Campus Clustering
As we have discussed previously, it is assumed there is fast, LAN connectivity
available between servers within a campus.This is essential because with Cisco
CallManager 3.x, clustering across a WAN is not supported. For most campusbased
networks, a single cluster solution is adequate. Call admission control is not
required within a campus, but the following restrictions do apply:
Maximum of 10,000 total registered devices
Maximum of eight servers per cluster
Maximum of 2,500 registered IP phones, or 3,000 other devices per
CallManager
Switched infrastructure to the desktop
You should ensure that the maximum redundancy and load-balancing options
are provided by your cluster. It is important to consider that typically, some sites
within a campus will have only a single high-speed IP link to the rest of the
MAN. In such cases, it is essential that CallManagers are placed on site, to ensure
system availability in the event of a link failure. Figure 4.5 illustrates a typical
MAN, and how clustering might be used to ensure a high-availability and highperformance
system.