After the installation of the Cisco VoIP solution we ran in to several problems in voice quality and echo suppression. First we thought that the problem was related to a hardware problem and paid our attention to the router in this solution. After a while we came to the conclusion that the problem was not related to the router configuration or the router hardware. As we studied the problem more closely we discovered that the Callmanager's memory was nearly full. The problems we ran into where due to a memory leak in the application. We were able to fix the major problems with the service pack for Windows 2000 and the virtual memory fix form Cisco. We also updated the Callmanager Software.
The Cisco VoIP solution can be divided in two parts, a router and a server. For the router we used a Cisco 2600, with the proper additional hardware and for the server we used a Cisco Media Convergence Server 7800. This is a server build with Compaq technology and hardware, which you can see after the complete installation, because it runs also the well known Compaq System management software modules. Besides that it is a Compaq server with a Cisco front it also runs a stripped version of Windows 2000 server. So you can have the benefits of installing the server into the active directory structure or in a standalone environment. Because our server-environment is mostly based on Linux it was no problem to install the server in a standalone version.
The beginning of troubles:
After the installation of the VoIP we noticed several problems:
- We had a lot of echo within a call
- Calls where shutdown in the middle of a conversation after a minute
- The quality of the conversation had not the quality we liked it to have
One of the first causes we found together with the reseller (www.acal.nl) was a defect VIC card. So, we replaced the VIC, but the problems with the echo and the quality remained. The next step was further investigation. First we sorted out if there any known problems at the Cisco Website. We found out that there was already a special Servicepack and a virtual memory fix and a new Callmanager release. With the gathered information in mind we decided to get our things together a get a better look at our VoIP solution.
What we found at the site:
During interviews with the users we found out that the we could relate the problems back to the Cisco Callmanager. One of the first things we did was trying to reboot the Callmanager, but the memory was so full at that moment that the server didn't even want to shut down. So we pressed the button !! After the forced reboot some of the users came to us to inform us that the echo on the conversation had disappeared and that the quality of the conversation was good. So that made us to decide to upgrade the Callmanager from release 3.0x to 3.06, which Cisco referred to us. By following the installation guidelines which we found on the Cisco website the upgrade was a very straight forward operation. After rebooting the system, we cleared the application- and systemlog of the eventviewer to make sure which events came up during the night. We checked the following day if there where any problems with the Callmanager, and there were no problems of any kind.
The problems and complains we had where not related to the Router (after replacing the VIC Card) but related to the Cisco Callmanager version. By updating the software to version 3.06 the quality of the conversation improved and the system became more stable.
In the past week Cisco released version 3.07 and took 3.06 from their download section. We suspect that there where to many bugs in the 3.06 version of the Callmanager.