FILLMORE@EMRCAN.BITNET (06/06/90)
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) 996-2953adelman@TGV.COM (Kenneth Adelman) (06/07/90)
> 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. Our MultiNet TCP/IP product for VMS can do this; it isn't documented but customer service can give you the instructions for enabling it. We don't want to encourage people to run multiple network numbers on the same cable because of the potential for problems with broadcasts. Basically we allow you to create two `interfaces' for one ethernet controller. Each has its own address, and you can gateway between them, run routing protocols, etc, just as if you had multiple controllers on separate cables. This would allow you to do with (1) and (2) above. If you have any other questions, give me mail or a call at 800-TGV-3440 or 408-427-4366. If you'd like to try it, we have an evaluation/trade-in program so I can get a copy right out to you. Kenneth Adelman TGV, Inc.
kwe@bu-it.bu.edu (Kent England) (06/12/90)
In article <90Jun6.101602edt.57781@ugw.utcs.utoronto.ca>, FILLMORE@EMRCAN.BITNET writes: > ... 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. Multiple subnets on a single interface is a feature of the latest cisco software. Look in the manual update section, not the manual. It is the primary/secondary designation of the ip-address of a given interface. ... > 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? > Rather than configure each host to be a member of each subnet on the given wire, I would recommend setting the subnet mask such that each host on the wire would ARP for all directly connected hosts. You could simply set the subnetmask to the netmask (ie, no subnet) on each host on the LAN and let the router proxy for any nonlocal destinations. This seems to me to be a cleaner approach than creating multiple addresses for each host on the shared subnets. This will not work for multiple networks, only subnets.