[ee122] HW Question 2, part C

Vern Paxson vern at icir.org
Sun Sep 30 10:57:57 PDT 2007

> Quick question. The RFC that is mentioned in this question is obsolete,
> right?

No, it's the standard that defines IP.  There have been some updates to
it, but nothing major.

> I looked up a diagram for IPv4, and the length of the "Options"
> section was longer on that diagram than on the RFC.

In the diagram, Options refers to the *entire* space available for all of
the options present in an IP header.  The part of RFC 791 to which the
problem refers you discusses the layout of a *single* option that can be
specified in that space.  As the RFC indicates, that option can itself
have a variable length.


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