We have a LES 100 Worldcom service and have been running it as a point-to-point link between 2 x 3600 routers. We needed to add a second routed network and therefore inserted 2xCat3550's on the ends of the LES. Trunking was configured between 3550's. With trunking turned on routing protocol adjacencies could be seen to drop periodically. We belive it's an MTU issues with the Worldcom circuit as it behaves abnormally when we configure ISL or 802.1Q. If the switch ports at either end of the LES are configured as access ports then there is no issue.
Has anybody seen this issue and is it MTU and if so is there a workaround
