[ih] "Subnet"

[Larry Sheldon]

I have no useful credentials for any of the current discussion, but I do 
have a question about the term "subnet" as has been used a couple of times.

The word interests me because I was at battle with people for their use 
in the classless IP world (I was an administrator at a small school here).

People with forever talk as if the subnet number was the third octet in 
the dotted decimal representation of the IP address, and that decisions 
could be made using that at the originating end or anywhere in the 
middle.  I argued and still do that it is mostly a useless datum and can 
not be known anywhere except on the leg between the destination station 
ant the router talking to it.

In the ARPANet discussion, what does "subnet" refer to?  It seems like 
there must have been a bigger network that I don't know anything about.
-- 
Requiescas in pace o email           Two identifying characteristics
                                         of System Administrators:
Ex turpi causa non oritur actio      Infallibility, and the ability to
                                         learn from their mistakes.
ICBM Data:  http://g.co/maps/e5gmy        (Adapted from Stephen Pinker)