Method and apparatus for identifying a maximum frame size

• US 6,909,697 B1
• Filed: 02/06/2001
• Issued: 06/21/2005
• Est. Priority Date: 12/22/1997
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Langley, David
• Primary Examiner(s): Duong, Frank
• Application Number:
  US09/778,246
• Time in Patent Office: 1,596 Days
• Field of Search: 370/230, 370/231, 370/232, 370/235, 370/236, 370/229, 370/252, 370/253, 370/470, 370/471, 370/474
• US Class Current: 370/252
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/16 in connection oriented networks, e.g. frame relay
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]

Abstract

A method and apparatus negotiates a maximum frame size to be used over a frame relay network. A local maximum frame size is identified by a first endpoint device of a frame relay network so that other frames sent and received using that size will not cause other frames sent by the network device to be sent a period of time exceeding an acceptable delay after the other frames are received. The acceptable delay is the lowest acceptable delay among originators and recipients of frames that use the endpoint device. The frame size identified is transmitted to other endpoint devices that can communicate with the first endpoint device. These other endpoint devices identify acceptable delays that correspond to the originators and recipients of such endpoint devices.

Claims

1. A computer-implemented method for determining a maximum frame size for an endpoint device in a frame relay network, the method comprising:

selecting a shortest acceptable delay value from two or more acceptable delay values associated with two or more originating network devices that use the endpoint device to send information over the frame relay network; and

determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device.

2. The method as recited in claim 1, wherein determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device includes determining a product of the shortest acceptable delay value and the speed value.

3. The method as recited in claim 2, further comprising providing the maximum frame size for the endpoint device to the two or more originating network devices.

4. The method as recited in claim 3, further comprising transmitting the maximum frame size for the endpoint device to the two or more originating network devices in a frame size message.

5. The method as recited in claim 1, further comprising transmitting the maximum frame size for the endpoint device to a second endpoint device from which the endpoint device might receive data.

6. The method as recited in claim 1, further comprising:

receiving a second maximum frame size from a second endpoint device;

selecting a first smallest maximum frame size based upon the smaller of the first maximum frame size and the second maximum frame size; and

using the selected first smallest maximum frame size for transmitting data from the endpoint device to the second endpoint device.

7. The method as recited in claim 6, further comprising:

receiving a third maximum frame size from a third endpoint device;

selecting a second smallest maximum frame size based upon the smaller of the first maximum frame size and the third maximum frame size; and

using the selected second smallest maximum frame size for transmitting data from the endpoint device to the third endpoint device.

8. The method as recited in claim 1, further comprising determining an adjusted maximum frame size by subtracting a specified value from the determined maximum frame size, wherein the specified value reflects processing delays in the endpoint device.

9. The method as recited in claim 1, wherein each of the two or more acceptable delay values is associated with a PVC.

10. The method as recited in claim 1, wherein the selecting and determining steps are performed at the endpoint device.

11. A computer-readable medium for determining a maximum frame size for an endpoint device in a frame relay network, the computer-readable medium carrying instructions which, when executed by one or more processors, cause:

selecting a shortest acceptable delay value from two or more acceptable delay values associated with two or more originating network devices that use the endpoint device to send information over the frame relay network; and

determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device.

12. The computer-readable medium as recited in claim 11, wherein determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device includes determining a product of the shortest acceptable delay value and the speed value.

13. The computer-readable medium as recited in claim 12, further comprising additional instructions which, when executed by the one or more processors, cause providing the maximum frame size for the endpoint device to the two or more originating network devices.

14. The computer-readable medium as recited in claim 13, further comprising additional instructions which, when executed by the one or more processors, cause transmitting the maximum frame size for the endpoint device to the two or more originating network devices in a frame size message.

15. The computer-readable medium as recited in claim 11, further comprising additional instructions which, when executed by the one or more processors, cause transmitting the maximum frame size for the endpoint device to a second endpoint device from which the endpoint device might receive data.

16. The computer-readable medium as recited in claim 11, further comprising additional instructions which, when executed by the one or more processors, cause:

receiving a second maximum frame size from a second endpoint device;

selecting a first smallest maximum frame size based upon the smaller of the first maximum frame size and the second maximum frame size; and

using the selected first smallest maximum frame size for transmitting data from the endpoint device to the second endpoint device.

17. The computer-readable medium as recited in claim 16, further comprising additional instructions which, when executed by the one or more processors, cause:

receiving a third maximum frame size from a third endpoint device;

selecting a second smallest maximum frame size based upon the smaller of the first maximum frame size and the third maximum frame size; and

using the selected second smallest maximum frame size for transmitting data from the endpoint device to the third endpoint device.

