| Description | The SIP service table lists each Customer Voice Portal SIP
service configured on this server. The CVP SIP service is a
software module which always resides in the CVP Call Server.
The CVP SIP service is a SIP Back-to-Back User Agent (B2BUA).
On the front end, it supports two SIP call legs, one incoming
and one outgoing. This service does not terminate RTP flows;
it only deals with SIP messages. On the back end, the SIP
service implements the (GED-125) Service Control Interface
(SCI) to the Cisco Intelligent Contact Management (ICM)
application for call control functions only (no VRU scripts).
The purpose of a B2BUA is to act as an active intermediary
for a call, communicating with both the source and the
destination legs of the call, and providing 3rd party call
control capabilities on behalf of a routing engine (such as
the ICM contact router). Because it must track the call
throughout its life, it becomes a key source of call-level
reporting data and a natural place for moderating call
switching resources.
Generally speaking, a SIP B2BUA is two User Agents (UAs).
The device receives incoming calls in one UA and immediately
creates an outgoing call via its other UA. Thereafter, all
SIP messages from either one are forwarded to the other.
What makes it useful is the fact that it puts ICM in between
the two legs. On incoming calls, it asks the ICM where the
outgoing call should be addressed. Once the call has been
delivered, ICM has the opportunity to end the outgoing leg
and reconnect it to a subsequent destination. In practice,
there will typically be a delivery to the subsequent agents
(call center agents - a human resources tasked with answering
inbound calls and providing specific services) or back to
the VRU leg.
The SIP service table has a sparse dependent relationship
with the (generic) ccvpService table. The service index acts
as the primary index, relating the entry to the corresponding
entry in the ccvpService table.
The SNMP agent constructs this table at startup. Since
services can only be added or deleted when the CVP
application is stopped, service information entries cannot be
added to or deleted from the table either by the agent or the
management station while the application is running. The
agent will update service information table objects as their
values change when the application is running. All objects
in this table are read-only to the management station. |