Subject: [Simple] question regarding IP and port negotiation with sdp

From: prasun bheri <[email-masked]>
Date: Wed, 5 Oct 2011 12:10:12 +0530

Hello group,

I have a question regarding IP and port negotiation with sdp

Lets say A and B are two MSRP nodes (End points) with a file transfer going
on between them.

If A wants to initiate one more file transfer to B…

Which port should A has to use in the following scenarios?

Case 1:

A keeps the same port that its using for First file transfer in the SDP, and
B returns the same IP and port number in response to SDP.

Hence both will use the same connection for second file transfer too.

Case 2:

A keeps the same port that its using for First file transfer in the SDP, and
B returns a different IP and/port number in response to SDP.

then

i.                     A has to use the same port and a different connection
(create a TCP socket, bind to the same port and then connect)

 What are the implications in this case ?

ii.                   A has to different port and a different connection

Then the port in a=path attribute has no meaning?

Will remote end accepts the connection as ports are different in initial SDP
and actual connection request.