizations February 2013 1. Introduction Proxy Mobile IPv6 [RFC5213] is a network-based approach to solving the IP mobility problem. In a Proxy Mobile IPv6 (PMIPv6) domain, the Mobile Access Gateway (MAG) behaves as a proxy mobility agent in the network and performs the mobility management on behalf of the Mobile Node (MN). The Local Mobility Anchor (LMA) is the home agent for the MN and the topological anchor point. PMIPv6 was originally designed for unicast traffic. However, a PMIPv6 domain may handle data from both unicast and multicast sources. The Internet Group Management Protocol (IGMPv3) [RFC3376] is used by IPv4 hosts to report their IP multicast group memberships to neighboring multicast routers. Multicast Listener Discovery (MLDv2) [RFC3810] is used in a similar way by IPv6 routers to discover the presence of IPv6 multicast hosts. Also, the IGMP/MLD proxy [RFC4065] specification allows an intermediate (i.e., edge) node to appear as a multicast router to downstream hosts, and as a host to upstream multicast routers. IGMP and MLD related protocols however were not originally designed to address IP mobility of multicast listeners (i.e., IGMP and MLD protocols were originally designed for fixed networks). The MULTIMOB group has specified a base solution to support IP multicast listener mobility in a PMIPv6 domain [RFC6224], which describes deployment options without modifying mobility and multicast protocol standards. The PMIPv6 allows a MAG to establish multiple PMIPv6 tunnels with different LMAs, e.g., up to one per MN. In the presence of multicast traffic, multiple instances of the same traffic can converge to the same MAG. Hence, when IP multicasting is applied into PMIPv6, it leads to redundant traffic at a MAG. This is the so- called tunnel convergence problem. In order to address this issue, a comprehensive solution is proposed in this document, consisting of two complementary enhancements: multicast anchor and direct routing. The former enhancements makes use of a multicast tree mobility anchor (MTMA) as the topological anchor point for remotely delivering multicast traffic, while the latter enhancement uses direct routing taking advantage of local multicast source availability, allowing a MAG to connect directly to a multicast router for simple access to local content. Neither of the two schemes has any impact on the MN to support multicast listener mobility. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", Zuniga, et al. Expires August 29, 2013 [Page 3] Internet-Draft Multicast Mobility Routing Optimizations February 2013 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [RFC2119]. This document uses the terminology defined in [RFC5213], [RFC6275], and [RFC3810]. Specifically, the definition of PMIPv6 domain is reused from [RFC5213] and reproduced here for completeness. Proxy Mobile IPv6 Domain (PMIPv6-Domain): Proxy Mobile IPv6 domain refers to the network where the mobility management of a mobile node is handled using the Proxy Mobile IPv6 protocol as defined in [RFC5213]. The Proxy Mobile IPv6 domain includes local mobility anchors and mobile access gateways between which security associations can be set up and authorization for sending Proxy Binding Updates on behalf of the mobile nodes can be ensured. In this draft we refine such definition from the point of view of the kind of traffic served to the MN in the following way: PMIPv6 unicast domain: PMIPv6 unicast domain refers to the network covered by one LMA for unicast service. This service supports mobility as the MN moves from one MAG to another one, both associated to the same LMA regarding the MN unicast traffic. PMIPv6 multicast domain: PMIPv6 multicast domain refers to the network covered by one network element named MTMA (defined below) for multicast service in such a way that an MN using that service is not aware of mobility as it moves from one MAG to another. From the definitions above, it can be stated that a PMIPv6 domain can have several PMIPv6 unicast domains and PMIPv6 multicast domains. Additionally, some other definitions are introduced, as follows. MTMA or multicast tree mobility anchor: An entity working as topological anchor point for multicast traffic. H-LMA or Hybrid-LMA: An entity dedicated to both unicast and multicast services, that is able to work as both LMA and MTMA simultaneously. Direct routing: This scheme uses the native multicast infrastructure for retrieving multicast data. For an operator having its own local content, this technique also includes the case where the content source is directly connected to the MAG. Subscription via MTMA: Multicast subscription mode in which the content is retrieved from the remote (e.g., home) MTMA. Zuniga, et al. Expires August 29, 2013 [Page 4] Internet-Draft Multicast Mobility Routing Optimizations February 2013 Subscription via direct routing: Multicast subscription mode in which the content is retrieved using direct routing from the local domain. 