INTERNET-DRAFT Ramakanth Josyula Intended Status: Proposed Standard Brocade Communications Expires: April 05, 2014 October 02, 2013 DHCP Option for IPTV Source address draft-josyula-dhc-multicast-02.txt Abstract Internet Protocol Television(IPTV) is a system facilitating transmission of television channels as multicast streams use dedicated multicast group addresses in IP networks. Internet Group Multicast Protocol(IGMP) is widely used for the communication between hosts and routers to deliver the multicast streams in the IPv4 networks. Similarly,Multicast Listener Discovery Protocol (MLD)is used for the communication between the hosts and routers to deliver the multicast streams in the IPv6 networks. It is also possible for the networks to distinguish these multicast streams not only by their destination multicast group but also by the source IP address of the streams. IGMP version-3 and MLD version-2 are protocols that allow the hosts to inform the neighboring routers about their desire to receive the multicast streams from specific source IP addresses. This needs a mechanism to supply the available multicast source address information to the hosts and the hosts also should be strictly implemented with the source specific multicasting aware protocols such as above mentioned IGMPv3 or MLDv2. This document describes a new DHCP option which can addresses these issues. In addition to this, the document also describes about the advantages in the networks by implementing this option. Status of this Memo This Internet-Draft is submitted to IETF 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. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Expires March 26, 2014 [Page 1] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Copyright and License Notice Copyright (c) 2013 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 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 1.1 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Background . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 Topology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.2 Network behavior . . . . . . . . . . . . . . . . . . . 4 1.2.3 Limitations . . . . . . . . . . . . . . . . . . . . . . 4 2. DHCP IPTV Source Address Option . . . . . . . . . . . . . . . . 4 2.1 DHCP IPTV Source Address Option in IPv4 . . . . . . . . . . 4 2.2 DHCP IPTV Source Address Option in IPv6 . . . . . . . . . . 5 3 Server and client behavior . . . . . . . . . . . . . . . . . . 5 4 Advantages . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5 Security Considerations . . . . . . . . . . . . . . . . . . . . 7 6 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 7 References . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7.1 Normative References . . . . . . . . . . . . . . . . . . . 7 7.2 Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Expires March 26, 2014 [Page 2] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 1 Introduction 1.1 Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 1.2 Background Many broad band service providers all across the world are delivering triple play or multi play solutions. IPTV Solution is widely integrated as part of these solutions.In many cases this service is run by delivering multicast streams to the IP hosts/Set top boxes connected to the home gateways. IGMP protocol in IPv4 networks and MLD protocol in IPv6 networks are commonly used for requesting these multicast streams from the nearest router connected via an access network. Below sections will explain the typical topology and functionality in most of the traditional access networks. The MLD protocol follows the same mechanism in IPv6 networks of IGMP in IPv4. In-order to reduce the complexity, the rest of the discussion in the document is made with reference to IGMP only. MLD specific issues are quoted wherever it is required. Further, wherever IGMP version-3 is referred, it is implied that can pointed to the MLD version-2 in IPv6 networks. 1.2.1 Topology +---------------+ | Aggregation| | |-----Modem1/HomeGW-- Host-|- Host A LAN | | Access | Lan |- Host B | | Node-1 | |- Host C |-----| |-- | | | |... +---------+ | +---------------+ | DHCP |--| | Server | | +---------+ | | | +---------------+ +---------+ | | |----- Modem2/----- Host D | Layer-3 | | | Access | HomeGW | Switch |--|-----| Node-2 | | OR | | | |----- Modem3/----- Host E | Router | | | |... HomeGW | | +---------------+ +---------+ Figure 1: Triple play soution access network Expires March 26, 2014 [Page 3] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 1.2.2 Network behavior When any of the hosts starts(eg.power-on)initially, it will do a DHCP discover/request to get an IP address to interact with the network. DHCP server in the network will assign a unicast IP address to the host. The nearest router will be sending IGMP general query messages for every query interval time to check if any of the hosts are interested in multicast service. If the host is interested in receipt of a multicast channel, it will send an IGMP membership report message towards the router. The router will forward the multicast streams destined to the requested multicast group towards the user interface. When the IGMP version-3 is implemented in the network, the user will send the IGMP report message to include or exclude particular multicast sources from the network. Router will forward the multicast streams ONLY from the sources requested by the user. 1.2.3 Limitations For the implementation IGMPv3 or for upgrading the networks to IGMPv3, the below additional requirements are to be met by the network elements: 1. The network should build a mechanism that supplies the multicast source address information to the hosts. 2. The hosts should be capable of distinguishing the multicast streams based on the source IP address from which they are originated. 