Method and apparatus for handling out-of-sequence packets in header decompression

A method of operating a remote terminal which receives, over a link, packets including packets having headers which have been compressed and packets which are potentially out-of-order, the method comprising:

• (1) detecting possible context damage attributable to missing or out-of-order packets in a flow of packets over the link;
• and thereafter:
• (2) storing packets which initially fail header decompression;
• and then,
• (3) successfully using certain context information to perform header decompression of a packet received after detection of the context damage;
• and
• (4) reattempting header decompression of the stored packets using the certain context information;
• wherein the certain context information comprises a semi-static field of state information obtained from a successfully header decompressed packet and which is necessary for header decompression of a packet that initially fails header decompression, the certain context information being configured to update context fields including context fields other than a serial number field or a time stamp field.

A header decompressor for use in a remote terminal which receives, over a link, packets including packets having headers which have been compressed and packets which are potentially out-of-order, the header decompressor being configured to perform the acts of:

• (1) detecting possible context damage attributable to missing or out-of-order packets in a flow of packets over the link;
• and thereafter:
• (2) storing packets which initially fail header decompression;
• and then,
• (3) successfully using certain context information to perform header decompression of a packet received after detection of the context damage;
• and
• (4) reattempting header decompression of the stored packets using the certain context information;
• and
• wherein the certain context information comprises a semi-static field of state information obtained from a successfully header decompressed packet and which is necessary for header decompression of a packet that initially fails header decompression, the certain context information being configured to update context fields including context fields other than a serial number field or a time stamp field.

A method of operating a telecommunications network comprising:

• sending from the network to a remote terminal, over an interface, packets including packets having headers which have been compressed, and packets which are potentially out-of-order;
• detecting a situation in which packets sent from the network to the remote terminal have a likelihood of being out-of-order;
• and in response thereto performing a repair process comprising:
• temporarily allocating memory locations for storing a set of context information existing at times at which packet loss at least appears to occur by packets possibly being out-of-order, and de-allocating the memory locations so that the memory location are utilized for other usages when the repair process is not invoked, the context information having been obtained from successfully decompressed packets;
• using the set of context information to reattempt header decompression of subsequently received packets that previously failed header decompression possibly by being out-of-order;
• and
• wherein the context information used to reattempt the header decompression is configured to update context fields including context fields other than a serial number field or a time stamp field.