When should a VoIP system be analyzed and with what tools?

We have recently implemented a VoIP network with separate VLANs and QoS. It all seemed to be working fine when it first went in, but recently, certain people have been complaining about sound breakup whilst talking to customers on the phone. I have also had similar problems, but thought it was due to the amount of diagnostics software that I was running on my PC.

To check, I moved my phone into its own port and the breakup is still there. Any ideas how we can check to make sure that the network is doing alright? Also are there any software utilities that would help us with day to day analyzing?

First and foremost -- I would suggest that you have someone come and test your cabling channels. That will be the least expensive and could be the most worrisome component. Even if the channels tested fine when first installed, they can degrade over time with moves, adds and changes.

The other thing you didn't mention was if this occurs only on the intra-office calls or only on outside calls. If it is only on outside calls, you may want to get your carrier to check your circuits.

If these things test out okay, then you will want a RMON tool that can track performance. Check your switch SNMP data for errors. These will also give you a good idea of what the culprit may be. If this is happening to everyone in the building -- start looking for common denominators such as network interface cards in the switch.