RFC 3204 (rfc3204) - Page 2 of 10
MIME media types for ISUP and QSIG Objects
Alternative Format: Original Text Document
RFC 3204 ISUP and QSIG MIME Objects December 2001
QSIG is the analogous signaling protocol used between private branch
exchanges to support calls within private telephony networks. There
is a similar need to transport QSIG-encoded signaling information
between SIP entities in some environments.
This document is specific to this usage and would not apply to the
transportation of ISUP or QSIG messages in other applications. These
media types are intended for ISUP or QSIG application information
that is used within the context of a SIP session, and not as general
purpose transport of SCN signaling.
The definition of media types for ISUP and QSIG application
information does not address fully how the non-SIP and SIP entities
exchanging messages determine or negotiate compatibility. It is
assumed that this is addressed by alternative means such as the
configuration of the interworking functions.
This is intended to be an IETF approved MIME type, and to be defined
through an RFC. NOTE: usage of Q.SIG within SIP is neither endorsed
nor recommended as a result of this MIME registration.
3. Proposed new media types
ISUP and QSIG messages are composed of arbitrary binary data that is
transparent to SIP processing. The best way to encode these is to use
binary encoding. This is in conformance with the restrictions imposed
on the use of binary data for MIME (RFC 2045 [3]). It should be noted
that the rules mentioned in the RFC 2045 apply to Internet mail
messages and not to SIP messages. Binary has been preferred over
Base64 encoding because the latter would only result in adding bulk
to the encoded messages and possibly be more costly in terms of
processing power.
3.1 ISUP Media Type
This media type is defined by the following information:
Media type name: application
Media subtype name: ISUP
Required parameters: version
Optional parameters: base
Encoding scheme: binary
Security considerations: See section 5.
The ISUP message is encapsulated beginning with the Message Type Code
(i.e., omitting Routing Label and Circuit ID Code).
Zimmerer, et al. Standards Track