From: Sam Munzani (smunzani@xxxxxxxxx)
Date: Thu Sep 21 2000 - 17:54:34 GMT-3
I think that's it. Last time I had my filters properly
done and this time I didn't pay much attention.
Good troubleshooting Kevin,
Sam
--- Kevin Baumgartner <kbaumgar@cisco.com> wrote:
> I think I have solved the problem. I have set my
> routers to be as close
> as possible to what you where doing.
>
> IGRP
> \ AREA 2
> AREA 3
> R1----s0/0----------------------------- s0/0
> ---- R2---e0/0 ------- e0/0 ---- R4
> A | |
> |
> R | | AREA 2
> |
> E | -----BRI2/0 ------------------------
> BRI1/0 --
> A |
> 0 |
> R3
>
> So the first thing I tried was defining the OSPF
> virtual-link on R1 and R2 for Area3
> with OSPF demand circuit. It worked as expected. The
> ISDN line would come up
> once to do a topology update and then the line would
> go down and stay down.
>
> The next step was to try redistributing IGRP into
> OSPF on R1. This caused the
> line to always stay up. As soon as the dialer
> timeout expired it would call again.
>
> So I did some debugging to see what was happening
>
> debug dialer
> debug ip ospf lsa-generation
>
> And I saw a message of "Generating external LSA for
> 172.17.2.253 255.255.255.255 Type 5"
>
> So I created a route-map that deny any
> redistribution of the 172.17.2.240 (ISDN Network)
> into OSPF.
> Worked like a charm. The ISDN link stayed down and
> only came up when I took the Serial link down.
> Still a little fussy what happening here with
> redistribution and OSPF demand circuits but my
> theory
> is that OSPF demand circuits only suppress internal
> LSA's not external LSA's. Hence the need for
> this route filter as redistributing other routing
> protocols into OSPF is going to generate external
> LSA
> updates.
>
> Configurations
>
> R1
>
> interface Ethernet0/0
> ip address 172.17.1.3 255.255.255.240
> !
> interface Serial0/0
> bandwidth 2000
> ip address 172.17.2.1 255.255.255.240
> clockrate 2000000
> !
> interface BRI2/0
> bandwidth 56
> ip address 172.17.2.254 255.255.255.240
> encapsulation ppp
> ip ospf demand-circuit
> dialer map ip 172.17.2.253 name R2 broadcast
> 87772002
> dialer-group 1
> isdn switch-type basic-5ess
> ppp authentication chap
> !
> username R2 password cisco
> dialer-list 1 protocol ip permit
> !
> router ospf 1
> area 0 range 172.17.1.0 255.255.255.0
> area 2 range 172.17.2.0 255.255.255.0
> area 2 virtual-link 172.17.3.1
> redistribute igrp 1 metric 1 subnets route-map
> igrp-ospf
> passive-interface TokenRing1/0
> network 172.17.1.3 0.0.0.0 area 0
> network 172.17.2.1 0.0.0.0 area 2
> network 172.17.2.254 0.0.0.0 area 2
> network 172.17.193.1 0.0.0.0 area 0
> !
> access-list 1 permit 172.17.2.240 0.0.0.15
> access-list 2 permit any
> !
> route-map igrp-ospf deny 10
> match ip address 1 <<<<< Deny
> sending LSA external onto ISDN.
> !
> route-map igrp-ospf permit 20
> match ip address 2
> !
>
> router igrp 1
> redistribute ospf 1 metric 10000 200 255 1 1500
> passive-interface Ethernet0/0
> passive-interface Serial0/0
> passive-interface BRI2/0
> network 20.0.0.0
> network 172.17.0.0
> !
> ip classless
>
> R2
> ----
>
> interface Ethernet0/0
> ip address 172.17.3.1 255.255.255.252
> !
> interface Serial0/0
> bandwidth 2000
> ip address 172.17.2.2 255.255.255.240
> !
> interface BRI1/0
> bandwidth 56
> ip address 172.17.2.253 255.255.255.240
> encapsulation ppp
> ip ospf demand-circuit
> dialer map ip 172.17.2.254 name R1 broadcast
> 87772001
> dialer-group 1
> isdn switch-type basic-5ess
> ppp authentication chap
> !
> username R1 password cisco
> dialer-list 1 protocol ip permit
> !
> router ospf 1
> area 2 virtual-link 172.17.2.254
> network 172.17.2.2 0.0.0.0 area 2
> network 172.17.2.253 0.0.0.0 area 2
> network 172.17.3.1 0.0.0.0 area 3
>
>
>
>
> At 05:26 PM 9/20/00 -0700, you wrote:
> >That's correct. It is very close to a real lab
> >scenario according to some romours I heard.
> >
> >An the thing is, I had it working once. This time
> it
> >doesn't work.
> >
> >Sam
> >--- Daniel Keller <DMKeller@comdisco.com> wrote:
> > > The problem is that area 2 is a virtual link.
> > > Because of this, LS updates will always keep the
> > > line dialing. Can you place the bri connections
> > > into a different area? If not you will need to
> find
> > > an alternative, such as using backup interface.
> Is
> > > this from a lab that you have?
> > >
> > > Dan Keller
> > >
> > > >>> Sam Munzani <smunzani@yahoo.com> 09/20/00
> > > 05:50PM >>>
> > > Hi Group,
> > >
> > > I have attached my configs with e-mail. Tell me
> what
> > > am I doing wrong? ISDN keeps flapping. Scenario
> is
> > > as
> > > below.
> > >
> > > Grumpy--(Bri 0) ------ (Bri 0 )-- Sleepy
> > >
> > > The BRI link is in OSPF area 2. I used OSPF
> demmand
> > > circuit and also used no peer neighbor route.
> > > Bandwidth is not specified on serial link so it
> will
> > > be default T1 for frame link.
> > >
> > > I have also attached "ip ospf data" results on
> each
> > > router. I had it working some time ago but this
> time
> > > it doesn't work.
> > >
> > > Rather than throwing some hints please justify
> > > proper
> > > methodology for this configuration. I am sure
> > > everybody will get hit by this scenario in some
> > > flavor
> > > so it is important.
> > >
> > > Sam
>
=== message truncated ===
=====
Regards,
Sam Munzani
sam@munzani.com
This archive was generated by hypermail 2.1.4 : Thu Jun 13 2002 - 08:25:00 GMT-3