From: Kevin Baumgartner (kbaumgar@xxxxxxxxx)
Date: Thu Sep 21 2000 - 13:03:04 GMT-3
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 aga
in.
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 172.17.2.253 255.255.255.25
5 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 ci
rcuits but my theory
is that OSPF demand circuits only suppress internal LSA's not external LSA's. H
ence 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 > > > > > > --- Daniel Keller <DMKeller@comdisco.com> wrote: > > > Because the BRI's are in area 0, OSPF updates will > > > constantly be triggering the ISDN line. How do > > you > > > keep this line from always coming up? > > > > > > >>> Kevin Baumgartner <kbaumgar@cisco.com> > > 09/19/00 > > > 09:42PM >>> > > > Why do say that OSPF demand circuit won't cut it? > > > The key to using demand circuit is > > > > > > 1. Define the bandwidth on the BRI interface to > > be > > > less that serial interface > > > 2. If doing any redistribution on either of the > > BRI > > > routers > > > filter such that IP subnet between the two BRI > > > router > > > interfaces doesn't get redistributed. If you > > let > > > this route > > > through the BRI interface will flap because of > > > routing updates. > > > 3. Define OSPF demand circuit on only one router > > > (optional). > > > > > > The other two methods to do this is like you said > > > dialer watch-list > > > and backup interface. > > > > > > Kevin > > > > > > > > > > > > > > Hey bud, got a good config for the following ? > > > > > > > > s0 & bri0 are in the same area 0 of OSPF > > > > > > > > what's a good dial backup config for this for > > when > > > s0 goes down without bri0 > > > > flapping? demand circuit doesn't seem to cut > > it, > > > floating statics are out of > > > > the question, leaving only dialer watch-list > > (IOS > > > 12.3 & higher) or backup > > > > interface - but what other way is there if any > > !? > > > > > > > > > > > > Mike L. Chase > > > > Sr. Network Architect > > > > ISG: Information Services Group > > > > Broadcom Corporation World Headquarters, BLDG > > > A-1050 > > > > 16215 Alton Parkway, Irvine, California > > > 92618-3616 > > > > > > > > > >OFFICE:949-585-6057|CELL:949-283-4254|FAX:949-585-6227 > > > > > > > > > > > > -----Original Message----- > > > > From: nobody@groupstudy.com > > > [mailto:nobody@groupstudy.com]On Behalf Of > > > > Kevin Baumgartner > > > > Sent: Tuesday, September 19, 2000 7:10 PM > > > > To: Steve McNutt > > > > Cc: ccielab@groupstudy.com > > > > Subject: Re: Hello, new on list > > > > > > > > > > > > Yes in theory ISDN is simple but I would be > > able > > > to do the following > > > > and have practiced the following on routers. > > > > > > > > 1. OSPF on demand circuit > > > > 2. Dial backup > > > > 3. Appletalk over ISDN (and how to filter so > > ISDN > > > is not up all the time) > > > > 4. IPX over ISDN (also how to filter so ISDN is > > > not up all the time) > > > > 5. Dialer watch > > > > 6. PPP Multilink > > > > 7. PPP CHAP/PAP > > > > 8. PPP Callback > > > > 9. Snapshot routing > > > > > > > > Kevin > > > > > > > > > > > > > > practice ISDN? ISDN is pretty simple to > > > configure and troubleshoot. DOD > > > > > routing using rotary groups and dialer > > profiles > > > gives me fits though hehe. > > > > > If you don't build your configs in the correct > > > order the dialer interfaces > > > > > never seem to work right. > > > > > > > > > > > > > > > > > > > > -----Original Message----- > > > > > From: nobody@groupstudy.com > > > [mailto:nobody@groupstudy.com]On Behalf Of > > > > > Kevin Baumgartner > > > > > Sent: Tuesday, September 19, 2000 9:30 PM > > > > > To: jix@netrue.com > > > > > Cc: ccielab@groupstudy.com > > > > > Subject: Re: Hello, new on list > > > > > > > > > > > > > > > If you don't practice ISDN, ATM or FR you > > have > > > no chance of passing. > > > > > They have to be part of your practice lab. > > > > > > > > > > Kevin > > > > > > > > > > > > > > > > > > > > > > > > > > > >
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