Patent ID: 8228896

Claim:
A method of verifying the accuracy of a value contained in at least a portion of a header of a layer 2 or layer 'packet formed using a layer 2 or layer 3 protocol, the method comprising the steps of: receiving the layer 2 or layer 3 packet by a router or switch required to make a routing or switching decision for the layer 2 or layer 3 packet using information in a header of the layer 2 or layer 3 packet, the header containing a source address field, a destination address field, a plurality of other header fields, and encrypted signature information, the encrypted signature information relating to at least to a portion of the header including at least the source address field or the destination address field and the encrypted signature information being part of the header of the layer 2 or layer 3 packet when the layer 2 or layer 3 packet is received by the router; comparing, by the router or switch, information associated with the signature information with the portion of the header to determine if the signature information and the portion of the header are consistent to verify the accuracy of a value contained in the portion of the header; and if the information associated with the signature information and the value of the portion of the header are consistent, implementing a quality of service specified by the header in connection with implementing the routing or switching decision for the layer 2 or layer 3 packet; wherein the encrypted signature information is created from fields of the header that are common to a plurality of packets transmitted by a given sender to enable the same encrypted signature information to be used by the sender in connection with transmission of each of the plurality of packets; wherein the encrypted signature information is an encrypted digest of the header information; and wherein the digest is created from a quality of service field, the source address and the destination address.