Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) Servers
RFC 3319
Document | Type |
RFC - Proposed Standard
(July 2003; No errata)
Was draft-ietf-sip-dhcpv6 (sip WG)
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Authors | Bernie Volz , Henning Schulzrinne | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3319 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Allison Mankin | ||
IESG note |
Comments sent to authors - 01 received and dhcpv6 to advance - checking fixes with Discussants [Note from Allison] |
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Send notices to | <rohan@cisco.com> |
Network Working Group H. Schulzrinne Request for Comments: 3319 Columbia University Category: Standards Track B. Volz Ericsson July 2003 Dynamic Host Configuration Protocol (DHCPv6) Options for Session Initiation Protocol (SIP) Servers Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document defines a Dynamic Host Configuration Protocol version 6 (DHCPv6) option that contains a list of domain names or IPv6 addresses that can be mapped to one or more Session Initiation Protocol (SIP) outbound proxy servers. This is one of the many methods that a SIP client can use to obtain the addresses of such a local SIP server. 1. Terminology This document uses the DHCP terminology defined in [1]. A SIP server is defined in RFC 3261 [2]. This server MUST be an outbound proxy server, as defined in [3]. In the context of this document, a SIP server refers to the host the outbound SIP proxy server is running on. A SIP client is defined in RFC 3261 [2]. The client can be a user agent client or the client portion of a proxy server. In the context of this document, a SIP client refers to the host the SIP client is running on. Schulzrinne & Volz Standards Track [Page 1] RFC 3319 DHCPv6 Options for SIP Servers July 2003 In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119 [4]. 2. Introduction The Session Initiation Protocol (SIP) [2] is an application-layer control protocol that can establish, modify and terminate multimedia sessions or calls. A SIP system has a number of logical components: user agents, proxy servers, redirect servers and registrars. User agents MAY contain SIP clients, proxy servers always do. This document specifies two DHCPv6 options [1] that allow SIP clients to locate a local SIP server that is to be used for all outbound SIP requests, a so-called outbound proxy server. (SIP clients MAY contact the address identified in the SIP URL directly, without involving a local SIP server. However in some circumstances, such as when firewalls are present, or local dialing plans, local emergency and other services need to be provided, SIP clients need to use a local server for outbound requests.) This is one of many possible solutions for locating the outbound SIP server; manual configuration is an example of another. 3. SIP Server DHCPv6 Option This document defines two DHCPv6 options that describe a local outbound SIP proxy: one carries a list of domain names (Section 3.1), the other a list of 128-bit (binary) IPv6 addresses (Section 3.2). Since DHCPv6 does not suffer from a shortage of option codes, we avoid the encoding byte found in the IPv4 DHCP option for SIP servers [6]. This makes the option shorter, easier to parse, simplifies appropriate word alignment for the numeric addresses and allows the client to request either numeric or domain name options using the "option request option". An implementation implementing this specification MUST support both options. 3.1 SIP Servers Domain Name List The option length is followed by a sequence of labels, encoded according to Section 3.1 of RFC 1035 [5], quoted below: "Domain names in messages are expressed in terms of a sequence of labels. Each label is represented as a one octet length field followed by that number of octets. Since every domain name ends Schulzrinne & Volz Standards Track [Page 2] RFC 3319 DHCPv6 Options for SIP Servers July 2003 with the null label of the root, a domain name is terminated by a length byte of zero. The high order two bits of every length octet must be zero, and the remaining six bits of the length field limit the label to 63 octets or less. To simplify implementations, the total length of a domain name (i.e., label octets and label length octets) is restricted to 255 octets or less." RFC 1035 encoding was chosen to accommodate future internationalized domain name mechanisms.Show full document text