[e2e] Header length field in IP header

[Saad Biaz]

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-

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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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