Re: [nsp] OSPF quickie

From: Charles Sprickman (spork@inch.com)
Date: Wed Mar 28 2001 - 17:46:53 EST


Hi,

Thanks to everyone for their replies. The problem is that the quad serial
interface defaulted to a metric of 48, while a full T1 on the CT3 is
weighted to 65. Changing it to 48 made everything happy.

Faraz said it's fractional, but it's not... Both are full T's. Any idea
why the defaults would differ?

Thanks,

Charles

| Charles Sprickman | Internet Channel
| INCH System Administration Team | (212)243-5200
| spork@inch.com | access@inch.com

On Wed, 28 Mar 2001, Faraz Shamim wrote:

> Charles,
>
> If you look at the show ip ospf nei output on router B:
>
> > 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
> ^^^^^^^^^^^^^^
>
> This Serial5/0/1:0 is a fractional T1 and if you do show int for this
> you will see a bandwidth value of 64K where as Serial 2/0 would show
> you the bandwidth as 1544K. Obviously route B would prefer all routes
> via serial2/0.
>
> Faraz Shamim
> sshamim@cisco.com
>
>
>
> >
> >
> > 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
> > > >
> > >
> >
> >
> >
>



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:33 EDT