3. Overview This document specifies a solution to the tunnel convergence problem composed of two operational modes that can be used as complementary enhancements: multicast tree mobility anchor (MTMA) and direct routing. Next, each one of these two operational modes is introduced. 3.1. Multicast Tree Mobility Anchor (subscription via MTMA) An MTMA is used used to serve as the mobility anchor for multicast traffic. Typically, the MTMA will be used to get access to remote multicast content. The MTMA connects to the MAG as described in [RFC6224] and it can reuse native PMIPv6 features such as tunnel establishment and security [RFC5213], heartbeat [RFC5847], etc. Unicast traffic will go normally to the LMAs in the PMIPv6 domain as described in [RFC5213]. A MAG connecting to the MTMA acts as a MLD proxy. This section describes how the MTMA works in scenarios of MN attachment and multicast mobility. It concentrates on the case of both LMA and MTMA defining a unique PMIPv6 domain. Some other different deployment scenarios are presented in Appendix A. Figure 1 shows an example of a PMIPv6 domain supporting multicast mobility. The LMA is dedicated to unicast traffic, and the MTMA is dedicated to multicast traffic. The MTMA can be considered to be a form of upstream multicast router with tunnel interfaces allowing subscription via MTMA for the MNs. Note that there can be multiple LMAs for unicast traffic in a given PMIPv6 domain (not shown in Figure 1 for simplicity). Similarly, more than one MTMA could be deployed by the operator, for example to serve different multicast groups (not shown in Figure 1). This would require support for MLD proxy with multiple interfaces [I-D.ietf-multimob-pmipv6-source], [I-D.contreras-multimob-multiple-upstreams], [I-D.asaeda-pim-mldproxy-multif]. As shown in Figure 1, MAG1 may connect to both unicast (LMAs) and multicast (MTMAs) entities. Thus, a given MN may simultaneously receive both unicast and multicast traffic. In Figure 1, MN1 and MN2 receive unicast traffic, multicast traffic, or both, whereas MN3 receives multicast traffic only. Zuniga, et al. Expires August 29, 2013 [Page 5] Internet-Draft Multicast Mobility Routing Optimizations February 2013 +--------------+ |Content Source| +--------------+ | | *** *** *** *** *** *** *** *** * ** ** ** * * ** ** ** * * * * * * Unicast Traffic * * Multicast Traffic * * * * * * ** ** ** * * ** ** ** * *** *** *** ** *** *** *** *** | | | | | | +-----+ +------+ Unicast | LMA | | MTMA | Multicast Anchor +-----+ +------+ Anchor \\ // || \\ // || \\ // || \\ // || \\ // || \\ // || \\ // || \\ // || \\ // || +-----+ +-----+ | MAG1| | MAG2| MLD Proxy +-----+ +-----+ | | | | | | {MN1} {MN2} {MN3} Figure 1: Architecture of Multicast Tree Mobility Anchor (MTMA) 3.2. Direct Routing (subscription via direct routing) Direct routing uses a native multicast infrastructure, allowing a MAG to directly connect to a multicast router (as next hop) in the PMIPv6 domain. A MAG acts as a MLD proxy. The main purpose of direct routing is to provide optimal connectivity for local content. As a consequence, it alleviates the MTMA of the channel management and data delivery of locally available content. Unicast traffic will go as normally to the LMAs in the PMIPv6 domain. This section describes how the direct routing works in scenarios of Zuniga, et al. Expires August 29, 2013 [Page 6] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MN attachment and multicast mobility. Multicast Tree : : || - PMIPv6 Tunnel +----------+ +----------+ | - Multicast Data Path | LMA | | MR | +----------+ +----------+ || \\ / | || \\ / | || \\ / | || \\ / | || \\ / | || \\ / | || \\ | || /\\ | || / \\ | || / \\ | || / \\ | || / \\ | +----------+ +----------+ | P-MAG | | N-MAG | MLD Proxy +----------+ +----------+ : : +------+ +------+ | MN | -----> | MN | +------+ +------+ Figure 2: Architecture for direct routing based PMIPv6 multicasting Figure 2 shows the architecture for the local routing case using native multicasting infrastructure [I-D.deng-multimob-pmip6-requirement]. The LMA is dedicated to unicast traffic, and the multicast traffic is obtained from an upstream multicast router present in the PMIPv6 domain. Note that there can be multiple LMAs for unicast traffic (not shown in Figure 1 for simplicity) in a given PMIPv6 domain. As shown in Figure 2, a MAG may connect to both unicast (LMA) and multicast (MR) routers. Thus, a given MN may simultaneously receive both unicast and multicast traffic. As seen in Figure 2, each MAG has a direct connection (i.e., not using the tunnel interface) with a multicast router. To facilitate IGMP/MLD signaling and multicast traffic forwarding, an MLD proxy function defined in [RFC4605] SHOULD be implemented in the MAG. There SHOULD be direct connectivity between the MAG and the local Zuniga, et al. Expires August 29, 2013 [Page 7] Internet-Draft Multicast Mobility Routing Optimizations February 2013 multicast router (or additional MLD proxy). 