3. The hosts should strictly follow IGMP version-3 mechanism for exchanging IGMP messages with the network elements. The new option described in the below sections can effectively address these issues. 2. DHCP IPTV Source Address Option The "IPTV Source Address" option specifies a list of IPTV source IP addresses available or accessible to the hosts for receiving the multicast streams. These source IPs can be listed in the option in the order of any criteria such as quality of service or specific service level agreements (SLAs)etc. 2.1 DHCP IPTV Source Address Option in IPv4 Below figure shows the option format: Expires March 26, 2014 [Page 4] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 Code Len Address 1 Address 2 +-----+-----+-----+-----+-----+-----+-----+-----+-- | TBD | n | a1 | a2 | a3 | a4 | a1 | a2 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-- The minimum length of the option is 4 bytes. The length of the option should be in the multiples of 4. 2.2 DHCP IPTV Source Address Option in IPv6 Below figure show the option format: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | (option code)TBD | option-len(n) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IP Address-1 | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | IP Address-2 | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The minimum length of this option would be 16Bytes and the length of the option would be in the multiples of 16. 3 Server and client behavior In case of IPv4 networks, the defined "IPTV Source Address option" field will be filled by the DHCP server while sending the DHCP acknowledgement packet to the client. Client can also send a DHCP inform message to the DHCP server, requesting this parameter. Similarly, incase of IPv6 networks, this option can be included in the DHCP solicit, advertise, request, renew, rebind, Information- request and reply. The clients can also request this option by including this in the Options Request Option(ORO). Expires March 26, 2014 [Page 5] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 The server will be pre-configured by the multicast source address information by the administrator as per the SLA/policy or any such criteria specific to the multicast users. The clients will use the source addresses obtained from the server while interacting with the routers using IGMPv3 or MLDv2. If the hosts are still using older versions of IGMP/MLD protocols which are not capable of requesting or distinguishing the multicast traffic based on the source IP address, this is also possible that the intermediate access nodes can snoop the DHCP messages and keep the record of the list of source addresses provided to the host. By using this information, the access nodes can filter the multicast streams on behalf of the hosts. This snooping information can also be used to authenticate the users for accessing the multicast service from various multicast sources in the network. 4 Advantages By addressing the issues mentioned in the section 1.1.3, the implementation of this option in the network provides various advantages to the network. - It provides an effective method for maintaining and updating the multicast source address information to every multicast host in the network as per their individual SLAs. - Intermediate access nodes can snoop this option from the DHCP messages to extend the its multicast services like : - Forwarding the multicast streams only to the authorized users - Acting on behalf of the older clients which are non source aware protocol versions (like IGMPv1/v2 and MLDv1) and make them integrated with the latest source specific multicast networks with IGMPv3/MLDv2 implementations. - Convergence of IPTV services from different users can be achieved at the user level irrespective of the multicast transmitting technologies used in the network.For example,any service provider who manages the aggregation and access networks can receive the multicast streams from different sources/networks (may not be under their own administration) and feed them to their access networks. - The subscribers can easily validate the quality of the service offered by different IPTV sources dynamically and switch to the interested source as per their own set of requirements. Expires March 26, 2014 [Page 6] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 5 Security Considerations All the security considerations mentioned in rfc2131 (Dynamic Host Control Protocol) are applicable for this document.If any malpractice or mal function in DHCP may effect further transmission of multicast traffic in the network. 6 IANA Considerations IANA is requested to assign the option for multicast source address for the registry maintained for DHCP. 7 References 7.1 Normative References [RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A. Thyagarajan, "Internet Group Management Protocol, Version 3", RFC 3376, October 2002. [RFC2236] Fenner, W., "Internet Group Management Protocol, Version 2", RFC 2236, November 1997. [RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5, RFC 1112, August 1989. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor Extensions", RFC 2132, March 1997. [RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1340, July 1992 [SSM] Holbrook, H. and B. Cain, "Source-Specific Multicast for IP", RFC 4607, August 2006. [MLDv2] Vida, R. and L. Costa, "Multicast Listener Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004. [RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast Listener Discovery (MLD) for IPv6", RFC 2710, October 1999. Expires March 26, 2014 [Page 7] INTERNET DRAFT DHCP Option for IPTV Source address October 03, 2013 7.2 Informative References Authors' Addresses Ramakanth Josyula, Brocade Communications Systems Pvt Ltd, Vrindavan Tech Village - Special Economic Zone, Devarabeesanahall Village, Varthur Hobli, Bangalore, India - 560037 Phone: +91 9591631444 EMail: josyular@brocade.com;ramakanthjosyula@gmail.com; Expires March 26, 2014 [Page 8]