Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!pasteur!ucbvax!MONK.PROTEON.COM!jas
From: jas@MONK.PROTEON.COM ("John A. Shriver")
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Internet subnet addressing
Message-ID: <8803181844.AA15430@monk.proteon.com>
Date: 18 Mar 88 18:44:35 GMT
References: <8803181033.aa13032@Louie.UDEL.EDU>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 12

There is no restriction with having one Ethernet be two, three or even
four subnets.  The cost will be that machines on different subnets of
the Ethernet will have to use a router to communicate.

One trcik can be played to work around this: assign the ethernet
subnets so that they only differ in the lowest bit(s) of the subnet
portion of the address.  You tell the gateways the true number of
subnet bits, but lie to the hosts and tell them there are one (or
more) less subnet bits.  They then can communicate between the subnets
without using routers.

All the routers MUST agree on the number of subnet bits used on a
given network.