[unisog] Server based scan for student computers

Valdis.Kletnieks at vt.edu Valdis.Kletnieks at vt.edu
Tue May 17 20:16:18 GMT 2005


On Tue, 17 May 2005 14:06:28 EDT, Oscar Knight said:

> At least one commercial application uses (or did in the past) 30 bit
> networks.  You would need a large address space.  If you needed some
> external access, ie windows update then I think you would do NAT.
> 

>      10.100.16.0     broadcast
>      10.100.16.1     workstation
>      10.100.16.2     router
>      10.100.16.3     network mask

At least one person realized that this is wasteful, because there's only 2
possible boxes on the wire, so "broadcast" and "mask" don't matter - there's
only "this end" and "other end".  So you only need one bit, and a 31 bit network.

3021 Using 31-Bit Prefixes on IPv4 Point-to-Point Links. A. Retana, R.
     White, V. Fuller, D. McPherson. December 2000. (Format: TXT=19771
     bytes) (Status: PROPOSED STANDARD)
http://www.ietf.org/rfc/rfc3021.txt

There's a *lot* of use of this for point-to-point links - if you have a router
that's got an OC-3 coming in one side, and a whole mess of fractional T-1 coming
out the other, you burn only half as many IP addresses. (And that's a fairly
common configuration for many ISPs that sell leased-line connectivity).
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