Help choppy calls

I currently have cisco 2950 switches ans using asterisk with polycom and aastra sip phones i have tried just a few things on our switches how ever i think i am failing at everything. We are getting very choppy calls during busy periods of the day. I know the 2950 do not support full qos what options do i have ?

thanks!!

You didn’t specify whether the choppy calls are within your network. Meaning are you making a call from one extension to another or terminating using a TDM or Voip provider?

If so what kind of bandwidth do you have allocated for such calls?

Sorry i did not specify we have a PRI not a voip provider, the choppy calls are internal and external both.

I had this issue when i installed asterisk on a Virtual Machine i sorted it by installing it on a full system.