Method, system and article for improved network performance by avoiding IP-ID wrap-arounds causing data corruption on fast networks

• US 20060133365A1
• Filed: 12/16/2004
• Published: 06/22/2006
• Est. Priority Date: 12/16/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Vallabhaneni, Vasu, Venkatsubra, Venkat, Youngman, Richard Perry, Manjunatha, Shankar
• Granted Patent: US 7,564,843 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols

Abstract

The reassembly timer in a TCP/IP receiver is dynamically set to avoid data corruption on fast networks caused by IP identification wrap-around. A sender generates IP packets with a special option specifying a reassembly time for fragments based on the subnet of the destination or on the calculated round-trip time of the connection. A receiver sets the reassembly timer to the reassembly time specified in the option. A sender can generate IP packets with an alternative option setting a time stamp for the generated packet. A receiver calculates a traversal time based on the difference between the arrival time of the fragment and this time stamp, and sets the reassembly timer based on this traversal time.

Claims

1. A method for communication over a data processing system network comprising:

determining a customized reassembly time for a particular data packet to be transmitted;

generating the data packet, including inserting the customized reassembly time into a field of the data packet; and

transmitting the data packet, wherein a receiver of the data packet will utilize the customized reassembly time to discard a fragment of the packet that remains fragmented longer than indicated by the customized reassembly time following receipt of the fragment.

2. The method according to claim 1, wherein the step of determining a customized reassembly time includes setting the customized reassembly time to a first time if a sender of the data packet is connected to the receiver over a known fast link of the network and to a second time if the sender of the data packet is not connected to the receiver over a known fast link of the network.

3. The method according to claim 2, wherein the sender of the data packet is connected to the receiver over a known fast link of the network when the sender is within a same subnet of the network as the receiver of the data packet.

4. The method according to claim 1, wherein the step of determining a customized reassembly time includes setting the customized reassembly time to a computed round-trip time for a data packet transmitted from a sender to the receiver.

5. The method according to claim 4, wherein the round-trip time is the RTT computed by a TCP layer.

6. The method according to claim 1, wherein the data packet is an IP packet generated by an IP layer.

7. The method according to claim 1, wherein the customized reassembly time is a time stamp specifying a time when the data packet is generated, and wherein the receiver of the data packet will utilize the customized reassembly time to compute a traversal time of the data fragment based on the arrival time of the data fragment, and further wherein the receiver sets a reassembly time for the data fragment based on the traversal time.

8. The method according to claim 1, wherein the step of generating the data packet comprises setting an option in a header of the data packet specifying a reassembly time.

9. The method according to claim 1, wherein the step of generating the data packet comprises setting an option in a header of the data packet with a time stamp specifying a time of generating the data packet.

10. A data processing system comprising:

means for determining a customized reassembly time for a particular data packet to be transmitted;

means for generating the data packet, including inserting the customized reassembly time into a field of the data packet; and

means for transmitting the data packet, wherein a receiver of the data packet will utilize the customized reassembly time to discard a fragment of the packet that remains fragmented longer than indicated by the customized reassembly time following receipt of the fragment.

11. The system according to claim 10, further comprising means for setting the customized reassembly time to a first time if a sender of the data packet is connected to the receiver over a known fast link of the network and to a second time if the sender of the data packet is not connected to the receiver over a known fast link of the network.

12. The system according to claim 11, wherein the sender of the data packet is connected to the receiver over a known fast link of the network when the sender is within a same subnet of the network as the receiver of the data packet.

13. The system according to claim 10, further comprising means for setting the customized reassembly time to a computed round-trip time for a data packet transmitted from a sender to the receiver.

14. The system according to claim 13, wherein the round-trip time is the RTT computed by a TCP layer.

15. The system according to claim 10, wherein the data packet is an IP packet generated by an IP layer.

16. The system according to claim 10, wherein the customized reassembly time is a time stamp specifying a time when the data packet is generated, and wherein the receiver of the data packet will utilize the customized reassembly time to compute a traversal time of the data fragment based on the arrival time of the data fragment, and further wherein the receiver sets a reassembly time for the data fragment based on the traversal time.

17. The system according to claim 10, further comprising means for setting an option in a header of the data packet specifying a reassembly time.

18. The system according to claim 10, further comprising means for setting an option in a header of the data packet with a time stamp specifying a time of generating the data packet.

19. An article of manufacture comprising machine-readable medium including program logic embedded therein for communication over a data processing system network that causes control circuitry in a data processing system to perform the steps of:

determining a customized reassembly time for a particular data packet to be transmitted;

generating the data packet, including inserting the customized reassembly time into a field of the data packet; and

transmitting the data packet, wherein a receiver of the data packet will utilize the customized reassembly time to discard a fragment of the packet that remains fragmented longer than indicated by the customized reassembly time following receipt of the fragment.

