Session Control Manager Overview
Cisco ASR 5000 Series Product Overview ▄
Figure 145. Access Border Gateway
A-BG
SLF
Application
Servers
Home
Subscriber
Server
Access Network
IMS Core
Proxy-CSCF
The primary point of entry into the IMS network is the Proxy-CSCF (P-CSCF). The P-CSCF is responsible for:
providing message manipulation to allow for localized services (traffic/weather reports, news, directory services,
etc.)
initiating the breakout of emergency service calls
Topology Hiding Inter-network Gateway (THIG)
Quality of Service (QoS) authorization
number conversions for local dialing plans
terminate IPSec tunnels
The P-CSCF is the handset‘s first point of entry into the IMS and is also the outbound proxy for SIP. Once the P-CSCF
has completed all of the functions for which it is responsible, the call setup is handed off to the Interrogating-CSCF (I-
CSCF).