Network Working Group K. Chowdhury Internet-Draft Nortel Networks Expires: February 15, 2005 P. Yegani Cisco Systems L. Madour Ericsson August 17, 2004 DHCPv4 Options for Broadcast and Multicast Control Servers draft-chowdhury-dhc-bcmcv4-option-01.txt Status of this Memo By submitting this Internet-Draft, I certify that any applicable patent or other IPR claims of which I am aware have been disclosed, and any of which I become aware will be disclosed, in accordance with RFC 3668. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 15, 2005. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document defines new options for Broadcast and Multicast Service controller discovery in an IP network. Broadcast service is being developed for 3G wireless networks. Users of the service interact with a controller in the network to derive informations that are required to receive broadcast service. Dynamic Host Configuration Protocol can be used to configure the controller IPv4 addresses or Chowdhury, et al. Expires February 15, 2005 [Page 1] Internet-Draft August 2004 fully qualified domain names in the user's devices. This document defines the related options and option codes. Table of Contents 1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Broadcast Service Controller Options . . . . . . . . . . . . . 6 4.1 Broadcast Service Controller Domain Name list . . . . . . 6 4.2 Broadcast Service Controller IPv4 address option . . . . . 7 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 8. Normative References . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 10 Intellectual Property and Copyright Statements . . . . . . . . 12 Chowdhury, et al. Expires February 15, 2005 [Page 2] Internet-Draft August 2004 1. Motivation Dynamic Host Configuration Protocol can be used to configure various non-IP address type of parameters. These parameters are required for normal operation of various services that are offered over an IP network. In 3G wirelesss network standards body such as 3GPP2 (www.3gpp2.org), broadcast and multicast service is being developed [BCMCS]. The service includes a controller component that is responsible for managing the service via interaction with the users and other network entities. The users of the service are required to know the IPv4 address of the controller entity so that they can download all the necessary information about a desired broadcast program. In a roaming environment static configuration of the controller IPv4 address becomes unrealistic. Therefore, DHC is considered to be a method to dynamically configure controller IPv4 address or the fully qualified domain name of the controller in the 3G wireless networks. In order to allow the users to discover the broadcast controllers, the clients need to request for appropriate option codes from the DHC servers using Option-Request-Option and the DHC servers need to return corresponding configuration options that carry the broadcast and multicast service controller IPv4 address or fully qualified domain name. The motivation for this document is to define the necessary options and option codes. Chowdhury, et al. Expires February 15, 2005 [Page 3] Internet-Draft August 2004 2. Overview The Broadcast and Multicast Service architecture in a 3G wireless network such as 3GPP2 has the following model: +------------+ +--------+ | | | | | Controller | | DHCP | | | | Server | +------------+ +--------+ | Control| Info| | | V +----+ +------------+ +------------+ | | | | | | | MN/| bearer | Radio | | Broadcast | |User|<-------| Access |<---| Content | | | | Network | | Server | +----+ +------------+ +------------+ Note that this inforamtive figure is shown here for broad understanding of how Broadcast and Multicast service works in a 3G radio network. The network elements except MN/user and the DHCP server are not relevant to the text in this document. The user interacts with the Controller to request for broadcast/ multicast program information from the network (e.g., scheduled time, multicast IP address, port numbers). The User may also be authenticated by the Controller while downloading the relevant program security related information (such as encryption key). These interactions happen via HTTP and XML. For details of Broadcast and Multicast Service operation in 3GPP2, see [BCMCS]. There may be more than one controller in the network. The user should discover the appropriate controller to request the relevant program information. Chowdhury, et al. Expires February 15, 2005 [Page 4] Internet-Draft August 2004 3. Terminology The keywords "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. Chowdhury, et al. Expires February 15, 2005 [Page 5] Internet-Draft August 2004 4. Broadcast Service Controller Options This section defines the configuration option for the controller of Broadcast Service. The Configuration Option contains the IPv4 address or the fully qualified domain names of the broadcast service controller. 