Patent ID: 7668163
Filing Date: 2010-02-23
Classification: H04L

Abstract:
1. A method, comprising: receiving, at a first routing device, a first packet containing a first time-to-live (TTL) value in a header field of the first packet; recording the first TTL value in a second header field of the first packet; forwarding the first packet towards a destination; receiving the first packet at a second routing device; calculating a first delta TTL value from the first TTL value in the first and second header fields of the packet, wherein the first delta TTL represents a hop distance from the first routing device to the second routing device; receiving, at the second routing device, a second packet containing a second TTL value in a first header field of the second packet; recording the second TTL value in a second header field of the second packet; forwarding the second packet towards a destination; receiving the second packet at the first routing device; and calculating a second delta TTL value from the TTL value in the first and second header fields of the second packet, wherein the second delta TTL represents a hop distance from the second routing device to the first routing device.