March 2006
Intermediate to advanced
464 pages
12h 16m
English
book
The IMS: IP Multimedia Concepts And Services, Second Edition
by Miikka Poikselka, Georg Mayer, Hisham Khartabil, Aki Niemi
Content preview from The IMS: IP Multimedia Concepts And Services, Second Edition
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
11.4. Compression negotiation
11.4.1. Overview
The basic compression capabilities of the UE and the P-CSCF have already been negotiated during the registration procedures (see Section 10.9). Consequently, all requests and responses that are sent between the two sets of UE and their P-CSCFs will be compressed.
In this example we only show how compression parameters are basically set during session establishment and concentrate only on the compression between Theresa's UE and her P-CSCF. The procedures for Tobias's end are identical.
11.4.2. Compression of the initial request
We assume that Theresa has registered a contact address that included the comp=SigComp parameter at her S-CSCF. Therefore, Theresa's S-CSCF will include this parameter when it acts as a SIP registrar and re-writes the request URI of the INVITE request (see Section 11.3.3.5).
INVITE sip:[5555::5:6:7:8]:1006;comp=SigComp SIP/2.0
When the P-CSCF receives this request, it will route it toward Theresa's UE based on the request URI and, as the comp=SigComp parameter is included, it will send it compressed. Furthermore, the P-CSCF will:
add the comp=SigComp parameter to its entry in the Via header, so that Theresa will send all responses to the INVITE request compressed;
add the comp=SigComp parameter to its entry in the Record-Route header, so that Theresa will send all subsequent requests in this dialog compressed.
Our INVITE request now looks like:
INVITE sip:[5555::5:6:7:8]:1006;comp=SigComp SIP/2.0 Via: SIP/2.0/UDP ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.