*MULTIPLE* subnets down a SINGLE connection

John-David Childs (jdc@ism.net)
Wed, 6 Nov 1996 05:27:20 -0700 (MST)

On an LOCAL IRX-111, I have set up three frame-relay PVC's so far...for the
sake of argument assume all remote networks have subnet .248 (30-hosts).
All of these sites are remote POPs with one subnet going to the Ethernet
interface so that office/school machines may connect to the PM's ethernet
port, and another subnet is used by the modem bank (PM2ER-30).

Now, one of these remote locations needs an *additional* 30 IP addresses
routed to the Ethernet interface! Because I anticipated this, I had left a
contiguous subnet to the one he's using open (Had I *REALLY* known that
they were definately going to use the additional 30 IP's I would have put
them on a .192 subnet, but that's a different story). I *thought* that
even though the PM's don't do VLSM that I would be able to route this
second subnet to it via static routing. In fact, a traceroute of an IP
address in the second subnet DOES get to the remote PM, but the customer is
unable to see it or get any machines in the second subnet to see the PM
(who's ethernet address is in the first subnet). Is there anything I can
do to get the second subnet recognized by computers on the remote PM's
ethernet port???

GORY DETAILS:

On the IRX (local):
add netmask XXX.YYY.ZZZ.0 255.255.255.248
route add XXX.YYY.ZZZ.64 XXX.YYY.WWW.2 1 (ethernet subnet...this works)
route add XXX.YYY.ZZZ.32 XXX.YYY.WWW.2 1 (modem subnet..also works)

route add XXX.YYY.ZZZ.96 XXX.YYY.WWW.2 1 (SECOND SUBNET of 30 IP's)
Traceroutes to XXX.YYY.ZZZ.97-126 DO make it to XXX.YYY.WWW.2!!

I have also tried
route add XXX.YYY.ZZZ.96 XXX.YYY.ZZZ.65 (the IP address of the remote PM
ethernet interface)

I entered the same netmask table and routing commands on the remote PM as
shown above...no dice. I cannot ping/traceroute to any IP on the second
subnet. Do I have to renumber the original 30 IP's to a .192 network???
Just say NO! :-) Is this an error in PC configuration or a limitation
of RIPv1??

--

John-David Childs www.marsweb.com/www.ism.net System Administrator Internet Services Montana (406)721-6277 & Network Engineer M@RSWeb - Montana's PREMIER Web Site "I used up all my sick days...so I'm calling in dead"