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[ih] IPv4 address size debate

> Ah yes, Ethernet hacking sounds like a BSD project.  I may also be
> confusing the TCP and IP checksumming - it's been a long time.  There
> was some reason for considering trailers though.  Can't remember..

The other reason for considering trailers was that you could put the
checksum at the end, which was nice for sending (you could append
the checksum on the way out).  There's no win on receiving end unless you
split the header into a fixed-size leader that aligns the data and tells you
where the data is going and a trailer that has the variable parts of the
header (checksum can go either place with equal benefit/pain for the receiver).
There's also no win for the router unless all routable info is in the leader.

Speaking, of course, c. 1980 platforms.  Today's mileage would vary (though
less than some notes imagine).