Measuring packet transmission delays

• US 5,428,616 A
• Filed: 11/23/1992
• Issued: 06/27/1995
• Est. Priority Date: 11/23/1991
• Status: Expired due to Fees

• Current Assignee: CRAY Communications Limited
• Original Assignee: CRAY Communications Limited
• Inventors: Brent, Jason B., Hatala, Edward, Timms, John, Field, Anthony V.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US07/981,940
• Time in Patent Office: 946 Days
• Field of Search: 370/94.1, 370/94.2, 370/94.3, 370/60, 370/108
• US Class Current: 370/253
• CPC Class Codes: H04L 2012/5649 Cell delay or jitter
• CPC Class Codes: H04L 49/206 Real Time traffic
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04Q 11/0478 Provisions for broadband connections

Abstract

A packet transmission system comprising a network of one or more nodes (1) each comprising a number of inputs connected via packet switching means to a number of outputs each of which has storage means (11) associated with it in which to store a queue of packets to be outputted; characterized in that each node (1) is provided with timer means (14) to measure the time each packet spends in a queue of said storage means (11); and stamping means (12) to add to a time stamp field (TS) of each packet before it is outputted from the node, the time the packet has spent in a queue as measured by the timer means (14).

Claims

1. A method of measuring the transmission delay of a packet in a network of a plurality of nodes comprising measuring the time which the packet spends in an output queue of each node and adding this time to a time stamp field of the packet so as to accumulate in said time stamp field a value of the total time spent by the packet in the output queues only of successive nodes across the network.

2. A packet transmission system comprising a network of a plurality of nodes, each node comprising a number of inputs connected via packet switching means to a number of outputs, storage means associated with each output in which to store a queue of packets to be outputted, timer means associated with each output to measure the time each packet spends in a queue of said storage means, and stamping means provided to add to a time stamp field of each packet only that time that the packet has spent in said queue as measured by the timer means before it is outputted from the node so as to accumulate in said time stamp field a value of the total time spent by the packet in output queues only of successive nodes across the network.