Subject: [dispatch] Session-Id: Problem 1: What is a "session"?

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Wed, 9 Nov 2011 13:20:39 -0500

As Keith notes, the word "session" is overloaded.

The *original* meaning is clear, it is a set of media streams
described by SDP, the *Session Description Protocol*.  SIP, the
Session Initiation Protocol, is a "wrapper" that allows two devices to
negotiate a session between themselves.  That is why SIP INVITE
requests carry SDP payloads.

(In the hierarchy of grouping, "dialog" sits here.)

The *other* meaning of "session" is not rigidly defined, but
corresponds more to what people think of as phone calls.  In
particular, in the common situation of a B2BUA whose intent is to pass
a call onward, the "incoming" and "outgoing" SIP dialogs are
considered part of the same "session".

Should we call them "little sessions" (= SDP sessions) and "big
sessions"?  ;-)

Dale

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From: "Olle E. Johansson" <[email-masked]>
Date: Wed, 9 Nov 2011 21:56:06 +0100

> Should we call them "little sessions" (= SDP sessions) and "big

Media sessions - msessions - or just sessions

Dialog sessions - dsessions

But that gets to confusing

Dialog groups is propably a better term to use. I could explain a dialog group as a group of dialogs.

--------

Dialog-group: Identifier for a group of Dialogs

Dialogs: identied by a call-iD and more

Session: A media session, described by SDP

/O