About The Crs Active Server - Cisco CRS-1 - Carrier Routing System Router Administration Manual

Chapter 1 Introducing Cisco Customer Response Solutions
About CRS Cluster Architecture
CRS cluster can support up to two CRS Servers, one designated as the active CRS
Server and the other designated as the standby CRS Server for high availability
purposes.
The LDAP server stores information about the cluster in a cluster profile. A
cluster profile is an LDAP Organizational Unit that contains a set of LDAP
entries, which include data relating to the Cisco CRS servers, components, and
licenses installed in a cluster. A cluster profile allows the use of the same LDAP
entries for multiple servers.
When you install or upgrade Cisco CRS on a server, you designate the cluster to
which the server will belong by designating the cluster profile for that cluster.
Cluster architecture accommodates high availability and failover since, in case of
the failure of a component, a secondary server will take over the functionality lost
by that failed component.
All CRS servers within the cluster are configured identically and installed with
the same features. One server is designated the active server.

About the CRS Active Server

The CRS active server makes global decisions for the cluster and keeps track of
calls in the CSQs, agent states (if Unified CCX is installed) and generating
historical detail records.
Note Only one server in the cluster can be the active server at any given time.
If the active server fails, the Cisco CRS platform provides automatic failover to
the standby server. If the active server fails (for example, in the event a hardware
failure occurs or the CRS Engine process terminates), some calls being handled
by the server are lost. The lost calls are restricted to those being handled by the
system (those in the IVR stage or in queue). Calls answered by agents continue to
remain live even though related data on the agent desktop is lost. When the
standby server takesover as the new active server, call processing continues (see
High Availability and Automatic Failover, page 8-6).
A Cisco CRS cluster consists of the one or more servers (nodes) that run Cisco
CRS components in your Cisco CRS deployment (see Control Center
Terminology, page 8-2).
Cisco Customer Response Solutions Administration Guide, Release 4.1(1)
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