Implicit packet type identification

• US 7,289,497 B2
• Filed: 04/15/2002
• Issued: 10/30/2007
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Pelletier, Ghyslain, Jonsson, Lars-Erik
• Primary Examiner(s): Patel; Ajit
• Application Number:
  US10/124,088
• Publication Number:
  US 20030009663A1
• Time in Patent Office: 2,024 Days
• Field of Search: 370/466, 370/467, 370/468, 370/389, 370/254, 370/152, 370/349, 370/338, 370/392, 370/477, 370/521
• US Class Current: 370/389
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC

Abstract

In a system for transmitting packets over a link between a compressor and a decompressor, a method is provided for implicit packet type identification. A set of implicit packet transmission characteristics including at least first and second characteristics is selected, and the compressor is operated to assign the first and second transmission characteristics to packets of first and second packet types, respectively. The decompressor is operated to detect transmission characteristics of packets received by the decompressor, and to thereby identify a received packet as being either a first or second packet type. Usefully, header free packets comprise one of the packet types.

Claims

1. In a system for transmitting packets over a link between a compressor and a decompressor, a method of implicit packet type identification comprising the steps of:

selecting a set of implicit packet transmission characteristics, comprising at least first and second distinguishably different transmission characteristics and further selecting a number of specific packet sizes for use only with header free packets, wherein said compressor uses one of said specific packet sizes to transmit only header free packets;

operating said compressor to

compress a header of a first packet type so that the first packet type becomes header free and to

assign said first transmission characteristic to packets of the first packet type, the compressor further operating to assign said second transmission characteristic to packets of a second packet type which is different from said first packet type; and

operating said decompressor to detect said transmission characteristics of packets received by said decompressor, and to thereby identify a received packet as being either the first packet type or the second packet type.

2. The method of claim 1 wherein said selecting step comprises a pre-negotiation between said compressor and said decompressor.

3. The method of claim 1 wherein said selecting step comprises selecting different packet sizes for said first and second packet types.

4. The method of claim 1 wherein said selecting step comprises selecting different sets of channel coding combinations for said first and second packet types.

5. The method of claim 1 wherein said selecting step comprises selecting multiplexing options to create different logical channels for said first and second packet types.

6. The method of claim 1 wherein said selecting step comprises selection of a set of encryption keys with an encryption algorithm, and said compressor assigning different encryption keys to said first and second packet types.

7. The method of claim 1 wherein said system is disposed to compress and decompress packet headers in accordance with a scheme selected from a group of header compression/decompression schemes comprising [VJ], [IPHC], [CRTP], [LLA] and [ROHC].

8. The method of claim 1 wherein said selecting step comprises selecting N different packet transmission characteristics for respectively identifying the packets of N different packet types.

9. The method of claim 1 wherein said second packet type comprises packets which have headers.

21. The system of claim 1 wherein said compressor assigns different encryption keys to said first and second packet types from a set of encryption keys that are determined utilizing an encryption algorithm.

10. In a system for transmitting packets over a link between a compressor and decompressor, which respectively compresses packet headers before and decompresses packet headers after transmission, a method of implicit packet type identification comprising the steps of:

selecting a set of implicit packet transmission characteristics, wherein different characteristics of said set of implicit packet transmission characteristics identify packets of different types and further selecting a number of specific packetsizes for use only with header free packets, wherein said compresser uses one of said specific packet sizes to transmit only header free packets;

compressing the header of a particular packet so that said particular packet becomes header free, said particular packet being of a type identified by a corresponding one of said characteristics;

transmitting said particular packet over said link from said compressor to said decompressor; and

operating said decompressor to detect said corresponding characteristic and to thereby identify said particular packet as being a header free packet type.

11. The method of claim 10 wherein:

said selecting step comprises selecting a set of channel coding combinations; and

one of said channel coding combinations is assigned only to header free packets and another of said channel coding combinations is assigned only to packets of another specified type.

12. The method of claim 10 wherein:

said selecting step comprises selecting multiplexing options to create different logical channels, only header free packets being sent on one of said logical channels, and only packets of another specified type being sent on another of said logical channels.

13. The method of claim 10 wherein:

said selecting step comprises selection of a set of encryption keys with an encryption algorithm, one of said keys being assigned only to header free packets, and another of said keys being assigned only to packets of another specified type.

14. The method of claim 10 wherein:

said selecting step comprises a pre-negotiation between said compressor and said decompressor.