4. Mobile Access Gateway Operation This section describes the operation of the mobile access gateway, considering that the MAG incorporates MLD proxy functions as per [RFC4605]. 4.1. Extensions to Binding Update List Data Structure The binding update list (BUL) in the MAG must be updated to be able to handle the fact that more than one entity (i.e., LMA and MTMA) may be serving the mobile node for different kind of traffic. 4.2. MAG as MLD proxy 4.2.1. MTMA mode (subscription via MTMA) In case of subscription via MTMA, all MAGs that are connected to the MTMA must support the MLD proxy funtion [RFC4605]. Specifically in Figure 1, each of the MAG1-MTMA and MAG2-MTMA tunnel interfaces define an MLD proxy domain. The MNs are considered to be on the downstream interface of the MLD proxy (of the MAG), and the MTMA is considered to be on the upstream interface (of the MAG) as per [RFC4605]. Note that the MAG could also be an IGMP proxy. For brevity this document will refer primarily to MLD proxy, but all references to "MLD proxy" should be understood to also include "IGMP/ MLD proxy" functionality. Figure 3 shows the procedure when MN1 attaches to a MAG, and establishes associations with the LMA (unicast) and the MTMA (multicast). Zuniga, et al. Expires August 29, 2013 [Page 8] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MN1 MAG LMA MTMA | (MLD Proxy) (Unicast) (Multicast) MN attaches to MAG1 | | | | | | | |----Rtr Sol--------->| | | | |--PBU---->| | | | | | | |<----PBA--| | | | | | | |=Unicast==| | | | Tunnel | | |<---------Rtr Adv----| | | | | | | |< ------ Unicast Traffic------->| | | | | | | |==Multicast Tunnel===| | | | | |<-------MLD Query----| | | | | | | MN requires | | | multicast services | | | | | | | |----MLD Report (G)-->| | | | | | | | |----Aggregated------>| | | MLD Report (G) | | | | | | | | | |<-----------Multicast Traffic------------->| | | | | Figure 3: MN Attachment and Multicast Service Establishment for MTMA In Figure 3, the MAG first establishes the PMIPv6 tunnel with LMA for unicast traffic as defined in [RFC5213] after being triggered by the Router Solicitation message from MN1. Unicast traffic will then flow between MN1 and LMA. For multicast traffic, a multicast tunnel may have been pre- configured between MAG and MTMA, or may be dynamically established when the first MN appears at the MAG. MN1 sends the MLD report message (when required by its upper layer applications) as defined in [RFC3810] in response to an MLD Query from MAG. The MAG, acting as a MLD Proxy defined in [RFC4605], will then send an Aggregated MLD Report to the multicast anchor, MTMA (assuming that this is a new multicast group which the MAG had not previously subscribed to). Multicast traffic will then flow from the Zuniga, et al. Expires August 29, 2013 [Page 9] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MTMA towards MN1. We next consider a mobility scenario in which MN1 with an ongoing multicast subscription moves from one MAG to another to MAG. Aaccording to the baseline solution signaling method described in [RFC6224], after MN1 mobility, the new MAG acting in its role of MLD proxy will send an MLD Query to the newly observed MN on its downlink. Assuming that the subsequent MLD Report from MN1 requests membership for a new multicast group (from the new MAG's point of view), this will then result in an Aggregated MLD Report being sent to the MTMA from the new MAG. This message will be sent through a multicast tunnel between the new MAG and MTMA (pre-established or dynamically established). When MN1 detaches, the old MAG may keep the multicast tunnel with the multicast MTMA if there are still other MNs using the multicast tunnel. Even if there are no MNs currently on the multicast tunnel, the old MAG may decide to keep the multicast tunnel temporariliy for potential future use. As discussed above, existing MLD (and MLD proxy) signaling will handle a large part of the multicast mobility management for the MN. 4.2.2. Direct Routing mode (subscription via direct routing) In this case, the MLD proxy instance is configured to obtain the multicast traffic locally. Figure 4 shows an example of multicast service establishment. The MAG first establishes the PMIPv6 tunnel with the LMA for unicast traffic as defined in [RFC5213] after being triggered by the Router Solicitation message from the MN. Unicast traffic will then flow between the MN and LMA. For multicast traffic, it is assumed that the upstream interface of the MLD proxy instance has been configured pointing to a multicast router internal to the PMIPv6 domain (or towards an additional MLD proxy node in the domain), for all the multicast channels (which, in consequence, have to be local). There should be direct connectivity between the MAG and the local multicast router (or additional MLD proxy). Zuniga, et al. Expires August 29, 2013 [Page 10] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MN MAG LMA MR | (MLD Proxy) (Unicast) (Multicast) MN attaches to MAG1 | | | | | | | |----Rtr Sol--------->| | | | |--PBU------->| | | | | | | |<-------PBA--| | | | | | | |===Unicast===| | | | Tunnel | | |<---------Rtr Adv----| | | | | | | |<--------Unicast Traffic---------->| | | | | | | | | | |<-------MLD Query----|<-------------MLD Query----| | | | | MN requires | | | multicast services | | | | | | | |--MLD Report (G)---->| | | | | | | | |----Aggregated------------>| | | MLD Report (G) | | | | | | | | | |<-------------Multicast Traffic----------------->| | | | | Figure 4: Multicast service establishment for direct routing Upon detecting node attachment from an incoming interface, the MAG adds each downstream interface to the MLD Proxy instance with upstream link to an MR according to the standard MLD proxy operations [RFC3810] and sends an MLD Query message towards the MN. The MN sends the MLD report message (when required by its upper layer applications) in response to an MLD Query from MAG. Upon receiving the MLD Report message from each incoming interface, the MAG checks the MLD Proxy instance associated with the downstream interface and then the MLD Report messages will be aggregated and forwarded to the upstream link associated with the MR (assuming that this is a new multicast group which the MAG had not previously subscribed to). Multicast traffic will then flow from the local multicast router towards the MN. Zuniga, et al. Expires August 29, 2013 [Page 11] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MN P-MAG N-MAG LMA MR | | | | | | | | | | |<------------|<-- Multicast Data----------------| | | . | | | | | . | | | | | . | | | Link Handover | | | Disconnected Detection | | | | | | | | | | | | | | | MN Attachment | | | | | | | | | | | | |----Rtr Sol------------->| | | | | | | | | | |--PBU----->| | | | | | | | | |<-----PBA--| | | | | | | |<-----------MLD Query----| | | | | | | | |----MLD Report---------->| | | | | | | | | | |----Aggregated------->| | | | MLD Report | | | | | | |<------------------------|<---Multicast Data----| | | | | | Figure 5: Multicast mobility signaling for direct routing Figure 5 shows the handover operation procedure for the direct routing operation mode. When an MN hands off to the next MAG (N-MAG) from the previous MAG (P-MAG), the N-MAG detects the newly arrived attached MN and performs binding update procedure by exchanging PBU/ PBA signaling messages with LMA. At the same time, a MLD Proxy instance detecting the new MN transmits an MLD query message to the MN. After receiving the MLD query message, the MN sends an MLD report message that includes the multicast group information. The N-MAG then sends an aggregated MLD report message to the upstream link associated with the MR. In the direct routing case, an upstream interface of MLD Proxy instance is decided towards certain multicast router based on the operator's configuration or multicast routing, as compared to the base solution defined in [RFC6224] where it is determined for each MN based on the Proxy Binding Update List. When the N-MAG receives the multicast packets from the MR, it then simply forwards them without tunnel encapsulation. The N-MAG updates the Zuniga, et al. Expires August 29, 2013 [Page 12] Internet-Draft Multicast Mobility Routing Optimizations February 2013 MN's location information to the LMA by exchanging PBU/PBA signaling messages. 5. Local Mobility Anchor Operation This section includes a new mobility option to support dynamic policies on subscription via MTMA/direct routing based on the local mobility anchor conveying the required info to the mobile access gateway in the proxy binding acknowledge message. 