AT&T, provisioning and what they don’t tell you

So we were recently trying to get our COS or quality of service working on our MPLS network which is provided by AT&T. After dealing with countless people in Tier 1 and 2 I finally spoke with someone in Tier 3 who actually new something. A little background on COS first. You divide all your traffic up into 4 COS levels with COS1 being real time traffic. So you can give 60 percent of your bandwidth to COS2, 20 percent to COS3 and 20 percent to COS4 giving you 60/20/20 and then you decide real time traffic such as 20 percent which sits on top of that. We had numerous problems getting our Avaya phone system to work but as it turns out, AT&T has since fixed this by looking at the packet headers that are assigned by your own equipment. But I digress, so as it turns out by putting terminal server traffic into COS1 with our phone traffic, anything beyond 20 percent is dropped. This caused major headaches as to why terminal services, was so slow for our end users. By moving terminal services traffic on port 3389 to COS2 we were able to eliminate our packets being dropped and everything works great now!