Header Compression Lost Full Header Recovery
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Solution Overview
Problem
Existing header compression techniques, such as RFC 2507, face inefficiencies in recovering lost full headers, particularly in wireless mobile environments, where the packet containing the full header can be lost, leading to undecodable messages and suboptimal compression due to reliance on refresh mechanisms that are either too frequent or too infrequent.
Innovation Solution
A method for efficiently recovering a lost full header during header compression involves sending a first full header with context identification and generation identification, incrementing the generation identification upon detection of loss, and actively requesting a full header refresh to ensure timely recovery without waiting for predefined packet counts or time thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If header compression is used to reduce overhead, then packet size and bandwidth consumption are reduced, but reliability deteriorates because lost full headers cause undecodable compressed packets
Solution Approach 1:
The patent applies preliminary action by proactively sending full headers at predefined intervals and upon detecting context changes, rather than waiting for compression failures. The source proactively transmits full headers to establish context at the destination before compressed headers are sent, ensuring the destination has the necessary context information ready to decode compressed packets even if transmission conditions deteriorate
Solution Approach 2:
The patent implements feedback mechanisms where the destination monitors received packets for context changes and sends notifications back to the source when context updates are needed. This feedback loop ensures that full headers are retransmitted or updated at the source based on actual destination needs, maintaining reliability while minimizing unnecessary overhead
2Productivity
If full header refresh intervals are increased to reduce overhead, then compression efficiency improves, but header loss probability increases leading to more undecodable packets
Solution Approach 1:
The patent applies dynamics by making the full header transmission interval adaptive rather than fixed. The system dynamically adjusts the refresh interval based on observed network conditions, packet loss patterns, and context change frequencies. When loss is detected or context changes occur, the system shortens the interval to send full headers more frequently, thereby maintaining reliability while preserving compression efficiency during stable periods
Solution Approach 2:
The patent changes the parameter of header refresh timing from a static predefined interval to a dynamic parameter that adjusts based on network conditions. By monitoring packet acknowledgments and context stability, the system modifies the refresh interval parameter in real-time, extending intervals during stable conditions to maximize compression while reducing intervals when loss is detected to maintain reliability
3Reliability
If full headers are sent frequently to ensure recovery, then reliability improves, but compression benefits are reduced due to increased overhead
Solution Approach 1:
The patent applies partial action by sending full headers only when necessary - specifically at context change points and when loss is detected - rather than sending them continuously or at fixed frequent intervals. This selective approach provides sufficient header information for reliable recovery while minimizing the overhead associated with frequent full header transmissions, thereby maintaining compression benefits
Data Source
AI summary
A method is disclosed that includes sending (304) a first full header from a source compressor (106) to a destination decompressor (112) wherein the source compressor and the destination decompressor are a part of a symmetrical configuration. An IP packet including the full header is compressed into a first compressed header (310) based on the context established in the first full header. The first compressed header is sent (312) from the source compressor to the destination decompressor. The compressor receives (322) a second full header from the destination compressor wherein the second full header indicates that the destination decompressor did not receive the first full header. The second full header can include a modified field or has an incremented generation identification. The source compressor sends (336) another full header to the destination decompressor.