5.1. Dynamic IP Multicast Selector Option 5.1.1. Option application rules A new TLV-encoded mobility option, "Dynamic IP Multicast Selector" option is defined for use with the PBA (Proxy Binding Acknowledge) message exchanged between an LMA and a MAG to convey dynamic policies on subscription via MTMA/direct routing. This option is used for exchanging the IP addresses of both the group subscribed to by the MN, and the source(s) delivering it, as well as the applicable filter mode. This information is carried by using directly the Multicast Address Record format defined in [RFC3810]. There can be multiple "Dynamic IP Multicast Selector" options present in the message, one for each active subscription maintained by the MN (i.e., one per Multicast Address Record). 5.1.2. Option format The format of this new option is as follows: 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 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |M| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Multicast Address Record + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: To be defined by IANA. Zuniga, et al. Expires August 29, 2013 [Page 13] Internet-Draft Multicast Mobility Routing Optimizations February 2013 Length: 8-bit unsigned integer indicating the length of the option in octects, excluding the type and length fields. Reserved: This field is unused for now. The value MUST be initialized to 0 by the sender and MUST be ignored by the receiver. Dynamic IP Multicast Selector Mode Flag: This field indicates the subscription via MTMA/direct routing mode. If the (M) flag value is set to a value of (1), it is an indication that the IP multicast traffic associated to the multicast group identified by the Multicast Address Record in this mobility option SHOULD be routed locally (subscription via direct routing mode). If the (M) flag value is set to a value of (0), it is an indication that IP multicast traffic associated to the multicast group identified by the Multicast Address Record in this mobility option SHOULD be routed to the home network, via the MTMA (subscription via MTMA mode). All other IP traffic associated with the mobile node SHOULD be managed according to a default policy configured at the PMIPv6 multicast domain. Multicast Address Record: Multicast subscription information corresponding to a single subscribed multicast address as defined in [RFC3810]. 6. Multicast Tree Mobility Anchor Operation The MTMA provides connectivity to the multicast infrastructure out of the PMIPv6 domain. The MTMA itself could either act as an additional MLD proxy (only in the case where all the connected MAGs act also as MLD proxies), reporting to a further node an aggregated view of the subscriptions in a PMIPv6 multicast domain; or it can act as a designated multicast router for all the MAGs in a PMIPv6 multicast domain. The MTMA will then request the multicast content on behalf of the MAGs (and MNs behind them). In addition, the MTMA will create and maintain the corresponding multicast forwarding states per each tunnel interface towards the MAGs. Whatever the role played, when the MAGs act as MLD proxy, the MTMA becomes the MLD querier of the MLD proxy instance located in each MAG. Zuniga, et al. Expires August 29, 2013 [Page 14] Internet-Draft Multicast Mobility Routing Optimizations February 2013 6.1. Conceptual Data Structures The MTMA does not directly interact with the MNs attached to any of the MAGs. The MTMA only manages the multicast groups subscribed per MAG on behalf of the MNs attached to it. Having this in mind, the relevant information to be stored in the MTMA should be the tunnel interface identifier (tunnel-if-id) of the bi-directional tunnel for multicast between the MTMA and every MAG (e.g., similar to what it is stated in [RFC5213] for the unicast case), the IP addresses of the multicast group delivered per tunnel to each of the MAGs, and the IP addresses of the sources injecting the multicast traffic per tunnel to the multicast domain defined by the MTMA. 7. Mobile Node Operation The MN operation is not impacted by the existence of an MTMA as anchor for the multicast traffic being subscribed or the use of direct routing. The MN will act according to the stated operations in [RFC5213] and [RFC6224]. This draft considers that every MN requesting multicast-only services is previously registered in a PMIPv6 unicast domain to get a unicast IP address. The registration can also be required also for several purposes such as remote management, billing, multicast configuration, etc. A given mobile node's policy profile information must be updated to be able to store the IPv6 addresses of both the LMA and MTMA, the later for the subscription via MTMA case. 8. IPv4 support This document does not introduce any IPv4-specific issue. IPv4 and dual-stack IPv4/IPv6 considerations covered in section 4.4 of [RFC6224] also apply to the extensions defined in this document. Although references to "MLD proxy" have been used in the document, it should be understood to also include "IGMP/MLD proxy" functionality. 