RE: [nsp] OSPF quickie

From: Martin, Christian (cmartin@gnilink.net)
Date: Wed Mar 28 2001 - 10:19:05 EST


Neil,

The default is(was) 6, now may be 8 or 16 even...

If I understand this correctly, the 3 subnets are closer to A than they are
to B, and hence, A has a shorter distance to the subnets. B has a higher
cost. The only thing that will have equal cost in your diagram from C is
the route to the T3 between A& B, assuming the cost is the same on both
sides.

Can you send a snippet of the database entries and a show ip ospf interface
for all three interfaces? Whwre do the subnets live relative to A & B?

thanks,
chris

> -----Original Message-----
> From: Neil J. McRae [mailto:neil@COLT.NET]
> Sent: Wednesday, March 28, 2001 3:17 AM
> To: Charles Sprickman; Martin, Christian
> Cc: cisco-nsp@puck.nether.net
> Subject: RE: [nsp] OSPF quickie
>
>
> Try adding
>
> router ospf x
> maximum-paths 2
>
> Regards,
> Neil.
>
> > -----Original Message-----
> > From: Charles Sprickman [mailto:spork@inch.com]
> > Sent: 28 March 2001 08:15
> > To: Martin, Christian
> > Cc: cisco-nsp@puck.nether.net
> > Subject: RE: [nsp] OSPF quickie
> >
> >
> >
> > On Tue, 27 Mar 2001, Martin, Christian wrote:
> >
> > > Chales,
> > >
> > > Can you draw this out? Which side cannot see the other? Is
> > the new split
> > > side connected to a LAN? Is there a DR election happening here?
> >
> > 2xT1
> > -------- router A
> > router C
> > 2xT1
> > -------- router B
> >
> > I simply moved "C" from "A" to "B" (no ip changes). A and B have
> > identical configs for ospf and the two serial interfaces.
> A and B are
> > connected via a T3 and speak OSPF. There were no changes
> made to C. C
> > sees routes via both T1's. B only sees routes via one T1.
> >
> > 'show ip ospf neigh detail' verifies that both links are up
> and exchanging
> > routes. Here's the brief output:
> >
> > C:
> > Inch-Whitehall-gw>show ip ospf neighbor
> >
> > Neighbor ID Pri State Dead Time Address
> > Interface
> > 192.168.210.1 1 FULL/ - 00:00:36
> 192.168.200.205 Serial0/0
> > 192.168.210.1 1 FULL/ - 00:00:36
> 192.168.200.201 Serial0/1
> >
> > (here's a route learned from B)
> > Inch-Whitehall-gw>show ip route 192.168.198.0
> > Routing entry for 192.168.198.0/24, 2 known subnets
> > [...]
> > O E2 192.168.198.0/26 [110/20] via 192.168.200.201,
> 1d11h, Serial0/1
> > [110/20] via 192.168.200.205,
> 1d11h, Serial0/0
> >
> > B:
> >
> > core-2>sh ip ospf neighbor
> >
> > Neighbor ID Pri State Dead Time Address
> > Interface
> > 192.168.210.4 1 FULL/ - 00:00:32
> 192.168.200.202 Serial2/0
> > 192.168.213.1 1 FULL/ - 00:00:39
> 192.168.200.65 Serial4/0
> > 192.168.210.4 1 FULL/ - 00:00:33 192.168.200.206
> > Serial5/0/1:0
> > (2/0 and 5/0/1 are the two T1's)
> >
> > (here's a route learned from C - only one path)
> > core-2>show ip route 192.168.192.0
> > Routing entry for 192.168.192.0/24, 4 known subnets
> > Variably subnetted with 4 masks
> > Redistributing via ospf 1
> >
> > O E2 192.168.192.128/30 [110/20] via 192.168.200.202,
> 1d11h, Serial2/0
> > O E2 192.168.192.64/27 [110/20] via 192.168.200.202,
> 1d11h, Serial2/0
> > O E2 192.168.192.96/28 [110/20] via 192.168.200.202,
> 1d11h, Serial2/0
> >
> > Any ideas? Sorry for all the clutter, I was hoping that
> putting all this
> > info together would help me see the problem...
> >
> > Thanks,
> >
> > Charles
> >
> > > chris
> > >
> > > > -----Original Message-----
> > > > From: Charles Sprickman [mailto:spork@inch.com]
> > > > Sent: Tuesday, March 27, 2001 11:52 AM
> > > > To: cisco-nsp@puck.nether.net
> > > > Subject: [nsp] OSPF quickie
> > > >
> > > >
> > > > Hi,
> > > >
> > > > Small OSPF problem that's got me scratching my head...
> I just moved a
> > > > connection from one router to another (two T1's). Both
> the previous
> > > > router these went back to and the new one are in the same
> > > > ospf area, and
> > > > I've verified that all the neighbors see each other.
> > > >
> > > > On the old router, I was seeing routes from the remote side
> > > > via both T1
> > > > connections, which gave me a sort of load-balancing between
> > > > the two lines.
> > > > On the new router, even though I see the remote side listed
> > > > as a neighbor
> > > > twice, I only see routes via one T1.
> > > >
> > > > OSPF config is identical on both routers, is there a
> global switch I'm
> > > > missing somewhere? I know this is something silly and
> > > > obvious, but I'm
> > > > not seeing it... Old router is running 12.0.7T, new is
> 12.0.7XE1.
> > > >
> > > > Thanks,
> > > >
> > > > Charles
> > > >
> > > > | Charles Sprickman | Internet Channel
> > > > | INCH System Administration Team | (212)243-5200
> > > > | spork@inch.com | access@inch.com
> > > >
> > >
> >
> >
> >
> >
>



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