Right off the top I wanted to say "NO! - you can't do this..." but then I
saw that we were talking about serials here so I did a test. Sure enough I
was able to put two serial interfaces on the same router into the same
subnet. Didn't think that was possible. However, as I suspected - as soon
as I tried to put an Ethernet interface into any subnet in use by any other
interface - I got the error that it "overlaps" with interface x.
So now we know that Yes you can do it - but will it work.
first - we'll assume that the 192.1.67.202/14 is a typo and it should be
192.1.67.202/24
second - let's get rid of the /24 on the transit links
RouterA S0 - 192.1.67.1/30 RouterB S0 - 192.1.67.2/30
RouterA S1 - 192.1.67.5/30 RouterB S1 - 192.1.67.6/30
third - RIP won't like that so change it to version 2
router RIP
version 2
(on both routers of course)
or better yet - use EIGRP.
But - you didn't give us any info about where you pinged from, the router?
a client on the ethernet segment? - what ip address is/are the ethernet
segments? and what was the destination of the ping??? How is RIP
configured?
The more I look at it, it seems like a strange network - is he maybe
bridging and not routing?
That the network is slow isn't too hard to figure. With two interfaces in
the same subnet the router has to try and figure out - here's a packet - I
can ship it to:
1. S0
2. S1
3. Nowhere - I don't have to!! we're all on the same network!!
4. All of the above
5. None of the above
6. 1 and 2
With only one serial up, the choices become easier.
And are we talking about redundant, x amount of bandwidth required but a
backup connection?
Or two circuits load balancing, or a combination?
Too many variables not presented, need more info - perhaps configs??? (and
design objectives?)
Kevin Wigle
----- Original Message -----
From: "Dimitrije" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, 25 March, 2001 13:13
Subject: redundant serial links in same subnet??
> I colleague of mine has a network connecting two routers with redundant
serial
> links. These serial links happen to reside in the same subnet as follows:
>
> Router
> A
Router
> B
> S0 - 192.1.67.1/24 ----------------------------- 192.1.67.201/24 - S0
> S1 - 192.1.67.2/24 ----------------------------- 192.1.67.202/14 - S1
>
> Both Routers are running RIP.
>
> When both links are up, network is very sluggish and ping works
intermittently
> (anywhere from 40%-70% of the time) between Routers A & B. When either
link is
> shut down (only one link is up at a time), pings work 100% of the time.
>
> I'm suspecting that having both serial links in the same subnet is
creating
> problems. First of all, can you even do this? Secondly, if you can put
both
> serial 0 & 1 in the same subnet, is this creating a layer-2 bridge-loop
> environment?
>
> I think that putting each serial link in a separate sub-net should solve
the
> problem, but I don't have access to any equipment to test this.
>
> Am I correct or off-base?? Any definitive feedback would be great. Any
links
> to spell out the issues with this scenario would also be helpful.
>
> thanks,
> dj
>
>
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