Abstract: A data processing apparatus comprises instructions to perform sending and receiving one or more messages conforming to a network routing protocol, such as Open Shortest Path First (OSPF); obtaining one or more information elements that specify one or more capabilities of the apparatus; creating a particular routing protocol message comprising an opaque advertisement that includes the one or more information elements; and sending the particular message on one of the network interfaces. For example, a router or switch that implements a network routing protocol can use OSPF Opaque Link State Advertisements to advertise and discover services and capabilities of other routers or switches.

Abstract: 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.