I had an issue where EIGRP was choosing to route all traffic over a T1 instead of a 10 Mbit circuit. When I changed the router's ethernet interface connected to the 10 Mbit circuit from Half Duplex to Full Duplex the routes changed to use the 10 Mbit circuit. I looked through the EIGRP metrics and I don't see where that would factor into the calculation of choosing a route. The T1 route and 10 Mbit route are both going to the same router, same number of hops, same delay, only the T1 is much slower than the 10 Mbit circuit and yet EIGRP on the router chose the T1. Would the interface being set to Half Duplex cause EIGRP to choose a T1 over a 10 Mbit circuit? I tested this on equipment at home and EIGRP always chooses the route with the fastest configured bandwidth even if the interface is set to Half Duplex. Would Half Duplex cause this in some situations? Does anyone have any clues as to why the above might occur?
Thanks in advance.