Cisco Cisco IPCC Web Option Design Guide
11-10
Cisco Unified Contact Center Enterprise 7.0, 7.1, and 7.2 SRND
OL-8669-16
Chapter 11 Sizing Cisco Unified Communications Manager Servers
Load Balancing Unified CM
Figure 11-2
1:1 Redundancy Configuration Options
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, MCS-7845 servers have a total server limit of 500
Unified CCE agents. In a 1:1 redundancy pair, you can split the load between the two subscribers,
configuring each subscriber with 250 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, MCS-7845 servers have a total server limit of 500
Unified CCE agents. In a 1:1 redundancy pair, you can split the load between the two subscribers,
configuring each subscriber with 250 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.
M
M
126040
MAX 150 AGENTS
MAX 500 AGENTS
MAX 1000 AGENTS
Publisher and
Backup Subscriber
Primary
Backup
Publisher and TFTP Server(s)
Primary
1
M
M
2
Backup
Publisher and TFTP Server(s)
Primary
M
M
3
MAX 1500 AGENTS
Backup
Primary
M
M
Publisher and TFTP Server(s)
Publisher and TFTP Server(s)
4
5
MAX 2000 AGENTS
Backup
Primary
M
M
Backup
Primary
M
M
Backup
Primary
M
M
Backup
Primary
M
M
Backup
Primary
M
M
Backup
Primary
M
M
Backup
Primary
M
M