Path: utzoo!attcan!uunet!samsung!usc!ucsd!ucbvax!EMRCAN.BITNET!FILLMORE
From: FILLMORE@EMRCAN.BITNET
Newsgroups: comp.protocols.tcp-ip
Subject: Multiple IP networks on one Ethernet interface
Message-ID: <90Jun6.101602edt.57781@ugw.utcs.utoronto.ca>
Date: 6 Jun 90 15:12:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 32

I have a (perhaps) naive question for the TCP/IP gurus:

I know that the general philosophy in interconnecting IP networks is to use
a router with two interfaces.  I would like a cheaper solution and was wondering
if anyone has got this to work in practice:

We have several organizations with TCP/IP networks, and we have a class B
network number that we divided up into subnetworks (23 bit mask) and allocate
subnetworks to the organizations.  Now the organizations want to talk to each
other.  They are all on Ethernet networks.  I would like to know if any of
the commercially-available TCP/IP packages have the capability of either:

     1)  sending and receiving IP packets for more than one subnetwork
         over the same Ethernet interface.

 or: 2)  routing packets between two or more subnetworks over the
         same Ethernet interface.

We have several spare Ethernet bridges but only one router - a Cisco.
The Cisco documentation implies that each Ethernet interface can be
configured with more than one IP network address but I haven't actually
tried it.  Does this feature have any limitations?
We also run WIN/TCP for VAX/VMS and Control Data's TCP/IP product.  Can
either of these be configured for multiple subnets on one interface?

Thanks for any insight you can provide.

________________________
Bob Fillmore, Systems Software & Communications     BITNET:  FILLMORE@EMRCAN
  Computer Services Centre,                         BIX:     bfillmore
  Energy, Mines, & Resources Canada                 Voice:   (613) 992-2832
  588 Booth St., Ottawa, Ontario, Canada  K1A 0E4   FAX:     (613) 996-2953