Transcript IMS-based

INTRODUCTION
1.1 Why the Internet Protocol Multimedia
Subsystem
1.2 Where did it come from?
1.1 WHY THE INTERNET
PROTOCOL MULTIMEDIA
SUBSYSTEM

New communication paradigm
networking Internet Protocol (IP)-based mobile
devices
 terminals
 large, high-precision displays
 built in cameras and a lot of resources for
applications
 always-on-always-connected application devices


applications
 no longer isolated entities exchanging information
 more exciting applications are peer-to-peer entities,
which facilitate sharing
 browsing
 whiteboard
 game experience
 two-way radio session (i.e., push to talk)
Figure 1.1 shows the key ingredient to a peer-topeer connection between the new IP-enabled
mobile devices
 IMS


a global system used to enable applications in mobile
devices to establish peer-to-peer connections

True integration of voice and data services


increases productivity and overall effectiveness
The development of innovative applications
integrating voice, data and multimedia will
create demands for new services
presence
 multimedia chat
 conferencing
 push to talk


Figure 1.2 shows
a consolidated network where the IMS introduces
multimedia session control in the packet-switched
domain
 at the same time brings circuit-switched functionality
in the packet-switched domain


Traditional mobile communication system has
been divided in three parts
terminals
 radio access network (RAN)
 core network


With IMS-based system
"radio access network" should be replaced by "access
network"
 an IMS system can be deployed over non-RANs as
well

1.2 WHERE DID IT COME FROM?
1.2.4 3GPP Release 5 and Release 6
1.2.4 3GPP RELEASE 5 AND RELEASE
6
Release 5 introduced IMS as part of 3GPP
standards
 IMS is a standardized access-independent IPbased architecture

interworks with existing voice and data networks for
both
 fixed network users (e.g., PSTN, ISDN, Internet)
 mobile users (e.g., GSM, CDMA)
 is able to establish peer-to-peer IP communications
with all types of clients with the requisite quality of
services


functionalities
 session management
 complete service delivery
 e.g., registration, security, charging, bearer
control, roaming
The functional content of 3GPP Release 5 was
frozen in March 2002
 Release 6 is completed in 2004
 Table 1.1 shows the most important features of
Release 5 and the items postponed to Release 6

AKA:Authentication and Key Agreement


3GPP has defined a finite architecture for SIP-based
IP multimedia service
 a functionality of logical elements
 a description of how elements are connected
 selected protocols and procedures
Optimization for the mobile communication
environment has been designed in the form of
 user authentication and authorization based on
mobile identities
 definite rules at the user network interface for
compressing SIP messages
 security and policy control mechanisms that allow
radio loss and recovery detection
IMS development is distributed to multiple
working groups in 3GPP
 The working method has three different stages

stage 1
 a service description from a service user and
operator point of view are evaluated
 stage 2
 problems are broken down into functional elements
and the interactions between the elements are
identified



stage 3
 all the protocols and procedures are defined in
detail
Figure 1.3 shows

the most important working groups and
responsibility areas that are involved in the
development of IMS