The Packet by Packet context is cleared between Packets so that this History Buffer is not maintained across Packet boundaries. To ensure that Packets are being compressed and decompressed correctly and to ensure History Buffer synchronization is maintained, a Packet Integrity Byte is added to the packet header. The packet integrity byte is defined in the full protocol specification. By default or ultimate disagreement, no compression is used. Type 24 Length 4 FE - Features Negotiates features specific to this compression algorithm.
History Defines the size of the compression history buffer.
Valid values are defined in the full protocol specification. This is the number of contexts. Each context implies the creation of a History Buffer for that context of the size indicated in the Context History field. Values are 1-63. This value includes both the Packet by Packet context and the number of contexts for which history is maintained.