Patent ID: 8068429

Claim:
A traffic generator for providing a packet stream to measure jitter of a network under test, the traffic generator comprising: at least one packet generator to generate scheduled and unscheduled packets; a transmit scheduler comprising: at least one scheduled traffic queue for holding scheduled packets generated by the at least one packet generator, a first transmit time store for storing scheduled transmit times associated respectively with the scheduled packets held in the at least one scheduled traffic queue, at least one unscheduled traffic queue for holding unscheduled packets generated by the at least one packet generator, and a packet selector coupled to the at least one scheduled traffic queue, the transmit time store, and the at least one unscheduled traffic queue; a packet processor that receives scheduled and unscheduled packets from the packet selector and processes the received packets prior to transmission; and a physical interface unit that transmits packets from the packet processor over an interface, wherein the packet selector provides scheduled packets to the packet processor in advance of the respective scheduled transmit times by an amount equal to a latency of the packet processor and the physical interface unit, such that each scheduled packet is transmitted at the respective scheduled transmit time within a tolerance that is smaller than an anticipated jitter of the network under test, and the packet selector causes transmission of unscheduled packets during time intervals between transmissions of scheduled packets.