20. The article of manufacture according to claim 19, wherein the step of determining a customized reassembly time includes setting the customized reassembly time to a first time if a sender of the data packet is connected to the receiver over a known fast link of the network and to a second time if the sender of the data packet is not connected to the receiver over a known fast link of the network.

21. The article of manufacture according to claim 20, wherein the sender of the data packet is connected to the receiver over a known fast link of the network when the sender is within a same subnet of the network as the receiver of the data packet.

22. The article of manufacture according to claim 19, wherein the step of determining a customized reassembly time includes setting the customized reassembly time to a computed round-trip time for a data packet transmitted from a sender to the receiver.

23. The article of manufacture according to claim 22, wherein the round-trip time is the RTT computed by a TCP layer.

24. The article of manufacture according to claim 19, wherein the data packet is an IP packet generated by an IP layer.

25. The article of manufacture according to claim 19, wherein the customized reassembly time is a time stamp specifying a time when the data packet is generated, and wherein the receiver of the data packet will utilize the customized reassembly time to compute a traversal time of the data fragment based on the arrival time of the data fragment, and further wherein the receiver sets a reassembly time for the data fragment based on the traversal time.

26. The article of manufacture according to claim 19, wherein the step of generating the data packet comprises setting an option in a header of the data packet specifying a reassembly time.

27. The article of manufacture according to claim 19, wherein the step of generating the data packet comprises setting an option in a header of the data packet with a time stamp specifying a time of generating the data packet.

28. A method in a data processing system network comprising:

receiving a data fragment over a network containing an option indicating a customized reassembly time for a data packet comprising the data fragment; and

discarding the data fragment if it remains fragmented from the data packet longer than indicated by the customized reassembly time following receipt of the data fragment.

29. The method according to claim 28, wherein the option specifies the customized reassembly time in a field of the data fragment.

30. The method according to claim 28, wherein the option specifies a time stamp of when the data packet was generated by a sender, and further comprising computing a traversal time for the data fragment as a function of the time stamp and a time that the data fragment arrives at the receiver, and further specifying a reassembly time for the data fragment based on the traversal time.

31. The method according to claim 28, wherein the data packet is an IP packet generated by an IP layer.

32. The method according to claim 28, wherein the customized reassembly timer is used to indicate the reassembly time for all data fragments of the data packet.

33. The method according to claim 28, wherein the customized reassembly timer is used to set a reassembly time in the receiver if the customized reassembly timer indicates a reassembly time longer than a currently-used reassembly time in the receiving system.

34. A data processing system comprising:

means for receiving a data fragment over a network containing an option indicating a customized reassembly time for a data packet comprising the data fragment; and

means for discarding the data fragment if it remains fragmented from the data packet longer than indicated by the customized reassembly time following receipt of the data fragment.

35. The system according to claim 34, wherein the option specifies the customized reassembly time in a field of the data fragment.

36. The system according to claim 34, wherein the option specifies a time stamp of when the data packet was generated by a sender, and further comprising means for computing a traversal time for the data fragment as a function of the time stamp and a time that the data fragment arrives at the receiver, and further specifying a reassembly time for the data fragment based on the traversal time.

37. The system according to claim 34, wherein the data packet is an IP packet generated by an IP layer.

38. The system according to claim 34, wherein the customized reassembly timer is used to indicate the reassembly time for all data fragments of the data packet.

39. The system according to claim 34, wherein the customized reassembly timer is used to set a reassembly time in the receiver if the customized reassembly timer indicates a reassembly time longer than a currently-used reassembly time in the receiving system.

40. An article of manufacture comprising machine-readable medium including program logic embedded therein that causes control circuitry in a data processing system to perform the steps of:

receiving a data fragment over a network containing an option indicating a customized reassembly time for a data packet comprising the data fragment; and

discarding the data fragment if it remains fragmented from the data packet longer than indicated by the customized reassembly time following receipt of the data fragment.

41. The article of manufacture according to claim 40, wherein the option specifies the customized reassembly time in a field of the data fragment.

42. The article of manufacture according to claim 40, wherein the option specifies a time stamp of when the data packet was generated by a sender, and further comprising computing a traversal time for the data fragment as a function of the time stamp and a time that the data fragment arrives at the receiver, and further specifying a reassembly time for the data fragment-based on the traversal time.

43. The article of manufacture according to claim 40, wherein the data packet is an IP packet generated by an IP layer.

44. The article of manufacture according to claim 40, wherein the customized reassembly timer is used to indicate the reassembly time for all data fragments of the data packet.

45. The article of manufacture according to claim 40, wherein the customized reassembly timer is used to set a reassembly time in the receiver if the customized reassembly timer indicates a reassembly time longer than a currently-used reassembly time in the receiving system.