SIP peers connectivity problem

Hi,

After using asterisk for about a year without any problems, lately I’m having audio problems: conversations are breaking (not dropped though), voice skips for seconds, can only hear every other syllable.

For a quick fix I always restarted asterisk and the Linux server and the problem was gone for a day. I left the console running now and noticed several lagged, reachable, unreachable messages. The peers are also showing 2-3000msec! delays randomly. Since this is on a LAN, these are certainly problematic values. After a reboot the pings are in the 5-15msec range.

What could be the cause of this? A faulty switch?

I’m running asterisk 1.6.2.13 in a VMware Vsphere 4.1 environment, with 18 users.

Trying to run under VMWare.