[e2e] Header length field in IP header

[Joe Touch]

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:

>   IHL:  4 bits
> 
>     Internet Header Length is the length of the internet header in 32
>     bit words, and thus points to the beginning of the data.  Note that
>     the minimum value for a correct header is 5.

I.e., this would mean an "incorrect header".

Joe

Saad Biaz wrote:

> The header length HL of IP header has 4 bits.
> Normally, the header length HL would be a number from 5 (no options) to
> 15. Since the IP header is at least 5, I wonder if the field HL can take
> the values 0, 1, 2, 3, or 4 to mean something else. If it takes such values
> (0-4), what is the meaning?
> 
> Thank you-
> 
> ----------------------------------------------------------------------
> Saad Biaz, Ph.D., Assistant Prof.     Voice: (334) 844 6307
> 114 Dunstan Hall Auburn University    Fax  : (334) 844 6329
> Auburn, AL 36849-5347, USA            http://www.eng.auburn.edu/~sbiaz
> ----------------------------------------------------------------------
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