Session Initiation Protocol Extension Header Field for Registering Non-Adjacent Contacts
RFC 3327, “Session Initiation Protocol Extension Header Field for Registering Non-Adjacent Contacts”, is a Proposed Standard document published in December 2002 by D. Willis, B. Hoeneisen. It has since been updated by RFC 5626. The canonical text is published by the RFC Editor.
Abstract
The REGISTER function is used in a SIP system primarily to associate a temporary contact address with an address-of-record. This contact is generally in the form of a URI, such as Contact: <sip:alice@pc33.atlanta.com> and is generally dynamic and associated with the IP address or hostname of the SIP UA. The problem is that network topology may have one or more SIP proxies between the UA and the registrar, such that any request travelling from the user's home network to the registered UA must traverse these proxies. The REGISTER method does not give us a mechanism to discover and record this sequence of proxies in the registrar for future use. This document defines an extension header field, 'Path' which provides such a mechanism
What “Proposed Standard” means
An entry-level standards-track specification: stable, peer-reviewed and a solid basis for implementation, though it may still evolve before becoming an Internet Standard.
The canonical text of RFC 3327 is hosted at rfc-editor.org. Available in TXT,HTML.
- RFC 3326 The Reason Header Field for the Session Initiation Protocol
- RFC 3325 Private Extensions to the Session Initiation Protocol for Asserted Identity within Trusted Networks
- RFC 3330 Special-Use IPv4 Addresses
- RFC 3324 Short Term Requirements for Network Asserted Identity
- RFC 3331 Signaling System 7 Message Transfer Part 2 - User Adaptation Layer
- RFC 3323 A Privacy Mechanism for the Session Initiation Protocol
- RFC 3332 Signaling System 7 Message Transfer Part 3 - User Adaptation Layer
- RFC 3334 Policy-Based Accounting