Inter-Cluster Cisco Ip Phone-To-Cisco Ip Phone Calls; Sample Topology; Inter-Cluster H.323 Communication - Cisco 30 VIP Troubleshooting Manual

For cisco callmanager release 3.0(1)

Hide thumbs Also See for 30 VIP:

Table of Contents

Cisco IP Telephony Troubleshooting Guide for Cisco CallManager Release 3.0(1)

Appendix C – Troubleshooting Case Study 3

Inter-Cluster Cisco IP Phone-to-Cisco IP Phone Calls

In the previous case studies, the call flow and troubleshooting techniques of an intra-cluster call

and a Cisco IP Phone call through a Cisco IOS Gateway to a phone hanging off of a local PBX

or somewhere on the PSTN have been discussed in detail. This case study examines a

Cisco IP Phone calling another Cisco IP Phone located in a different cluster. This type of call is

also known as an inter-cluster Cisco IP Phone call.

The following is the sample topology is used in this case study. There are two clusters, each

having two Cisco CallManagers. There are also Cisco IOS Gateways and a

Cisco IOS Gatekeeper in place.

As you can see in the topology, the Cisco IP Phone in Cluster 1 is making a call to the

Cisco IP Phone in Cluster 2. Inter-cluster Cisco CallManager communication takes place using

the H.323 Version 2 protocol. There is also a Cisco IOS Gatekeeper for admission control. The

detailed explanation of the debug output and show commands, and the interaction between the

Cisco IOS Gatekeeper and Cisco IOS Gateway and Cisco CallManager devices can be reviewed

in the previous sections.

The call flow process is shown in the diagram below. The Cisco IP Phone can talk to the

Cisco CallManager via Skinny Station protocol, and the Cisco CallManager can talk with the

Cisco IOS Gatekeeper using the H.323 RAS protocol. The Admission Request message (ARQ)

is sent to the Cisco IOS Gatekeeper, which sends the Admission Confirmed message (ACF) after

Table of Contents