9. IANA Considerations TBD. Zuniga, et al. Expires August 29, 2013 [Page 15] Internet-Draft Multicast Mobility Routing Optimizations February 2013 10. Security Considerations This draft discusses the operations of existing protocols without modifications. It does not introduce new security threats beyond the current security considerations of PMIPv6 [RFC5213], MLD [RFC3810], IGMP [RFC3376] and IGMP/MLD Proxying [RFC4605]. 11. Authors Additional co-authors of this document are: Akbar Rahman InterDigital Communications, LLC E-mail: akbar.rahman@interdigital.com Ignacio Soto Universidad Carlos III de Madrid E-mail: isoto@it.uc3m.es 12. References 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, October 2002. [RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. [RFC4065] Kempf, J., "Instructions for Seamoby and Experimental Mobility Protocol IANA Allocations", RFC 4065, July 2005. [RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas, "Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)", RFC 4601, August 2006. [RFC4605] Fenner, B., He, H., Haberman, B., and H. Sandick, "Internet Group Management Protocol (IGMP) / Multicast Zuniga, et al. Expires August 29, 2013 [Page 16] Internet-Draft Multicast Mobility Routing Optimizations February 2013 Listener Discovery (MLD)-Based Multicast Forwarding ("IGMP/MLD Proxying")", RFC 4605, August 2006. [RFC4607] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, August 2006. [RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K., and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008. [RFC5847] Devarapalli, V., Koodli, R., Lim, H., Kant, N., Krishnan, S., and J. Laganier, "Heartbeat Mechanism for Proxy Mobile IPv6", RFC 5847, June 2010. [RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support in IPv6", RFC 6275, July 2011. 12.2. Informative References [I-D.asaeda-pim-mldproxy-multif] Asaeda, H. and S. Jeon, "Multiple Upstream Interface Support for IGMP/MLD Proxy", draft-asaeda-pim-mldproxy-multif-01 (work in progress), February 2013. [I-D.contreras-multimob-multiple-upstreams] Contreras, L. and C. Bernardos, "Extension of the MLD proxy functionality to support multiple upstream interfaces", draft-contreras-multimob-multiple-upstreams-00 (work in progress), October 2012. [I-D.deng-multimob-pmip6-requirement] Deng, H., Chen, G., Schmidt, T., Seite, P., and P. Yang, "Multicast Support Requirements for Proxy Mobile IPv6", draft-deng-multimob-pmip6-requirement-02 (work in progress), July 2009. [I-D.ietf-multimob-pmipv6-source] Schmidt, T., Gao, S., Zhang, H., and M. Waehlisch, "Mobile Multicast Sender Support in Proxy Mobile IPv6 (PMIPv6) Domains", draft-ietf-multimob-pmipv6-source-02 (work in progress), October 2012. [RFC6224] Schmidt, T., Waehlisch, M., and S. Krishnan, "Base Deployment for Multicast Listener Support in Proxy Mobile IPv6 (PMIPv6) Domains", RFC 6224, April 2011. Zuniga, et al. Expires August 29, 2013 [Page 17] Internet-Draft Multicast Mobility Routing Optimizations February 2013 Appendix A. MTMA Deployment Use Cases From the network architecture point of view, there are several options when considering the multicast tree mobility anchor (MTMA) approach. These options can be distinguished in terms of the number of LMAs and MTMAs present in a PMIPv6 domain and the service relationship that a set of MNs gets from them, in the form of a "LMA : MTMA" ratio. According to that, it is possible to differentiate the following approaches: o A set of MNs is served in a PMIPv6 domain by two entities, one MTMA for multicast service, and one LMA for unicast, in such a way that the ratio is 1:1 (one common PMIPv6 unicast and multicast domain). o A set of MNs is served in a PMIPv6 domain by several entities, one MTMA for multicast service, while the others (LMAs) for unicast, in such a way that the ratio is N:1 (N PMIPv6 unicast domains coexist with a unique multicast domain). o A set of MNs is served in a PMIPv6 domain by several entities, one LMA for unicast, while the others (MTMAs) are devoted to multicast service, in such a way that the ratio is 1:N (one single PMIPv6 unicast domain coexists with multiple multicast domains). Scenarios with an N:M ratio are considered to be a combination of the previous ones. A.1. PMIPv6 domain with ratio 1:1 This approach basically