Appendix B Case Study: Troubleshooting Cisco Unified IP Phone Calls

Troubleshooting Intercluster Cisco Unified IP Phone Calls

16:05:45.312 CCMStationD - stationOutputStartMediaTransmission tcpHandle=0x4fbb150 myIP: e64610ac (172.16.70.230)

16:05:45.328 CCMStationD - RemoteIpAddr: e74610ac (172.16.70.231) RemoteRtpPortNumber:

18448 msecPacketSize: 20 compressionType:(4)Media_Payload_G711Ulaw64k 16:05:46.203 CCMStationInit - InboundStim - OnHookMessageID tcpHandle=0x4fbbc30

The calling party Cisco IP Phone finally goes on hook, which terminates all the control messages between the Skinny Station and Cisco Unified CallManager as well as the RTP stream between Skinny Stations.

16:05:46.203 CCMStationInit - InboundStim - OnHookMessageID tcpHandle=0x4fbbc30

Troubleshooting Intercluster Cisco Unified IP Phone Calls

The case study in this section examines a Cisco Unified IP Phone that is calling another

Cisco Unified IP Phone that is located in a different cluster. This type of call is also known as an intercluster Cisco Unified IP Phone call.

This section contains the following topics:

Sample Topology

Intercluster H.323 Communication

Call Flow Traces

Failed Call Flow

Sample Topology

The following sample topology gets used in this case study. Two clusters, each having two

Cisco Unified CallManagers, and also Cisco IOS Gateways and a Cisco IOS Gatekeeper are in place.

Intercluster H.323 Communication

The Cisco IP Phone in Cluster 1 makes a call to the Cisco Unified IP Phone in Cluster 2. Intercluster Cisco Unified CallManager communication takes place using the H.323 Version 2 protocol. A Cisco IOS Gatekeeper also serves for admission control.

The Cisco Unified IP Phone can connect to the Cisco Unified CallManager via Skinny Station protocol, and the Cisco Unified CallManager can connect with the Cisco IOS Gatekeeper by using the H.323 Registration, Admission, and Status (RAS) protocol. The admission request message (ARQ) gets sent to the Cisco IOS Gatekeeper, which sends the admission confirmed message (ACF) after making sure the intercluster call can be made using H.323 version 2 protocol. Once this happens, the audio path gets made by using the RTP protocol between Cisco Unified IP Phones in different clusters.

Call Flow Traces

This section discusses the call flow by using SDI trace examples captured in the CCM000000000 file. The traces discussed in this case study focus only on the call flow itself.

Troubleshooting Guide for Cisco Unified CallManager Release 5.0(2)

 

OL-9420-01

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Cisco Systems OL-9420-01 appendix Intercluster H.323 Communication, Call Flow Traces