Many strategies can identify the location of a IP Telephony problem. For example, one could pinpoint the location of a problem by using the procedure below.
Procedure
Analyze protocol layers from the bottom up, starting at the physical layer.
First analyze the perceived voice impairments (echo, delay, and voice clipping) if any, and then analyze signaling and network impairment problems.
Start with a solution that is most likely to resolve the problem, followed by less likely solutions if necessary.
Look at large behavioral patterns:
Do other IP Telephones on the same subnetwork/VLAN, floor, switch port, router media module, procr, network region, campus, software or firmware version, or Communication Managerversion have the same problem? Similar problems with multiple IP Telephones might indicate shared resource problems such as power problems, Ethernet switch or IP router problems, or remote connectivity WAN problems. It may also indicate software or firmware version problems.
Does the problem repeat at a specific time of day? At specific times, the network load may be higher, which might cause your system to run out of IP Telephony resources.
Look for simple solutions, for example, if only one IP telephone has a problem:
If exchanging the IP telephone solves the problem, then the IP telephone is likely the source of the problem, unless the problem is intermittent.
If the problem is solved when the IP telephone is connected to a different Ethernet switch port or IP router port, then the IP telephone is not the problem.
Are compatible codecs used? Review the network region administration for end-to-end compatibility.
