On Wed, 2009-02-25 at 11:21 +0530, lakshmi wrote: > We are extending our SIP stack to support for MESSAGE method . Handling > MESSAGE outside the dialog is clear. The spec 3428 is not clearly > mentioned how to handle MESSAGE with in the dialog. Not cleared with in > dialog, on which states MESSAGE request/response must allow? Kindly > suggest how to handle MESSAGE with in dialog ?
The bigwigs of SIP do not like the idea of sending a stream of MESSAGE requests because it is a fairly high-overhead method of operating. The preferred technique is to use INVITE to set up an MSRP session. See RFC 4975 for the details. So the documentation of MESSAGE explicitly only supports out-of-dialog use. See RFC 3428 section 2: This document describes the use of the MESSAGE method for sending instant messages using a metaphor similar to that of a two-way pager or SMS enabled handset. That is, there are no explicit association between messages. Each IM stands alone--any sense of a "conversation" only exists in the client user interface, or perhaps in the user's own imagination. We contrast this with a "session" model, where there is an explicit conversation with a clear beginning and end. In the SIP environment, an IM session would be a media session initiated with an INVITE transaction and terminated with a BYE transaction. However, given the structure of SIP, it is clear how one would send multiple MESSAGE requests within a dialog -- the first MESSAGE obtains a to-tag and possibly a route-set, and all following MESSAGEs use the tags and route-set. But it's still better to use MSRP for session-type messaging. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
