A networking device, comprising: a transmitter that is arranged to transmit a data packet to a receiver, the data packet including a data packet header; and a packet header protection generator that is arranged to toggle selected bits of a protected portion of the data packet header and to generate a data integrity signature in response to the protected portion of the data packet header, wherein the data integrity signature is included in an initial portion of the data packet, and wherein the data integrity signature is arranged to allow determination of at least one error in the protected portion of the data packet header, a receiver that is arranged to receive a data packet having a received data integrity signature generated in response to a protected portion of a received data packet header, wherein the protected portion of the received data packet header includes selectively toggled bits; a decoder that is arranged to compute a locally computed data integrity signature in response to the protected portion of the received data packet header, and that is further arranged to compare the locally computed data integrity signature with the received data integrity signature stored in a data packet frame structure, and that is further arranged to perform a responsive action in response to the comparison of the locally computed data integrity signature with the received data integrity signature; characterised in that the networking device comprises a router that is arranged to select a portion of a routing path in response to a determination of whether a data packet forwarding destination includes a decoder that is arranged to compute a locally computed data integrity signature in response to the protected portion of a forwarded data packet header. a transmitter that is arranged to transmit a data packet to a receiver, the data packet including a data packet header; and a packet header protection generator that is arranged to toggle selected bits of a protected portion of the data packet header and to generate a data integrity signature in response to the protected portion of the data packet header, wherein the data integrity signature is included in an initial portion of the data packet, and wherein the data integrity signature is arranged to allow determination of at least one error in the protected portion of the data packet header, a receiver that is arranged to receive a data packet having a received data integrity signature generated in response to a protected portion of a received data packet header, wherein the protected portion of the received data packet header includes selectively toggled bits; a decoder that is arranged to compute a locally computed data integrity signature in response to the protected portion of the received data packet header, and that is further arranged to compare the locally computed data integrity signature with the received data integrity signature stored in a data packet frame structure, and that is further arranged to perform a responsive action in response to the comparison of the locally computed data integrity signature with the received data integrity signature; characterised in that the networking device comprises a router that is arranged to select a portion of a routing path in response to a determination of whether a data packet forwarding destination includes a decoder that is arranged to compute a locally computed data integrity signature in response to the protected portion of a forwarded data packet header. <EOS>