We were getting a lot of errors on the input/CRC etc on T3 circuit setup on CE on MPLS site. Upon removing, MTU size of 1500 from serial int config, the errors went away. However, upon show int <serial int>, we see the MTU size of 4470. Where is this new MTU size coming from, is it the provider or some setting on PE? Can someone explain the dynamics of the interface errors. Please let me know.