18. The computer-readable medium as recited in claim 11, further comprising additional instructions which, when executed by the one or more processors, cause determining an adjusted maximum frame size by subtracting a specified value from the determined maximum frame size, wherein the specified value reflects processing delays in the endpoint device.

19. The computer-readable medium as recited in claim 11, wherein each of the two or more acceptable delay values is associated with a PVC.

20. The computer-readable medium as recited in claim 11, wherein the selecting and determining steps are performed at the endpoint device.

21. An apparatus for determining a maximum frame size for an endpoint device in a frame relay network, the apparatus comprising a memory storing instructions which, when executed by one or more processors, cause:

selecting a shortest acceptable delay value from two or more acceptable delay values associated with two or more originating network devices that use the endpoint device to send information over the frame relay network; and

determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device.

22. The apparatus as recited in claim 21, wherein determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device includes determining a product of the shortest acceptable delay value and the speed value.

23. The apparatus as recited in claim 22, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause providing the maximum frame size for the endpoint device to the two or more originating network devices.

24. The apparatus as recited in claim 23, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause transmitting the maximum frame size for the endpoint device to the two or more originating network devices in a frame size message.

25. The apparatus as recited in claim 21, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause transmitting the maximum frame size for the endpoint device to a second endpoint device from which the endpoint device might receive data.

26. The apparatus as recited in claim 21, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause:

receiving a second maximum frame size from a second endpoint device;

selecting a first smallest maximum frame size based upon the smaller of the first maximum frame size and the second maximum frame size; and

using the selected first smallest maximum frame size for transmitting data from the endpoint device to the second endpoint device.

27. The apparatus as recited in claim 26, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause:

receiving a third maximum frame size from a third endpoint device;

selecting a second smallest maximum frame size based upon the smaller of the first maximum frame size and the third maximum frame size; and

using the selected second smallest maximum frame size for transmitting data from the endpoint device to the third endpoint device.

28. The apparatus as recited in claim 21, wherein the memory further comprises additional instructions which, when executed by the one or more processors, cause determining an adjusted maximum frame size by subtracting a specified value from the determined maximum frame size, wherein the specified value reflects processing delays in the endpoint device.

29. The apparatus as recited in claim 21, wherein each of the two or more acceptable delay values is associated with a PVC.

30. The apparatus as recited in claim 21, wherein the apparatus is the endpoint device.

31. An apparatus for determining a maximum frame size for an endpoint device in a frame relay network, the apparatus comprising:

means for selecting a shortest acceptable delay value from two or more acceptable delay values associated with two or more originating network devices that use the endpoint device to send information over the frame relay network; and

means for determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device.

32. The apparatus as recited in claim 31, wherein the means for determining the maximum frame size for the endpoint device based upon the selected shortest acceptable delay value and a speed value of a physical connection connected to the endpoint device includes means for determining a product of the shortest acceptable delay value and the speed value.

33. The apparatus as recited in claim 32, further comprising means for providing the maximum frame size for the endpoint device to the two or more originating network devices.

34. The apparatus as recited in claim 33, further comprising means for transmitting the maximum frame size for the endpoint device to the two or more originating network devices in a frame size message.

35. The apparatus as recited in claim 31, further comprising means for transmitting the maximum frame size for the endpoint device to a second endpoint device from which the endpoint device might receive data.

36. The apparatus as recited in claim 31, further comprising:

means for receiving a second maximum frame size from a second endpoint device;

means for selecting a first smallest maximum frame size based upon the smaller of the first maximum frame size and the second maximum frame size; and

means for using the selected first smallest maximum frame size for transmitting data from the endpoint device to the second endpoint device.

37. The apparatus as recited in claim 36, further comprising:

means for receiving a third maximum frame size from a third endpoint device;

means for selecting a second smallest maximum frame size based upon the smaller of the first maximum frame size and the third maximum frame size; and

means for using the selected second smallest maximum frame size for transmitting data from the endpoint device to the third endpoint device.

38. The apparatus as recited in claim 31, further comprising means for determining an adjusted maximum frame size by subtracting a specified value from the determined maximum frame size, wherein the specified value reflects processing delays in the endpoint device.

39. The apparatus as recited in claim 31, wherein each of the two or more acceptable delay values is associated with a PVC.

40. The apparatus as recited in claim 31, wherein the apparatus is the endpoint device.