From: Wu, Jiang (wujiang@xxxxxxxxx)
Date: Mon Dec 04 2000 - 08:19:08 GMT-3
Simon,
Sounds like you did not break the initial connection between area 0 and area 2.
And you got a somewhat strange topology. Just a thought.
Wu
----- Original Message -----
From: Simon Baxter <Simon.Baxter@au.logical.com>
To: Brian Hescock <bhescock@cisco.com>; Simon Baxter <Simon.Baxter@au.logical.c
om>
Cc: CCIE Group Study (E-mail) <ccielab@groupstudy.com>
Sent: Monday, December 04, 2000 12:30 PM
Subject: RE: OSPF Virtual links stuff up routing...
> This I don't understand.
>
> I understand that intra are preferred over inter-area, but as I illustrated,
> the only thing I changed was to make area1 a transit area for a VL to area
> 2. Why would the 10.0.x.x network, being in area0, now become INTRA-area??
>
>
> Yikes....
>
> 1 week to go!
>
> -----Original Message-----
> From: Brian Hescock [mailto:bhescock@cisco.com]
> Sent: Monday, December 04, 2000 2:30 PM
> To: Simon Baxter
> Cc: CCIE Group Study (E-mail)
> Subject: Re: OSPF Virtual links stuff up routing...
>
>
> Simon,
> Notice that one is an inter-area route (IA) and the other is an
> intra-area route (O). OSPF is preferring the intra-area route as it
> should.
>
> Brian
>
> On Mon, 4 Dec 2000, Simon Baxter wrote:
>
> > I've discovered Virtual Links seem to prefer a path through some networks
> -
> > against the metric of transiting links....
> >
> > In the below example, a slow speed 64k serial link is preferred over a
> 10Meg
> > connection - because of the Virtual link.....
> >
> >
> > Scenario is - "BOTTOM" is in area 1 and has 2 connections to area 0: via
> > s0/0(toR5) and via e0/0(via R2)
> >
> > Without any VLs configured, the preferred path to area 0 is via the
> > ethernet...
> >
> > (10.0.10.3 is another device in area 0)
> >
> > BOTTOM#sh ip ro
> > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
> > area
> > * - candidate default, U - per-user static route, o - ODR
> > P - periodic downloaded static route
> >
> > Gateway of last resort is not set
> >
> > 192.192.192.0/32 is subnetted, 1 subnets
> > O IA 192.192.192.192 [110/21] via 10.1.2.1, 00:05:15, Ethernet0/0
> > 10.0.0.0/24 is subnetted, 4 subnets
> > O IA 10.0.10.0 [110/20] via 10.1.2.1, 00:05:15, Ethernet0/0
> > O IA 10.3.0.0 [110/68] via 10.1.2.1, 00:05:15, Ethernet0/0
> > C 10.1.2.0 is directly connected, Ethernet0/0
> > C 10.1.1.0 is directly connected, Serial0/0
> > BOTTOM#trace 10.0.10.3
> > Type escape sequence to abort.
> > Tracing the route to 10.0.10.3
> >
> > 1 10.1.2.1 0 msec 0 msec 4 msec
> > 2 10.0.10.3 4 msec 0 msec *
> >
> >
> > Now I add a VL between BOTTOM and R5(which has the s0/0 connection to
> > BOTTOM)
> >
> > R5#
> > BOTTOM#
> > 00:08:04: %OSPF-4-ERRRCV: Received invalid packet: mismatch area ID, from
> > backbo
> > ne area must be virtual-link but not found from 10.1.1.1, Serial0/0
> >
> > BOTTOM(config)#router os 10
> > BOTTOM(config-router)#area 1 vir 200.200.200.200
> > BOTTOM(config-router)#^Z
> > BOTTOM#
> > BOTTOM#sh ip ro
> > Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> > D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> > N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> > E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> > i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
> > area
> > * - candidate default, U - per-user static route, o - ODR
> > P - periodic downloaded static route
> >
> > Gateway of last resort is not set
> >
> > 192.192.192.0/32 is subnetted, 1 subnets
> > O 192.192.192.192 [110/1573] via 10.1.1.1, 00:00:02, Serial0/0
> > 10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
> > O 10.0.10.0/24 [110/1572] via 10.1.1.1, 00:00:02, Serial0/0 <<<Now
> > via the serial!!!!
> > O 10.2.10.10/32 [110/65] via 10.2.0.2, 00:00:02, Serial0/1
> > C 10.2.0.0/24 is directly connected, Serial0/1
> > O IA 10.3.0.0/24 [110/1620] via 10.1.1.1, 00:00:02, Serial0/0
> > C 10.1.2.0/24 is directly connected, Ethernet0/0
> > C 10.1.1.0/24 is directly connected, Serial0/0
> > BOTTOM#
> >
> >
> >
> >
> >
> >
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