Apparatus and method of maintaining two-byte IP identification fields in IP headers

• US 20030161312A1
• Filed: 02/27/2002
• Published: 08/28/2003
• Est. Priority Date: 02/27/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Jain, Vinit, Brown, Deanna Lynn Quigg, Venkatsubra, Venkat, Messing, Jeffrey Paul
• Granted Patent: US 7,283,527 B2
• Time in Patent Office: Days
• US Class Current: 370/392
• 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 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 69/168 specially adapted for link layer protocols, e.g. asynchronous transfer mode [ATM], synchronous optical network [SONET] or point-to-point protocol [PPP]

Abstract

A method, system and apparatus for maintaining a two-byte identification field of IP headers when a Gigabit Ethernet is in use are provided. Since the identification field is of two bytes, there is a limited number of identification numbers that may be used. Due to the high data transfer rate of the Gigabit Ethernet, this number may be reached within one second. Hence, there may be a possibility that two or more packets may have the same identification number while in transit. In a representative embodiment, one identification number is used for packets that may not be fragmented. Thus, freeing the rest of the numbers for the packets that may be fragmented. Consequently, before the IP header is added to the packet, a check is made to determine whether the packet may be fragmented. If so, a unique identification number is used in the identification field of the IP header. If not, a non-unique number is used. The non-unique number is used for all packets that may not be fragmented.

Claims

1. A method of maintaining a two-byte identification field of an Internet protocol (IP) header of a packet, the packet being transmitted over a network, the method comprising the steps of:

determining whether the packet is permitted to be fragmented; and

using a non-unique identification number in the IP header if the packet is not permitted to be fragmented.

2. The method of claim 1 wherein the network is a Gigabit Ethernet network.

3. The method of claim 2, wherein a re-assembly timer is set to 30 seconds.

4. The method of claim 3 wherein a bit is set in the IP header to indicate whether the packet is permitted to be fragmented.

5. The method of claim 4 wherein the bit is set in a flag field of the IP header.

6. A computer program product on a computer readable medium for maintaining a two-byte identification field of an Internet protocol (IP) header of a packet, the packet being transmitted over a network, the computer program product comprising:

code means for determining whether the packet is permitted to be fragmented; and

code means for using a non-unique identification number in the IP header if the packet is not permitted to be fragmented.

7. The computer program product of claim 6 wherein the network is a Gigabit Ethernet network.

8. The computer program product of claim 7 wherein a reassembly timer is set to 30 seconds.

9. The computer program product of claim 8 wherein a bit is set in the IP header to indicate whether the packet is permitted to be fragmented.

10. The computer program product of claim 9 wherein the bit is set in a flag field of the IP header.

11. An apparatus for maintaining a two-byte identification field of an Internet protocol (IP) header of a packet, the packet being transmitted over a network, the apparatus comprising:

means for determining whether the packet is permitted to be fragmented; and

means for using a non-unique identification number in the IP header if the packet is not permitted to be fragmented.

12. The apparatus of claim 11 wherein the network is a Gigabit Ethernet network.

13. The apparatus of claim 12 wherein a re-assembly timer is set to 30 seconds.

14. The apparatus of claim 13 wherein a bit is set in the IP header to indicate whether the packet is permitted to be fragmented.

15. The apparatus of claim 14 wherein the bit is set in a flag field of the IP header.

16. A computer system for maintaining a two-byte identification field of an Internet protocol (IP) header of a packet, the packet being transmitted over a network, the computer system comprising:

at least one memory device for storing code data; and

at least one processor for processing the code data to determine whether the packet is permitted to be fragmented and to use a non-unique identification number in the IP header if the packet is not permitted to be fragmented.

17. The computer system of claim 16 wherein the network is a Gigabit Ethernet network.

18. The computer system of claim 17 wherein a re-assembly timer is set to 30 seconds.

19. The computer system of claim 18 wherein a bit is set in the IP header to indicate whether the packet is permitted to be fragmented.

20. The computer system of claim 19 wherein the bit is set in a flag field of the IP header.