Patent ID: 7742488

Claim:
A network device comprising: one or more first ports to receive at least one layer 2 frame of data comprising a media access control (MAC) client data field, wherein the frame of data when received by one of the first ports further comprises a first frame check sequence; an ingress policy module to add M bits to the frame of data before the MAC client data field, where M is an integer greater than zero; a second port to transmit the frame of data after the M bits are added to the frame of data, wherein the ingress policy module, after adding the M bits to the frame of data, and before the second port transmits the frame of data, computes a second frame check sequence for the frame of data and replaces the first frame check sequence in the frame of data with the second frame check sequence; and an egress policy module to remove the M bits from each of the frames of data received by the second port, wherein the egress policy module, after removing the M bits from the frame of data, and before transmitting the frame of data, computes a third frame check sequence for the frame of data and replaces the second frame check sequence in the frame of data with the third frame check sequence.