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14. Configuration Parameters

Header compression parameters are negotiated in a way specific to the link-layer implementation. Such procedures for link-layer xxx needs to be specified in a document "IP header compression over xxx". Such a document exists for PPP [PPP-HC].

The following parameter is fixed for all implementations of this header compression scheme.

 MIN_WRAP     - minimum time of generation value wrap around

      3 seconds.

The following parameters can be negotiated between the compressor and decompressor. If not negotiated their values must be as specified by DEFAULT.

 F_MAX_PERIOD - Largest number of compressed non-TCP headers that
                may be sent without sending a full header.

      DEFAULT is 256

      F_MAX_PERIOD must be at least 1 and at most 65535.


 F_MAX_TIME   - Compressed headers may not be sent more than
                F_MAX_TIME seconds after sending last full header.

      DEFAULT is 5

      F_MAX_TIME must be at least 1 and at most 255.

      NOTE:  F_MAX_PERIOD and F_MAX_TIME should be lower when it is
             likely that a decompressor loses its state.


 MAX_HEADER   - The largest header size in octets that may
                be compressed.

      DEFAULT is 168 octets, which covers

                      - Two IPv6 base headers
                      - A Keyed MD5 Authentication Header
                      - A maximum-sized TCP header

      MAX_HEADER must be at least 60 octets and
              at most 65535 octets.


 TCP_SPACE    - Maximum CID value for TCP.

      DEFAULT is 15   (which gives 16 CID values)

      TCP_SPACE must be at least 3 and at most 255.


 NON_TCP_SPACE    - Maximum CID value for non-TCP.

      DEFAULT is 15   (which gives 16 CID values)

      NON_TCP_SPACE must be at least 3 and at most 65535.


 EXPECT_REORDERING       - The mechanisms in section 11 are used.

      DEFAULT no.