tmnxPppoePlcyPppMtu 1.3.6.1.4.1.6527.3.1.2.49.1.2.1.5

The value of tmnxPppoePlcyPppMtu specifies the largest IP packet that can be sent out without being fragmented over the specific PPPoE tunnel. A value of 0 indicates the specific MTU is derived from the interface.