Patent ID: 9509582
Filing Date: 2016-11-29
CPC Classification: H04L

Claim Text:
1. A method for measuring a resident time of a probe message in a first network node included in a network path, the probe message provided with a Time-To-Live value, the method comprising: registering a receive timestamp of the probe message upon receipt of the probe message detected by one of a plurality of protocol stacks in the first network node; writing the receive timestamp to a dedicated field within the probe message; checking the Time-To-Live value of the probe message; decrementing the Time-To-Live value by one if the Time-To-Live value is neither one nor null; if the Time-To-Live value is equal to one, then registering a transmit timestamp of the probe message, the transmit timestamp corresponding to a time instant at which the probe message leaves the one of the plurality of protocol stacks for transmission, computing the resident time of the probe message within the first network node by subtracting the receive timestamp from the transmit timestamp, writing the computed resident time to the dedicated field within the probe message, determining if an error exists in the probe message, the error corresponding to failing to decrement the TTL value or having set at least one flag in the probe message in error by a second network node prior to forwarding of the probe message from the second network node to the first network node, changing a value of the at least one flag within the probe message in order to protect the computed resident time from being over written by subsequent actions on the probe message if the error does not exist, and sending, to the second network node, a first timestamp reply message with an outgoing resident time field set to null and the at least one flag set to one, if the error exists; and if the Time-To-Live value is equal to null, then sending a second timestamp reply message to the second network node when the first network node is a destination node, the second timestamp reply message including an outgoing resident time field, and sending an error message to the second network node, the error message including a Time-to-Live Exceed message when the first network node is not the destination node.