Network device that determines application-level network latency by monitoring option values in a transport layer message

摘要

A data processing apparatus in a network receives packet flows that are communicated between a first network node and a second network node, and comprises a clock and latency analysis logic configured for receiving a first data segment that has been communicated from the first node and forwarding the first data segment to the second node; storing a first time value of the clock in association with a first timestamp value obtained from the first data segment; receiving a second data segment that has been communicated from the second node and forwarding the second data segment to the first node; retrieving the first time value based on the first timestamp value; determining a second time value of the clock; and determining a first latency value by computing a difference of the second time value and the first time value. Thus end-to-end packet latency is determined by passively observing timestamp values.