Internet Engineering Task Force (IETF) H. Schulzrinne
Request for Comments: 5971 Columbia U.
Category: Experimental R. Hancock
ISSN: 2070-1721 RMR
October 2010
GIST: General Internet Signalling Transport
Abstract
This document specifies protocol stacks for the routing and transport
of per-flow signalling messages along the path taken by that flow
through the network. The design uses existing transport and security
protocols under a common messaging layer, the General Internet
Signalling Transport (GIST), which provides a common service for
diverse signalling applications. GIST does not handle signalling
application state itself, but manages its own internal state and the
configuration of the underlying transport and security protocols to
enable the transfer of messages in both directions along the flow
path. The combination of GIST and the lower layer transport and
security protocols provides a solution for the base protocol
component of the "Next Steps in Signalling" (NSIS) framework.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This document is a product of the Internet Engineering
Task Force (IETF). It represents the consensus of the IETF
community. It has received public review and has been approved for
publication by the Internet Engineering Steering Group (IESG). Not
all documents approved by the IESG are a candidate for any level of
Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5971.
Schulzrinne & Hancock Experimental [Page 1]
RFC 5971 GIST October 2010
Copyright Notice
Copyright (c) 2010 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 . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Requirements Notation and Terminology . . . . . . . . . . . . 5
3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Overall Design Approach . . . . . . . . . . . . . . . . . 8
3.2. Modes and Messaging Associations . . . . . . . . . . . . 10
3.3. Message Routing Methods . . . . . . . . . . . . . . . . . 11
3.4. GIST Messages . . . . . . . . . . . . . . . . . . . . . . 13
3.5. GIST Peering Relationships . . . . . . . . . . . . . . . 14
3.6. Effect on Internet Transparency . . . . . . . . . . . . . 14
3.7. Signalling Sessions . . . . . . . . . . . . . . . . . . . 15
3.8. Signalling Applications and NSLPIDs . . . . . . . . . . . 16
3.9. GIST Security Services . . . . . . . . . . . . . . . . . 17
3.10. Example of Operation . . . . . . . . . . . . . . . . . . 18
4. GIST Processing Overview . . . . . . . . . . . . . . . . . . 20
4.1. GIST Service Interface . . . . . . . . . . . . . . . . . 21
4.2. GIST State . . . . . . . . . . . . . . . . . . . . . . . 23
4.3. Basic GIST Message Processing . . . . . . . . . . . . . . 25
4.4. Routing State and Messaging Association Maintenance . . . 33
5. Message Formats and Transport . . . . . . . . . . . . . . . . 45
5.1. GIST Messages . . . . . . . . . . . . . . . . . . . . . . 45
5.2. Information Elements . . . . . . . . . . . . . . . . . . 48
5.3. D-mode Transport . . . . . . . . . . . . . . . . . . . . 53
5.4. C-mode Transport . . . . . . . . . . . . . . . . . . . . 58
5.5. Message Type/Encapsulation Relationships . . . . . . . . 59
5.6. Error Message Processing . . . . . . . . . . . . . . . . 60
5.7. Messaging Association Setup . . . . . . . . . . . . . . . 61
5.8. Specific Message Routing Methods . . . . . . . . . . . . 66
datatracker.ietf.org