refers to the architecture presented in Figure 1. Within this approach, a common set of MNs is served by a couple of entities, one LMA for unicast and one MTMA for multicast. All the MNs of the set are served by these two elements as they move in the PMIPv6 domain. A.2. PMIPv6 domain with ratio N:1 This approach basically refers to the situation where a common set of MNs is served by a unique MTMA for multicast service, but simultaneously there are subsets from that group of MNs which are served by distinct LMAs for unicast service as they move in the PMIPv6 domain. Each particular MN association with the LMAs (unicast) and MTMA (multicast) remains always the same as it moves in the PMIPv6 domain. Figure 6 shows the scenario here described. Zuniga, et al. Expires August 29, 2013 [Page 18] Internet-Draft Multicast Mobility Routing Optimizations February 2013 +----------------+ +----------------+ |Content Source A| |Content Source B| +----------------+ +----------------+ | | | | *** *** *** *** *** *** *** *** *** *** *** * ** ** ** ** ** ** ** ** ** ** * * * * Fixed Internet * * (Unicast & Multicast Traffic) * * ** ** ** ** ** ** ** ** ** ** * *** *** *** *** *** *** *** *** *** *** *** | | | | | | | | | +------+ +-----------------+ +------+ | LMA1 | | MTMA2 | | LMA3 | +------+ +-----------------+ +------+ || \\ oo oo oo oo // || || \\ oo oo oo oo // || || \\ oo oo oo oo // || || \\ oo oo oo oo // || || \\oo oo oo oo // || || \\ oo oo oo// || || oo\\ oo oo // || || oo \\ oo oo //oo || || oo \\ oo oo // oo || || oo \\ oo oo // oo || +------+ +--------+ +--------+ +--------+ | MAG1 | | MAG2 | | MAG3 | | MAG4 | +------+ +--------+ +--------+ +--------+ | | | | | | | | | | | | | | | | {MN10} {MN11} {MN20} {MN21} {MN30} {MN31} {MN40} {MN41} Figure 6: PMIPv6 domain with ratio N:1 The Figure 6 proposes an architecture where there are two entities acting as LMAs, LMA1 and LMA3, while there is another one, named MTMA2, working as multicast tree mobility anchor. LMA1 and LMA3 constitute two distinct unicast domains, whereas MTMA2 forms a single multicast domain. The tunnels among MAGs and LMAs represented by lines ("||") indicate a tunnel transporting unicast traffic, while the tunnels among MAGs and MTMA2 depicted with circles ("o") show a tunnel transporting multicast traffic. In the figure it can be observed that all the MNs are served by MTMA2 for the incoming multicast traffic from sources A or B. However, Zuniga, et al. Expires August 29, 2013 [Page 19] Internet-Draft Multicast Mobility Routing Optimizations February 2013 there are different subsets regarding unicast traffic which maintain distinct associations within the PMIPv6 domain. For instance, the subset formed by MN10, MN11, MN20 and MN21 is served by LMA1 for unicast, and the rest of MNs are being served by LMA3. For the scenario described above, the association between each MN and the corresponding LMA and MTMA is permanently maintained. A.3. PMIPv6 domain with ratio 1:N This approach is related to a scenario where a common group of MNs is served by a unique LMA for unicast service, but simultaneously there are subsets from that group of MNs which are served by distinct MTMAs for multicast service as they move in the PMIPv6 domain. Different MTMAs might be associated to serving different multicast groups. These associations remain the same even if the MNs move moves within the PMIPv6 domain. Figure 7 shows the scenario here described. Zuniga, et al. Expires August 29, 2013 [Page 20] Internet-Draft Multicast Mobility Routing Optimizations February 2013 +----------------+ +----------------+ |Content Source A| |Content Source B| +----------------+ +----------------+ | | | | *** *** *** *** *** *** *** *** *** *** *** * ** ** ** ** ** ** ** ** ** ** * * * * Fixed Internet * * (Unicast & Multicast Traffic) * * ** ** ** ** ** ** ** ** ** ** * *** *** *** *** *** *** *** *** *** *** *** | | | | | | | | | +------+ +-----------------+ +------+ | MTMA1| | LMA2 | | MTMA3| +------+ +-----------------+ +------+ oo oo // || || \\ oo oo oo oo // || || \\ oo oo oo oo // || || \\ oo oo oo oo // || || \\ oo oo oo oo// || || \\ oo oo oo oo || || \\oo oo oo //oo || || \\ oo oo // oo || || oo\\ oo oo // oo || || oo \\ oo oo // oo || || oo \\ oo +------+ +--------+ +--------+ +--------+ | MAG1 | | MAG2 | | MAG3 | | MAG4 | +------+ +--------+ +--------+ +--------+ | | | | | | | | | | | | | | | | {MN10} {MN11} {MN20} {MN21} {MN30} {MN31} {MN40} {MN41} Figure 7: PMIPv6 domain with ratio 1:N The Figure 7 proposes an architecture where the LMA2 is the unique LMA for a certain group of MNs, while there are two others entities, MTMA1 and MTMA3, acting as