Cisco Cisco IP Contact Center Release 4.6.1 Prospecto
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Cisco Unified Contact Center Enterprise 7.5 SRND
Chapter 3 Design Considerations for High Availability
Understanding Failure Recovery
At this point, the Call Router and Unified CM Peripheral Gateway will run in simplex mode, and the
system will accept new calls from only the surviving side for Unified CCE call treatment. The
Unified IP IVR/Unified CVP functionality will also be limited to the surviving side as well.
system will accept new calls from only the surviving side for Unified CCE call treatment. The
Unified IP IVR/Unified CVP functionality will also be limited to the surviving side as well.
Scenario 4: Unified CCE Agent Site WAN (Visible Network) Failure
The Unified CCE design model for clustering over the WAN assumes the Unified CCE agents are
remotely located at multiple sites connected by the visible WAN. Each agent location requires WAN
connectivity to both of the data center locations across the visible WAN where the Unified CM and
Unified ICM components are located. These connections should provide for redundancy as well as
making use of basic SRST functionality in the event of a complete network failure, so that the remote
site would still have basic dial tone service to make emergency (911) calls.
remotely located at multiple sites connected by the visible WAN. Each agent location requires WAN
connectivity to both of the data center locations across the visible WAN where the Unified CM and
Unified ICM components are located. These connections should provide for redundancy as well as
making use of basic SRST functionality in the event of a complete network failure, so that the remote
site would still have basic dial tone service to make emergency (911) calls.
If side A of the WAN at the Unified CCE Agent Site fails, the following conditions apply:
•
Any IP phones that are homed to the side-A Unified CM subscribers will automatically re-home to
the side-B subscribers (provide the redundancy group is configured).
the side-B subscribers (provide the redundancy group is configured).
•
Agent desktops that are connected to the CTI OS or Cisco Agent Desktop server at that site will
automatically realign to the redundant CTI OS server at the remote site. (Agent desktops will be
disabled during the realignment process.)
automatically realign to the redundant CTI OS server at the remote site. (Agent desktops will be
disabled during the realignment process.)
If both sides of the WAN at the Unified CCE Agent Site fail, the following conditions apply:
•
The local voice gateway will detect the failure of the communications path to the Unified CM
cluster and will go into SRST mode to provide local dial-tone functionality. With Unified CVP, these
gateways detect the loss of the CVP Call Server and execute their local survivability TCL script to
reroute the inbound calls. Active calls in Unified CVP locally would no longer be visible to
Unified CCE, so a Termination Call Detail (TCD) record would be written to the ICM database at
the time of the failure and tracking of the call would stop at that point. The call would execute the
local survivability TCL script, which could redirect it using the PSTN to another Unified CCE site
that remains active; however, the call would then appear as a "new call" to Unified CCE and would
have no relationship with the original call information. If the call is retained locally and redirected
via SRST to a local phone, Unified CCE would not have visibility to the call from that point
forward.
cluster and will go into SRST mode to provide local dial-tone functionality. With Unified CVP, these
gateways detect the loss of the CVP Call Server and execute their local survivability TCL script to
reroute the inbound calls. Active calls in Unified CVP locally would no longer be visible to
Unified CCE, so a Termination Call Detail (TCD) record would be written to the ICM database at
the time of the failure and tracking of the call would stop at that point. The call would execute the
local survivability TCL script, which could redirect it using the PSTN to another Unified CCE site
that remains active; however, the call would then appear as a "new call" to Unified CCE and would
have no relationship with the original call information. If the call is retained locally and redirected
via SRST to a local phone, Unified CCE would not have visibility to the call from that point
forward.
•
The agent desktop will detect the loss of connectivity to the CTI OS Server (or Cisco Agent Desktop
Server) and automatically log the agent out of the system. While the IP phones are in SRST mode,
they will not be able to function as Unified CCE agents.
Server) and automatically log the agent out of the system. While the IP phones are in SRST mode,
they will not be able to function as Unified CCE agents.
Understanding Failure Recovery
This section analyzes the failover recovery of each individual part (products and subcomponents inside
each product) of the Unified CCE solution.
each product) of the Unified CCE solution.
Unified CM Service
In larger deployments, it is possible that the Unified CM to which the agent phones are registered will
not be running the CTI Manager service that communicates with the Unified CM Peripheral Gateway
for Unified CCE. When an active Unified CM (call processing) service fails, all the devices registered
to it are reported “out of service” by the CTI Manager service locally and to any external client, such as
the Peripheral Gateway on a different subscriber CTI Manager service.
not be running the CTI Manager service that communicates with the Unified CM Peripheral Gateway
for Unified CCE. When an active Unified CM (call processing) service fails, all the devices registered
to it are reported “out of service” by the CTI Manager service locally and to any external client, such as
the Peripheral Gateway on a different subscriber CTI Manager service.