Comment 9 for bug 761955

Klaus Warnke (k-warnke) wrote :

The IP-ID is stored complete in the 16bit in extension 3.
Crystal clear (haha) from rfc3095 4.5.7:

4.5.7. Encoded values across several fields in compressed headers

   When a compressed header has an extension, pieces of an encoded value
   can be present in more than one field. When an encoded value is
   split over several fields in this manner, the more significant bits
   of the value are closer to the beginning of the header. If the
   number of bits available in compressed header fields exceeds the
   number of bits in the value, the most significant field is padded
   with zeroes in its most significant bits.

The IP-ID needs only 16bit, therefore the upper 5bits are padded with zero,
if the compressed IP-ID needs more than 5bits to transmit. If 5bit are sufficient,
it should be stored in the base header.

http://www.ietf.org/mail-archive/web/rohc/current/msg01677.html

Therefore my correction is incomplete, because the 5bit in base header
should be padded with zero at compressor.

regards, Klaus