4.1 Broadcast Service Controller Domain Name list If the 'enc' byte has a value of 0, the encoding byte is followed by a sequence of labels, encoded according to Section 3.1 of RFC 1035 [RFC1035]. The option MAY contain multiple domain names, but these domain names SHOULD be used to construct SRV lookups as specified in [BCMCS], rather than querying for different A records. The client MUST try the records in the order listed, applying the mechanism described in [BCMCS] for each entry. The client only resolves the subsequent domain names if attempts to contact the first one failed or yielded no common transport protocols between the client and the controller or denote a domain administratively prohibited by cleint's policy. Use of multiple domain names is not meant to replace the SRV records, but rather to allow a single DHCP server to indicate the broadcast controllers in the access provider's network. Clients MUST support compression according to the encoding in Section 4.1.4 of "Domain Names - Implementation And Specification [RFC1035]. Since the domain names are supposed to be different domains, compression will likely have little effect, however. If the length of the domain list exceeds the maximum permissible within a single option (254 octets), then the domain list MUST be represented in the DHCP message as specified in [RFC3396] . The DHCP option for this encoding has the following format: Code Len enc FQDN(s) of Broadcast Controller +-----+-----+-----+-----+-----+-----+-----+-----+-- | TBD | n | 0 | s1 | s2 | s3 | s4 | s5 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-- An example case when two controller domain names e.g. bcmc1.carrier1.com, bcmc2.carrier1.com are returned will be: Chowdhury, et al. Expires February 15, 2005 [Page 6] Internet-Draft August 2004 +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |TBD|38 | 5 |'b'|'c'|'m'|'c'|'1'| 8 |'c'|'a'|'r'|'r'|'i'|'e'|'r'| +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ |'1'| 3 |'c'|'o'|'m'| 5 |'b'|'c'|'m'|'c'|'2'| 8 |'c'|'a'|'r'|'r'| +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+ |'i'|'e'|'r'|'1'| 3 |'c'|'o'|'m'| +---+---+---+---+---+---+---+---+ 4.2 Broadcast Service Controller IPv4 address option If the 'enc' byte has a value of 1, the encoding byte is followed by a list of IPv4 addresses indicating broadcast controller IPv4 addresses. The controllers MUST be listed in order of preference. Its minimum length is 5, and the length MUST be a multiple of 4 plus one. The DHCP option for this encoding has the following format: Code Len enc Address 1 Address 2 +-----+-----+-----+-----+-----+-----+-----+-----+-- | TBD | n | 1 | a1 | a2 | a3 | a4 | a1 | ... +-----+-----+-----+-----+-----+-----+-----+-----+-- Chowdhury, et al. Expires February 15, 2005 [Page 7] Internet-Draft August 2004 5. Security Considerations The security considerations in the base DHCPv6 spec [RFC2131] applies. An attacker may change information of the Broadcast Service Controller in packets that are in-tranist from DHCP server to the MN, if integrity protection is not in place. In that event, the user of the Broadcast service may be diverted to a rogue broadcast service controller. In the absence of a mutual authentication procedure between MN and the Broadcast controller, the MN may receive wrong or fraudulent information about Broadcast Service. Chowdhury, et al. Expires February 15, 2005 [Page 8] Internet-Draft August 2004 6. IANA Considerations The option codes for Broadcast Service Controller Domain Name list and the IPv4 address Must be assigned by IANA. Chowdhury, et al. Expires February 15, 2005 [Page 9] Internet-Draft August 2004 7. Acknowledgements Thanks to the follwoing indivduals for their review and constructive comments during the development of this document: AC Mahendran, Jun Wang, Raymond Hsu, Jayshree Bharatia, Ralph Dorms, Ted Lemon. 8 Normative References [BCMCS] 3GPP2, www.3gpp2.org, "X.P0022, Broadcast and Multicast Service in cdma2000 Wireless IP Network.", October 2003. [RFC1035] Mockapetris, P., "Domain names - implementation and specification", STD 13, RFC 1035, November 1987. [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March 1997. [RFC3396] Lemon, T. and S. Cheshire, "Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396, November 2002. Authors' Addresses Kuntal Chowdhury Nortel Networks 2221 Lakeside Blvd. Richardson, TX 75082 US Phone: +1 972-685-7788 EMail: chowdury@nortelnetworks.com Parviz Yegani Cisco Systems 3625 Cisco Way San Jose, CA 95134 US Phone: +1 408-832-5729 EMail: pyegani@cisco.com Chowdhury, et al. Expires February 15, 2005 [Page 10] Internet-Draft August 2004 Lila Madour Ericsson 8400, Decarie Blvd Town of Mount Royal, Quebec H4P 2N2 CANADA Phone: +1 514-345-7900 EMail: Lila.Madour@ericsson.com Chowdhury, et al. Expires February 15, 2005 [Page 11] Internet-Draft August 2004 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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