Network Working Group R.R. Chodorek Internet Draft AGH Univ. of Science and Technology Intended status: Standards Track February 7, 2017 Expires: August 7, 2017 Multiple multicast addressing architecture draft-chodorek-6man-multigroup-multicast-addr-04 Abstract This document introduces a new class of IPv6 multicast addresses called "multiple multicast". We define multiple multicast as a set of multicast addresses belonging to one multicast session. 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. 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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 ................................................ 2 2. Conventions used in this document ........................... 2 3. Multiple multicast addressing ............................... 3 4. Usage of multiple multicast addressing ...................... 3 4.1. Multimedia layered multicast ........................... 4 4.2. Multimedia conference systems .......................... 4 4.3. Multiple content from the one sender ................... 4 4.4. Routers ................................................ 4 5. Security Considerations ..................................... 4 6. IANA Considerations ......................................... 5 7. References .................................................. 5 7.1. Normative References ................................... 5 7.2. Informative References ................................. 5 1. Introduction Multimedia services can use multiple multicast streams [ITU2009] which form one multicast session. These services have been provided using several multicast groups or one multicast group and user level filtering. For services which have been provided using several multicast groups this document introduces the new class of IPv6 multicast addresses called "multiple multicast". We define a multiple multicast as a set of multicast addresses belonging to one multicast session. Multicast addresses which belong to the one multiple multicast address follow the same multicast tree. It allows for identical propagation parameters for each transmitted stream belonging to one multicast session. It also simplifies multicast routing and the management of multiple multicast streams. The new class of IPv6 multicast addresses expands the current IPv6 multicast addressing architecture [RFC4291]. 2. 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 [RFC2119]. Chodorek Expires August 7, 2017 [Page 2] Internet-Draft Multiple multicast addressing February 2017 3. Multiple multicast addressing The new class of IPv6 multicast addresses expands the unicast- prefix-based IPv6 multicast address [RFC7371][RFC3306]. The group ID is divided into two fields (Figure 1). The first one is session ID (20 bits). The second one is stream ID (12 bits). | 8 | 4 | 4 | 4 | 4 | 8 | 64 | 20 | 12 | +--------+----+----+----+----+------+---------+---------+--------+ |11111111|ff1 |scop|ff2 |rsvd| plen | network | session | stream | | | | | | | | prefix | ID | ID | +--------+----+----+----+----+------+---------+---------+--------+ Figure 1 New class of IPv6 multicast address +-+-+-+-+ ff2 (flag field 2) is a set of 4 flags: |r|r|G|r| +-+-+-+-+ where: o "r" bits is for future assignment and MUST each be set to 0, o G = 1 indicates a multigroup multicast address. The new class of IPv6 addresses will be indicated by bit G in the ff2 (flag field 2). If a new multicast session is created a new session ID is generated. If within the specified session a new stream is required then a new stream ID is generated. A value of 0 is reserved for the field session ID. There is also a value of 0 reserved for the field stream ID. 4. Usage of multiple multicast addressing There are two main benefits to using multiple multicast addressing: multimedia layered multicast (hierarchical coding) and multimedia conference systems [ITU2009]. It is also possible to use the proposed addressing scheme in large multicast multimedia streaming services. This addressing scheme simplifies multicast routing and the management of multiple multicast streams. Chodorek Expires August 7, 2017 [Page 3] Internet-Draft Multiple multicast addressing February 2017 4.1. Multimedia layered multicast A multimedia layered multicast hierarchically encodes multimedia content into complementary layers and these are transmitted through the network as separate multicast groups. Using the new addressing scheme if a sender wants to send a layered multicast to recipients they must first allocate a new session ID for all streams (layers). Each layer is allocated a new stream ID. In a typical allocation scheme for layered transmission the base layer will have the stream ID set to a value of 1. 4.2. Multimedia conference systems For the multimedia content of a conference two (audio, video) or more (audio, video and additional data) multicast streams will be created. Each of the conference participants will have one session ID created and for each stream a stream ID is allocated. Typically: base audio stream ID = 1, video stream ID = 2 and additional data will have stream IDs with higher numbers. 4.3. Multiple content from the one sender One IPTV service platform operator can sends multiple TV streams (e.g. different TV channels or two or more channels that offer the same content but in different resolutions and/or formats). In IPTV SSM multicast is desired. According to [RFC 3306] the SSM address sets plen = 0 and sets network prefix = 0. In the proposed addressing scheme for all transmitted content the service provider allocates the session ID. For each TV stream the service provider allocates one or more stream IDs. 4.4. Routers Routers must recognize multiple multicast addressing. For each session ID the router builds one common delivery tree (common multicast delivery tree is essential to provide multicast-based congestion avoidance [Cho2004]). If a user wants to receive a new stream with a selected stream ID the router must enable forwarding for it. If a user does not need a specified stream the router must disable the stream for the specified stream ID. 5. Security Considerations The same security considerations as those discussed in [RFC3306] are to be taken into account. Chodorek Expires August 7, 2017 [Page 4] Internet-Draft Multiple multicast addressing February 2017 6. IANA Considerations This document does not require any action from IANA. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3306] Haberman, B. and D. Thaler, "Unicast-Prefix-based IPv6 Multicast Addresses", RFC 3306, August 2002. [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006. [RFC7371] Boucadair, M., and Venaas, S., "Updates to the IPv6 Multicast Addressing Architecture", RFC 7371, September 2014. 7.2. Informative References [ITU2009] ITU-T, "Multicast functions in next generation networks", ITU-T Recommendation Y.2017, 2009. [Cho2004] Chodorek, A., and Chodorek, R.R., "Multigroup Communication Using Active Networks Technology", 3rd International Conference on Network Control and Engineering for QoS, Security and Mobility (Net-Con 2004), pp. 315-326, 2004. Authors' Addresses Robert R. Chodorek AGH Univ. of Science and Technology Al. Mickiewicza 30 30-059 Krakow Poland Email: chodorek@agh.edu.pl Chodorek Expires August 7, 2017 [Page 5]