I have a 40Mb MOE connection terminating on FE0/0 in a Cisco 2611xm router at a peripheral site. FE0/1 on the Cisco 2611xm trunks to our switch statck. At the site, workstations on the switch stack can transmit/recieve at 100mb/sec as expected. When a workstation tries to recieve from the MOE, it bottlenecks at around 10-11 Mbs. However, a workstation can send across the MOE to one of our other sites at 40Mbs. I have several sites all configured the same way and none of the other sites are exibiting this problem. My MOE provider is saying everything looks clean on their equipment and the same is true for my equipment. All the counters are clean. The circuit just won't transmit faster than 40Mbs. Here is my question. I have narrowed the problem to either the circuit, the router or the uplink switchport. Without replacing the router or moving the router to switch connection to a different switchport, how can I debug this and make sure I don't have a bad ethernet interface in my 2611 or a bad swithcport? What debugging is possible that might shed some light on this problem?