Patent ID: 8018862

Claim:
A method comprising: sending an Internet Protocol (IP) request packet comprising a header portion and a payload portion, wherein the header portion contains a first type-of-service indication effecting how the IP packet is to be handled relative to other IP packets; receiving an IP response packet to the IP request packet, the IP response packet containing an indication of a second type-of-service indication in the IP request packet as received by a network device that sent the IP response packet; comparing the first and second type-of-service indications; determining that the IP request packet was re-marked with a different type-of-service indication in the header portion of the IP request packet if the first and second type-of-service indications do not match; and in response to determining that a threshold level of re-marking has been reached, automatically performing an operation to identify a network device that is re-marking the IP request packet, the operation comprising: sending a first request with a first time-to-live indication to a first intermediate network device; comparing a type-of-service indication sent with the first request to a type-of-service indication as received in the first request by the first intermediate device; and determining that the IP request packet was re-marked by a second intermediate device that precedes the first intermediate device if the type-of-service indication sent with the first request does not match the type-of-service indication as received in the first request by the first intermediate device.