1. A method for header compression between a compressor and a decompressor, the method comprising:
providing a set of configuration parameters to be negotiated between the compressor and the decompressor, wherein said set comprises a specific parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
2. The method according to claim 1, wherein the method comprises:
indicating in a full header whether a subsequent compressed header will contain a packet sequence number.
3. The method according to claim 2, wherein the method comprises:
indicating in the full header whether the subsequent compressed header will contain the packet sequence number in a situation in which said specific parameter has been negotiated to the value which indicates that reordering andor packet loss is tolerated.
4. The method according to claim 2, wherein the full header comprises a specific header field whose specific first value indicates that the subsequent compressed header will not contain the packet sequence number and whose value other than the first value indicates that the subsequent compressed header will contain the packet sequence number.
5. The method according to claim 4, wherein said specific first value is the value zero and said value other than the first value is a non-zero value.
6. The method according to claim 5, wherein said non-zero value is the first packet sequence number or comprises bits of the first packet sequence number, such as a number of least significant bits of the first packet sequence number.
7. The method according to claim 2, wherein the full header is sent from the compressor to the decompressor during an initialization phase of a session.
8. The method according to claim 2, wherein said specific field used for indicating whether a subsequent compressed header will contain a packet sequence number is a length field, such as an IP length field.
9. The method according to claim 2, wherein the compressed header comprises a compressed TCP header, such as a header of the type COMPRESSED_TCP.
10. The method according to claim 1, wherein the method comprises:
taking the mode of a lower protocol layer, such as LLC (Logical Link Control) acknowledgementunacknowledgement mode, into account when negotiating the value of the specific parameter whose value indicates whether reordering andor packet loss is tolerated.
11. The method according to claim 1, wherein the specific parameter whose value indicates whether reordering andor packet loss is tolerated is the parameter EXPECT_REORDERING.
12. The method according to claim 1, wherein the compressor and the decompressor are SNDCP (Subnetwork Dependent Convergence Protocol) entities.
13. The method according to claim 1, wherein the negotiation is the SNDCP XID negotiation.
14. A transmitting device comprising a compressor for header compression between the compressor and a decompressor, said transmitting device comprising:
means for providing a set of configuration parameters to be negotiated between the compressor and the decompressor, wherein said set comprises a parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
15. The transmitting device according to claim 14, wherein the transmitting device comprises:
means for indicating in a full header whether a subsequent compressed header will contain a packet sequence number.
16. The transmitting device according to claim 15, wherein the full header comprises a specific header field whose specific first value indicates that the subsequent compressed header will not contain the packet sequence number and whose value other than the first value indicates that the subsequent compressed header will contain the packet sequence number.
17. The transmitting device according to claim 16, wherein said specific first value is the value zero and said value other than the first value is a non-zero value.
18. The transmitting device according to claim 17, wherein said non-zero value is the first packet sequence number or comprises bits of the first packet sequence number, such as a number of least significant bits of the first packet sequence number.
19. The transmitting device according to claim 15, wherein said specific field used for indicating whether a subsequent compressed header will contain a packet sequence number is a length field, such as an IP length field.
20. The transmitting device according to claim 14, wherein the transmitting device comprises:
means for taking the mode of a lower protocol layer, such as LLC (Logical Link Control) acknowledgementunacknowledgement mode, into account when negotiating the value of the specific parameter whose value indicates whether reordering andor packet loss is tolerated.
21. The transmitting device according to claim 14, wherein the transmitting device is selected from the group comprising: a terminal device of a communications network, such as a wireless terminal device of a mobile communications network, and a network element of a communications system, such as a support node of a mobile communications system.
22. A receiving device comprising a decompressor for decompression of compressed headers received from a compressor, said receiving device comprising:
means for negotiating a set of configuration parameters between the decompressor and the compressor, wherein said set comprises a parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
23. The receiving device according to claim 22, wherein the receiving device comprises:
means for receiving an indication in a full header whether a subsequent compressed header will contain a packet sequence number.
24. The receiving device according to claim 23, wherein the full header comprises a specific header field whose specific first value indicates that the subsequent compressed header will not contain the packet sequence number and whose value other than the first value indicates that the subsequent compressed header will contain the packet sequence number.
25. The receiving device according to claim 24, wherein said specific first value is the value zero and said value other than the first value is a non-zero value.
26. The receiving device according to claim 25, wherein said non-zero value is the first packet sequence number or comprises bits of the first packet sequence number, such as a number of least significant bits of the first packet sequence number.
27. The receiving device according to claim 23, wherein said specific field used for indicating whether a subsequent compressed header will contain a packet sequence number is a length field, such as an IP length field.
28. The receiving device according to claim 22, wherein the receiving device comprises:
means for taking the mode of a lower protocol layer, such as LLC (Logical Link Control) acknowledgementunacknowledgement mode, into account when negotiating the value of the specific parameter whose value indicates whether reordering andor packet loss is tolerated.
29. The receiving device according to claim 22, wherein the receiving device is selected from the group comprising: a terminal device of a communications network, such as a wireless terminal device of a mobile communications network, and a network element of a communications system, such as a support node of a mobile communications system.
30. A system comprising a compressor and a decompressor for header compression between the compressor and the decompressor, the system comprising:
means for providing a set of configuration parameters to be negotiated between the compressor and the decompressor, wherein said set comprises a parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
31. A software application executable in a transmitting device, the software application comprising:
program code for implementing a compressor for header compression between the compressor and a decompressor; and
program code for providing a set of configuration parameters to be negotiated between the compressor and the decompressor, wherein said set comprises a parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
32. A software application executable in a receiving device, the software application comprising:
program code for implementing a decompressor for decompression of compressed headers received from a compressor; and
program code for negotiating a set of configuration parameters between the decompressor and the compressor, wherein said set comprises a parameter whose value indicates whether reordering andor packet loss is tolerated between the compressor and the decompressor.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. (canceled)
2. A digital camera having a movable mirror provided so as to enter or retract with respect to an optical path of an image pickup optical system for purpose of guiding a subject image to an optical viewfinder, comprising:
an image pickup element that captures the subject image formed by the image pickup optical system to generate image data;
a battery cover that openscloses a battery accommodating portion accommodating a battery;
a display portion that displays the image data generated by the image pickup element or image data obtained by subjecting the image data generated by the image pickup element to predetermined processing; and
a control portion having a live view mode controlling so that the image data generated by the image pickup element or the image data obtained by subjecting the image data generated by the image pickup element to predetermined processing is displayed on the display portion as a moving image in real time,
wherein when the battery cover is opened when the live view mode is set, the control portion controls so that the digital camera comes out of the live view mode, and the movable mirror enters the optical path of the image pickup optical system.
3. A digital camera to which an interchangeable lens included in an image pickup optical system is attachabledetachable, having a movable mirror provided so as to enter or retract with respect to an optical path of an image pickup optical system for purpose of guiding a subject image to an optical viewfinder, comprising:
an image pickup element that captures the subject image formed by the image pickup optical system to generate image data;
a display portion that displays the image data generated by the image pickup element or image data obtained by subjecting the image data generated by the image pickup element to predetermined processing; and
a control portion having a live view mode controlling so that the image data generated by the image pickup element or the image data obtained by subjecting the image data generated by the image pickup element to predetermined processing is displayed on the display portion as a moving image in real time,
wherein when the attached interchangeable lens is removed when the live view mode is set, the control portion controls so that the digital camera comes out of the live view mode, and the movable mirror enters the optical path of the image pickup optical system.