Cisco ASR 5000 Series - Interrogating-CSCF

Session Control Manager Overview
▀ Product Description
▄ Cisco ASR 5000 Series Product Overview
OL-22938-02
Interrogating-CSCF
The I-CSCF performs mostly as a load distribution device. The I-CSCF queries the Home Subscriber Server (HSS) to
identify the appropriate Serving-CSCF (S-CSCF) to which the call is sent. Since the HSS maintains user profile
information (much like the Home Location Register (HLR) in the Public Land Mobile Network (PLMN)), the I-CSCF
can identify the proper S-CSCF for the call. The I-CSCF may also query a AAA server to determine subscriber profile
information using DIAMETER.
Important: The I-CSCF is incorporated into the S-CSCF.
I-CSCF Interfaces
The following diagram shows the interfaces/reference points associated with the I-CSCF:
ENUM
Server
S-CSCF
P-CSCF
HSS
I-CSCF
Transit
Functions
CDF
Cx
Mw
ENUM
Rf
SIP
Serving-CSCF
The Serving-CSCF (S-CSCF) is the access point to services provided to the subscriber. Service examples include
session control services, such as call features.
Other services include:
VPN
Centralized speed dialing lists
Charging
The S-CSCF also interacts with the HSS for:
User authentication
Emergency registration
Location management
User data handling
A Breakout Gateway Control Function is integrated into the SCM‘s S-CSCF to support PSTN calls.