Wrap-around route testing in packet communications networks

• US 5,563,875 A
• Filed: 07/10/1995
• Issued: 10/08/1996
• Est. Priority Date: 07/10/1995
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: McSweeney, Thomas P., Hefel, Timothy R., Huynh, Lap T.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): PHILLIPS, MATTHEW
• Application Number:
  US08/500,674
• Time in Patent Office: 456 Days
• Field of Search: 370/15, 370/14, 370/13, 370/13.1, 379/5, 371/20.5
• US Class Current: 370/249
• CPC Class Codes: H04L 43/50 Testing arrangements
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/123 Evaluation of link metrics techniques for monitoring network metrics H04L43/08

Abstract

A packet communications network includes a route testing system which launches a plurality of route testing messages from the source node to each of the nodes along the route, including the destination node, and returning to the source node. Time stamps in each of theses testing messages are compared to reception times to determine round trip delays which can be halved and compared to determine link transit times. These link transit times can, in turn, be analyzed to localize congestion or identify failed resources. The source resource is where the data is accumulated for the entire path and then analyzed to determine the location of failed links, if any, the response time from the source to the destination, the response time of each resource in the path, and the location of congested links. Packet switched resources identify the path test command themselves and carry out the testing procedure. Circuit switched resources utilize the control point controlling that resource to carry out the testing procedure.

Claims

1. A packet communications network comprising

a plurality of network resources interconnected by transmission links;

means for determining at least one route through said network from a source resource to a destination resource in said network;

means for launching a wrap-around route testing messages on said network to said destination resource;

means for launching one or more wrap-around route testing messages on said network, one such route testing message for each of said resources in said route between said source resource and said destination resource;

means at said source resource for receiving each of said route testing messages; and

means at said source resource for processing said route testing messages.

2. A packet transmission network according to claim 1 further comprising

means in said source resource for inserting the current time in each of said route testing messages.

3. The network according to claim 1 further comprising

means at said source resource for storing information concerning said wrap-around route testing messages.

4. The network according to claim 1 further comprising

means at said source resource for displaying information concerning said wrap-around route testing messages.

5. The network according to claim 1 wherein said processing means comprises

means for determining transit times to each of said resources in said route equal to one-half of the difference between the transmission time and the reception time of corresponding ones of said route testing messages.

6. The network according to claim 5 wherein said processing means further comprises

means for determining the difference between said transit times for adjacent ones of said resources in said route.

7. The network according to claim 1 further comprising

means for identifying failed ones of said resources.

8. A method for operating a packet communications network comprising the steps of

interconnecting a plurality of network resources by a plurality of transmission links;

determining at least one route through said network from a source resource to a destination resource in said network;

launching a wrap-around route testing message onto said route to said destination resource;

launching one or more wrap-around route testing messages onto said route, one such route testing message for each of said resources in said route between said source resource and said destination resource;

receiving at said source resource each of said route testing messages; and

processing said route testing messages at said source resource.

9. The method according to claim 8 further comprising the step of

inserting the current time in each of said route testing messages at said source resource.

10. The method according to claim 8 further comprising the step of

storing information concerning said wrap-around route testing messages at said source resource.

11. The method according to claim 8 further comprising the steps of

displaying information concerning said wrap-around route testing messages at said source resource.

12. The method according to claim 8 wherein said processing step further comprises the step of

determining transit times to each of said resources in said route equal to one-half of the difference between the transmission time and the reception time of corresponding ones of said route testing messages.

13. The method according to claim 12 wherein said processing step further comprises the step of

determining the difference between said transit times for adjacent ones of said resources in said route.

14. The method according to claim 8 further comprising the step of

identifying failed ones of said resources.

15. A route testing system for a packet communications network including a plurality of resources and utilizing pre-calculated routes through said network, said testing system being located at one of said resources and comprising

means for launching a wrap-around route testing message on said network to the resource at the end of said route;

means for launching one or more wrap-around route testing messages on said network, one such route testing message for each of said resources in said route;

means for receiving each of said route testing messages; and

means for processing said route testing messages.

16. A testing system according to claim 15 further comprising

means for inserting the current time in each of said route testing messages.

17. The testing system according to claim 15 further comprising

means for storing information concerning said wrap-around route testing messages.

18. The testing system according to claim 15 further comprising

means for displaying information concerning said wrap-around route testing messages.

19. The testing system according to claim 15 wherein said processing means comprises

means for determining transit times to each of said resources in said route equal to one-half of the difference between the transmission time and the reception time of corresponding ones of said route testing messages.

20. The testing system according to claim 19 wherein said processing means further comprises

means for determining the difference between said transit times for adjacent ones of said resources in said route.

21. The testing system according to claim 15 further comprising

means for identifying failed ones of said resources.