A, B, C and D

All four of these are valid Cisco CallManager designs. E is incorrect because you need at least one call-processing agent in each cluster.

A

A 1:1 redundancy design offers maximum redundancy because each Cisco CallManager involved in call processing has a dedicated backup server. This model is often very cost prohibitive to most companies.

C and D

Although using a single cluster over WAN connections has very strict delay and bandwidth requirements, there are plenty of benefits. A common dial plan across all sites allows the network administrator to create a single dial plan, which replicates to all remote sites. In addition, if a Cisco CallManager fails, the IP Phones can failover to a Cisco CallManager server at another site, maintaining their full feature set.

B and C

Every Cisco CallManager cluster should have at least two servers, which allows call processing to continue should a single server fail. The data of the voice network is made redundant through the SQL database replication that occurs between servers in the cluster.

B

There can only be a single publisher server for the entire Cisco CallManager cluster. This is a SQL 2000 database restriction as the SQL publisher maintains the only writable copy of the database.

C

A Cisco CallManager cluster supports a single SQL publisher and up to eight SQL subscriber servers.

B

Survivable Remote Site Telephony (SRST) is absolutely necessary in a centralized Cisco CallManager design. SRST supports the remote IP Phones, providing PSTN calling access if the WAN connection fails.

True

If the Cisco CallManager server at a location fails, the IP Phones can failover to another Cisco CallManager server at a remote site.

A and C

The H.323 gatekeeper and SIP proxy server have the ability to be the centralized point of dial plan information. This keeps the network administrator from having to re-create the network dial plan at each of the sites.

E

Cisco will support a maximum cluster size of 30,000 IP Phones in Cisco CallManager 4.0. This large cluster size was introduced in Cisco CallManager version 3.3 and was a tremendous increase from earlier Cisco CallManager versions.