Cisco Cisco E-Mail Manager Unity Integration Option Leaflet
11-11
Cisco Unified Contact Center Enterprise 7.5 SRND
Chapter 11 Sizing Cisco Unified Communications Manager Servers
Load Balancing Unified CM
Load Balancing Unified CM
An additional benefit of using the 1:1 redundancy scheme is that it enables you to balance the devices
over the primary and backup subscriber pairs. Normally (as in the 2:1 redundancy scheme) a backup
server has no devices registered unless its primary is unavailable.
over the primary and backup subscriber pairs. Normally (as in the 2:1 redundancy scheme) a backup
server has no devices registered unless its primary is unavailable.
With load balancing, you can move up to half of the device load from the primary to the secondary
subscriber by using the Unified CM redundancy groups and device pool settings. In this way, you can
reduce by 50% the impact of any server becoming unavailable.
subscriber by using the Unified CM redundancy groups and device pool settings. In this way, you can
reduce by 50% the impact of any server becoming unavailable.
To plan for 50/50 load balancing, calculate the capacity of a cluster without load balancing and then
distribute the load across the primary and backup subscribers based on devices and call volume. To allow
for failure of the primary or the backup, the total load on the primary and secondary subscribers should
not exceed that of a single subscriber. For example, if deploying Unified CVP and Unified CM 7.0 or
later, MCS-7845 servers have a total server limit of 1,000 Unified CCE agents. In a 1:1 redundancy pair,
you can split the load between the two subscribers, configuring each subscriber with 500 agents. To
provide for system fault tolerance, make sure that all capacity limits are observed so that Unified CCE
agent phones, Unified IP phones, CTI limits, and so on, for the subscriber pair do not exceed the limits
allowed for a subscriber server.
distribute the load across the primary and backup subscribers based on devices and call volume. To allow
for failure of the primary or the backup, the total load on the primary and secondary subscribers should
not exceed that of a single subscriber. For example, if deploying Unified CVP and Unified CM 7.0 or
later, MCS-7845 servers have a total server limit of 1,000 Unified CCE agents. In a 1:1 redundancy pair,
you can split the load between the two subscribers, configuring each subscriber with 500 agents. To
provide for system fault tolerance, make sure that all capacity limits are observed so that Unified CCE
agent phones, Unified IP phones, CTI limits, and so on, for the subscriber pair do not exceed the limits
allowed for a subscriber server.
Cisco recommends the equal distribution of all devices and call volumes as much as possible across all
active subscribers. For instance, distributing the Unified CCE agents, CTI ports, gateways, trunks,
voicemail ports, and other users and devices among all subscribers equally, minimizes the impact of any
outage.
active subscribers. For instance, distributing the Unified CCE agents, CTI ports, gateways, trunks,
voicemail ports, and other users and devices among all subscribers equally, minimizes the impact of any
outage.
For additional information on general call processing topics such as secondary TFTP servers and
gatekeeper considerations, refer to the Cisco Unified Communications Solution Reference Network
Design (SRND) guide, available at
gatekeeper considerations, refer to the Cisco Unified Communications Solution Reference Network
Design (SRND) guide, available at
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guides
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Deployment of Agent PG in a Unified CM Cluster
Agent PGs can be deployed in a Unified CM cluster in either of the following ways:
•
The first method is to deploy an Agent PG for each pair of Cisco Unified CM subscriber nodes. In
this case, each Unified CM subscriber node runs the CTI Manager service, and each Agent PG
connects to a CTI Manager running on its corresponding Unified CM subscriber pair. The following
diagram shows an example where four primary Unified CM subscribers are required and four
backup Unified CM subscribers are deployed to provide 1:1 redundancy.
this case, each Unified CM subscriber node runs the CTI Manager service, and each Agent PG
connects to a CTI Manager running on its corresponding Unified CM subscriber pair. The following
diagram shows an example where four primary Unified CM subscribers are required and four
backup Unified CM subscribers are deployed to provide 1:1 redundancy.
•
Another possible method is to deploy a single Agent PG for the entire Cisco Unified CM cluster.
This type of deployment requires a single pair of Cisco Unified CM subscriber nodes running CTI
Manager. Agent phone registration should be spread among all the Cisco Unified CM subscriber
This type of deployment requires a single pair of Cisco Unified CM subscriber nodes running CTI
Manager. Agent phone registration should be spread among all the Cisco Unified CM subscriber
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