15. A system for transmitting packets over a link comprising:

a compressor for compressing a header of a first packet type so that the first packet type becomes header free and for assigning a first transmission characteristic from a set of implicit packet transmission to packets of the first packet type, and to assign a second transmission characteristic to packets of a second packet type which is different from said first packet type,

means for selecting a number of specific packet sizes for use only with header free packets where said compresser uses one of said specific packet sizes to transmit only header free packets; and

a decompressor at the opposing side of said link disposed to detect said transmission characteristics of packets received by said decompressor. and to thereby identify a received packet as being either said first packet type or said secondpacket type.

16. The system of claim 15 wherein said compressor and said decompressor pre-negotiate packet characteristics.

17. The system of claim 15 wherein, and said second packet type comprises packets with headers.

18. The method of claim 15 wherein said compressor assigns different packet sizes for said first and second packet types.

19. The method of claim 15 wherein different sets of channel coding combinations are assigned for said first and second packet types.

20. The system of claim 15 further comprising means for selecting multiplexing options to create different logical channels wherein said first and second packet types are each sent on a different logical channel.

22. In a system for transmitting packets over a link between a compressor and an opposite party, a method of implicit packet type identification comprising the steps of:

selecting a number of specific packet sizes for use only with header free packets, wherein said compresser uses one of said specific packet sizes to transmit only header free packets;

selecting a set of implicit packet transmission characteristics, comprising at least first and second distinguishably different transmission characteristics;

compressing the header of a first packet type so that the first packet type becomes header free and assigning the first transmission characteristic to packets of a first packet type; and

assigning said second characteristic to packets of a second packet type which is different from said first packet type.

23. The method of claim 22 wherein said selecting step comprises a pre-negotiation between said compressor and said opposite party.

24. The method of claim 22 wherein said selecting step comprises selecting different packet sizes for said first and second packet types.

25. The method of claim 22 wherein said selecting step comprises selecting different sets of channel coding combinations for said first and second packet types.

26. The method of claim 22 wherein said selecting step comprises selecting multiplexing options to create different logical channels for said first and second packet types.

27. The method of claim 22 wherein said selecting step comprises selection of a set of encryption keys with an encryption algorithm, from which compressor assigns different encryption keys to said first and second packet types.

28. The method of claim 22 wherein said system is disposed to compress packet headers in accordance with a scheme selected from a group of header compression schemes comprising [VJ], [IPHC], [CRTP], [LLA] and [ROHC].

29. The method of claim 22 wherein said selecting step comprises selecting N different packet transmission characteristics for respectively identifying the packets of N different packet types.

30. The method of claim 22 wherein said second packet type comprises packets which have headers.

31. In a system for transmitting packets over a link between a communicating party and a decompressor, a method of implicit packet type identification comprising the steps of:

selecting a set of implicit packet transmission characteristics, comprising at least first and second distinguishably different transmission characteristics, wherein the first transmission characteristic is associated with a first packet type that is header free and the second transmission characteristic is associated with a second packet type which is different from the first packet type; and

selecting a number of specific packet sizes for use only with header free packets, wherein said communicating party uses one of said specific packet sizes to transmit only header free packets; and

operating said decompressor to detect said transmission characteristics of packets received by said decompressor to thereby identify a received packet as being either the first or second packet type.

32. The method of claim 31 wherein said selecting step comprises a pre-negotiation between said communicating party and said decompressor.

33. The method of claim 31 wherein said selecting step comprises selecting different packet sizes for said first and second packet types.

34. The method of claim 31 wherein said selecting step comprises selecting different sets of channel coding combinations for said first and second packet types.

35. The method of claim 31 wherein said selecting step comprises selecting multiplexing options to create different logical channels for said first and second packet types.

36. The method of claim 31 wherein said selecting step comprises selection of a set of encryption keys with an encryption algorithm, and using different encryption keys for said first and second packet types.

37. The method of claim 31 wherein said system is disposed to decompress packet headers in accordance with a scheme selected from a group of header compression/decompression schemes comprising [VJ], [IPHO], [CRTP],[ELLA]and [ROHC].

38. The method of claim 31 wherein said selecting step comprises selecting N different packet transmission characteristics for respectively identifying the packets of N different packet types.

39. The method of claim 31 wherein said first packet type comprises header free packets. and said second packet type comprises packets which have headers.