[e2e] Header length field in IP header

Craig Partridge craig at aland.bbn.com
Thu Sep 23 10:22:20 PDT 2004

In message <4152F8A9.2090500 at isi.edu>, Joe Touch writes:

>Error - drop the packet. If the IP version field is 4 (I'm assuming you 
>mean IPv4), there are required fixed-length fields. As per RFC791, pg 11:


You're quite right, but realize the point here -- we have found some
free bits!!

All we need to do is write a standards document that says values
0,1,2,3 and 4 are to be interpreted as "5 + a bit value to be determined"
and we get 5 more values we can signal in the IP header!  Diff serv
has more bits to play with!  <Running for cover... :-)>


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