Cisco ASR 5000 series Product Overview page 594

▀ Features and Functionality - Base Software
Short Code Dialing
TAS Basic provides basic voice call feature support in the SCM. In the IMS architecture, these telephony features are
normally provided by an external application server. Providing these features with the S-CSCF:
Reduces the need for an additional SIP AS
Simplifies the network architecture
Improves latency for call setup and feature invocation
The following describe the local basic call features implemented on the S-CSCF:
Abbreviated Dialing (AD) - This feature allows the subscriber to call a Directory Number by entering less than
the usual ten digits.Usually, the subscriber has four digit dialing to mimic PBX dialing privileges but these
must be set up prior to use. When the SCM receives these numbers, it translates them and routes the call.
Call Forward Busy Line (CFBL) - This feature forwards the call if busy line indication is received from the
UE. If CFBL is enabled on both the AS and the S-CSCF, the call is forwarded by the S-CSCF on Busy Line
indication. The feature detects and eliminates call forward loops if the History-Info header is present. It also
terminates forwarding if forwarding causes the forward attempts to be more than the number specified in the
Max-Forwards header.
Call Forward No Answer (CFNA) - This feature forwards the call if no answer is received from the UE. If
CFNA is enabled on both the AS and the S-CSCF, the call is forwarded by the S-CSCF on No Answer
indication. The feature detects and eliminates call forward loops if the History-Info header is present. It also
terminates forwarding if forwarding causes the forward attempts to be more than the number specified in the
Max-Forwards header.
Call Forward Not Registered (CFNR) - This feature forwards the call if the subscriber is not registered. If
CFNR is enabled on both the AS and the S-CSCF, the call is forwarded by the S-CSCF on Not Registered
indication. The feature detects and eliminates call forward loops if the History-Info header is present. It also
terminates forwarding if forwarding causes the forward attempts to be more than the number specified in the
Max-Forwards header.
Call Forward Unconditional (CFU) - This feature unconditionally forwards the call. The check for local CFU
is done prior to the filter criteria and before any AS interaction. Thus CFU is enabled on both the S-CSCF and
the destination AS, the local CFU occurs and there is no AS interaction. The feature eliminates basic loop
detection (A calls B which is forwarded to A) and if the History-Info header is present, enhanced loop
detection is performed based on the contents of this header. It also terminates forwarding if forwarding causes
the forward attempts to be more than the number specified in the Max-Forwards header.
Call Transfer - This feature allows the subscriber to transfer a call.
Call Waiting - This feature allows the subscriber to receive a second call while on the first call.
Caller ID Display (CID) - This feature inserts P-Preferred-Identity which communicates the identity of the user
within the trust domain. If this header is already present, the feature may not do anything different.
Caller ID Display Blocked (CIDB) - This feature removes P-Preferred-Identity and P-Preferred-Asserted-
Identity headers and inserts a Privacy header with the privacy value set to ―id‖.
Feature Code Activation/De-activation - This feature allows for activating and de-activating certain features
using a star (*) - number sequence (star code). Registered subscribers have the option of activating or
deactivated call features using specified star codes. The SCM translates these codes and routes the call.
Follow Me/Find Me - This feature invokes the incoming call to several configured destinations in parallel and
connects the call to the first destination that responds, ―tearing down‖ all the other calls. There are two possible
implementations of this feature; one a sequential implementation in which each destination is attempted in
▄ Cisco ASR 5000 Series Product Overview
Session Control Manager Overview
OL-22938-02