Method and system for processing fragments and their out-of-order delivery during address translation

• US 6,944,672 B2
• Filed: 06/17/2002
• Issued: 09/13/2005
• Est. Priority Date: 01/07/1999
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Crow, James J., McClanahan, Kip R., Rao, Satyanarayana B.
• Primary Examiner(s): Najjar, Saleh
• Application Number:
  US10/174,360
• Publication Number:
  US 20020161915A1
• Time in Patent Office: 1,184 Days
• Field of Search: 709/230, 709/235, 709/236, 709/238, 709/242, 709/245, 370/473, 370/474, 370/475, 370/476, 359/117, 379/219
• US Class Current: 709/236
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2517 using port numbers
• 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 69/166 IP fragmentation; TCP segmentation
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A set of packetized fragments in which only a portion of the fragments carry translation information for the set of fragments is translated by storing in a memory fragments received before the translation information. In response to receiving the translation information, the fragments stored in the memory are translated based on the translation information. After receipt of the translation information, fragments are translated as they are received based on the translation information.

Claims

1. A system for translating a set of packetized fragments in which only a portion of the fragments carry translation information for the set of fragments, comprising:

a memory operable to store fragments received before the translation information; and

a translation engine operable to;

receive the translation information in one or more fragments;

translate the fragments comprising translation information and the fragments stored in the memory based on the translation information; and

after receipt of the translation information, translate fragments not stored in the memory as they are received, based on the translation information;

wherein at least one fragment that does not carry translation information includes first data and at least one fragment that carries translation information includes second data, and wherein the first data and the second data together form at least a portion of a complete message.

2. The system of claim 1, wherein the translation information is address translation information and each fragment is translated by translating addressing information for the fragment.

3. The system of claim 1, wherein the translation information is address translation information and each fragment is translated in accordance with a translation system selected from the group consisting of network address translation (NAT) and port address translation (PAT).

4. The system of claim 1, wherein the fragments comprise Internet Protocol (IP) packets.

5. A method for translating addressing information for a set of packetized fragments including a primary fragment having address translation information for the set of fragments and a plurality of secondary fragments without address translation information, comprising:

storing in a memory a first plurality of secondary fragments received before the primary fragment, wherein at least one of the first plurality of secondary fragments comprises first payload data;

receiving the primary fragment comprising address translation information and second payload data;

translating the first plurality of secondary fragments based on the address translation information;

receiving a second plurality of secondary fragments after receiving the primary fragment, wherein at least one of the second plurality of secondary fragments comprises third payload data; and

translating the second plurality of secondary fragments based on the address translation information;

wherein the first payload data, the second payload data, and the third payload data together form at least a portion of a complete message.

6. The method of claim 5, further comprising translating addressing information for the primary fragment based on the address translation information.

7. The method of claim 5, wherein each fragment is translated in accordance with a translation system selected from the group consisting of network address translation (NAT) and port address translation (PAT).

8. The method of claim 5, further comprising generating, based on the address translation information of the primary fragment, a fragment-context for translating addressing information for the secondary fragments.

9. The method of claim 8, further comprising translating addressing information for the first plurality of secondary fragments using the fragment-context.

10. The method of claim 5, further comprising deleting the first plurality of secondary fragments from the memory if the primary fragment is not received within a specified period of time.

11. The method of claim 5, wherein the fragments comprise Internet Protocol (IP) packets.

12. The method of claim 5, wherein each secondary fragment is translated by translating addressing information for the secondary fragment.

13. A system for translating addressing information for a set of packetized fragments including a primary fragment having address translation information for the set of fragments and a plurality of secondary fragments without address translation information, comprising:

a memory operable to store a first plurality of secondary fragments received before the primary fragment, wherein at least one of the first plurality of secondary fragments comprises first payload data; and

a translation engine operable to;

receive the primary fragment comprising address translation information and second payload data;

translate the first plurality of secondary fragments based on the address translation information;

receive a second plurality of secondary fragments after receiving the primary fragment, wherein at least one of the second plurality of secondary fragments comprises third payload data; and

translate the second plurality of secondary fragments based on the address translation information;

wherein the first payload data, the second payload data, and the third payload data together form at least a portion of a complete message.

14. The system of claim 13, wherein the translation engine is further operable to translate addressing information for the primary fragment based on the address translation information.

15. The system of claim 13, wherein each fragment is translated in accordance with a translation system selected from the group consisting of network address translation (NAT) and port address translation (PAT).

16. The system of claim 13, wherein the translation engine is further operable to generate, based on the address translation information of the primary fragment, a fragment-context for translating addressing information for the secondary fragments.

17. The system of claim 16, wherein the translation engine is further operable to translate addressing information for at least a portion of the secondary fragments using the fragment-context.

18. The system of claim 13, wherein the translation engine is further operable to delete the first plurality of secondary fragments from the memory if the primary fragment is not received within a specified period of time.

19. The system of claim 13, wherein the fragments comprise Internet Protocol (IP) packets.

20. The system of claim 13, wherein each secondary fragment is translated by translating addressing information for the secondary fragment.