MTMAs for different subsets of MNs of the same group. MTMA1 and MTMA3 constitute two distinct multicast domains, whereas LMA2 forms a single unicast domain. Each MTMA could be devoted to carry on a different content (for instance, MTMA1 for source A and MTMA3 for source B). Looking at the picture, the subset formed by MN10, MN11, MN20 and MN21 is served by MTMA1 for multicast. The rest of MNs are being served by MTMA3 also for multicast. Finally, all of them are served by LMA2 for unicast. For the scenario described above, the association between multicast content Zuniga, et al. Expires August 29, 2013 [Page 21] Internet-Draft Multicast Mobility Routing Optimizations February 2013 and MTMA is permanently maintained. A.4. PMIPv6 domain with H-LMA The H-LMA is defined as an entity which simultaneously transports unicast and multicast service, that is, it simultaneously works as LMA and MTMA. In the context of the MTMA solution, an H-LMA can play the role of MTMA for an entire group of MNs in a PMIPv6 domain, while acting simultaneously as LMA for a subset of them. The figure 9 adapts the PMIPv6 domain with ratio N:1 scenario of figure 7 to the case where MTMA2 is an H-LMA, which serves multicast traffic to all the MNs in the picture, and simultaneously, it is able to serve unicast traffic to the subset formed by MN30, MN40 and MN41. Zuniga, et al. Expires August 29, 2013 [Page 22] Internet-Draft Multicast Mobility Routing Optimizations February 2013 +----------------+ +----------------+ |Content Source A| |Content Source B| +----------------+ +----------------+ | | | | *** *** *** *** *** *** *** *** *** *** *** * ** ** ** ** ** ** ** ** ** ** * * * * Fixed Internet * * (Unicast & Multicast Traffic) * * ** ** ** ** ** ** ** ** ** ** * *** *** *** *** *** *** *** *** *** *** *** | | | | | | | | | +------+ +-----------------+ +------+ | LMA1 | | H-LMA | | LMA3 | +------+ +-----------------+ +------+ || \\ oo db db oo // || || \\ oo db db oo // || || \\ oo db db oo // || || \\ oo db db oo // || || \\oo db db oo // || || \\ db db oo// || || oo\\ db db // || || oo \\ db db //oo || || oo \\ db db // oo || || oo \\ db db // oo || +------+ +--------+ +--------+ +--------+ | MAG1 | | MAG2 | | MAG3 | | MAG4 | +------+ +--------+ +--------+ +--------+ | | | | | | | | | | | | | | | | {MN10} {MN11} {MN20} {MN21} {MN30} {MN31} {MN40} {MN41} Figure 8: PMIPv6 domain with H-LMA Figure 7 presents a PMIPv6 network where there are two pure unicast LMAs, LMA1 and LMA3, and a hybrid LMA, labeled as H-LMA in the figure. The H-LMA is an MTMA from the perspective of MAG1 and MAG4. The tunnels among MAGs and LMAs represented by lines ("||") indicate a tunnel transporting exclusively unicast traffic, the tunnels depicted with circles ("o") show a tunnel transporting exclusively multicast traffic, and the tunnels with mixed lines and circles ("db") describe a tunnel transporting both types of traffic simultaneously. Zuniga, et al. Expires August 29, 2013 [Page 23] Internet-Draft Multicast Mobility Routing Optimizations February 2013 All of the MNs in the figure receive the multicast traffic from H-LMA (one single multicast domain), but it is possible to distinguish three subsets from the unicast service perspective (that is, three unicast domains). The first subset is the one formed by MN10, MN11 and MN 20, which receives unicast traffic from LMA1. A second subset is the one formed by MN21 and MN30, which receives unicast traffic from H-LMA. And finally, a third subset is built on MN31, MN40 and MN41, which receives unicast traffic from LMA3. For the scenario described above, the association between each MN and the corresponding LMA and H-LMA is permanently maintained. Authors' Addresses Juan Carlos Zuniga InterDigital Communications, LLC 1000 Sherbrooke Street West, 10th floor Montreal, Quebec H3A 3G4 Canada Email: JuanCarlos.Zuniga@InterDigital.com URI: http://www.InterDigital.com/ Luis M. Contreras Telefonica I+D Don Ramon de la Cruz, 82-84 Madrid 28006 Spain Email: lmcm@tid.es Carlos J. Bernardos Universidad Carlos III de Madrid Av. Universidad, 30 Leganes, Madrid 28911 Spain Phone: +34 91624 6236 Email: cjbc@it.uc3m.es URI: http://www.it.uc3m.es/cjbc/ Zuniga, et al. Expires August 29, 2013 [Page 24] Internet-Draft Multicast Mobility Routing Optimizations February 2013 Seil Jeon Instituto de Telecomunicacoes Campus Universitario de Santiago Aveiro 3810-193 Portugal Email: seiljeon@av.it.pt URI: https://atnog.av.it.pt/~sjeon/ Younghan Kim Soongsil University Sangdo-dong, Dongjak-gu Seoul 511 Republic of Korea Email: yhkim@dcn.ssu.ac.kr URI: http://dcnlab.ssu.ac.kr/ Zuniga, et al. Expires August 29, 2013 [Page 25]