an easier way to find the problem is to debug ospf flooding and/or lsa
generation. Then you do not
have to go through the pain of waiting for the link to be quiet for each
interface as you bring it up.
Julie Ann
At 02:31 PM 3/27/2001 -0600, Alan Basinger wrote:
Your correct Z filter the bri subnet from redistribution into IGRP and your
LSA's should not continue to bring the link up.
Alan
-Original Message-
From: Mask Of Zorro [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, March 27, 2001 2:32 PM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED];
[EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED];
[EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED];
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Subject: Re: bri flapping with demand cirquit/igrp redistribution
Redistribution brings it up.
What happens is, the link is brought up and OSPF forms an adjacency. Then,
since it is a demand circuit, periodic LSA's are squelched and OSPF routes
associated with those LSA's do not age out of the routing table. Then, the
layer 2 portion of the link drops, since there is no interesting traffic.
Once the link drops, whatever protocol you are redistributing into OSPF sees
it's link drop, and changes its tables in accordance with the topology
change. This change gets redistributed into OSPF, and OSPF floods LSA's out
announcing the change. These LSA's bring up the link while OSPF converges.
Then, after a while, things are stable again, and the link drops - and guess
what? That's right! The whole thing starts again...
There are ways to stop it.
Z
From: "George Zhang" [EMAIL PROTECTED]
Reply-To: "George Zhang" [EMAIL PROTECTED]
To: [EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED],
[EMAIL PROTECTED], [EMAIL PROTECTED],
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Subject: Re: bri flapping with demand cirquit/igrp redistribution
Date: Tue, 27 Mar 2001 13:50:52 -0600
I also had the same problem a few days ago. Here is how I fixed it:
1. Isolate the problem by shutting down all other interfaces besides the
interfaces
between the two related routers;
2. Disable all other routing protocols (non-OSPF ones);
3. Turn off IGRP redistribution to OSPF;
3. Now, verify the ISDN demand circuit. It should be quiet now.
4. Now, start unshut the interfaces you have shut down one by one and
verify
that the ISDN demand circuit. It should might come up briefly but it
should go
down and keep quiet after some interfaces are unshut. If the ISDN
line
keep dialing, you should know which interface is causing the problem.
5. If the ISDN line is still quiet after you unshut all interfaces, turn on
your other router
protocols such as IGRN, RIP, etc one by one. Again, verify the IDN
line after
each change as above.
5. If the ISDN line is still quiet after you enable all other routing
protocols, turn on your
redistribution one by one. Again verify ISDN line along the way.
If you follow these steps, you should be able to pin down what is causing
your ISDN
line to stay up.
Hope it helps.
George Zhang
"Donald B Johnson Jr" [EMAIL PROTECTED] 03/27/01 03:33PM
It may keep the connection open though even after there is no intresting
traffic.
Don
- Original Message -
From: Alan Basinger [EMAIL PROTECTED]
To: Chris Larson [EMAIL PROTECTED]; perez claude-vincent
[EMAIL PROTECTED]; Ya Wen [EMAIL PROTECTED]; Patrick
Murphy [EMAIL PROTECTED]; Leah Lynch [EMAIL PROTECTED]; 'Jay
Chandradas' [EMAIL PROTECTED]; 'Bob Boone' [EMAIL PROTECTED];
[EMAIL PROTECTED]; [EMAIL PROTECTED]
Sent: Saturday, March 24, 2001 8:37 AM
Subject: RE: bri flapping with demand cirquit/igrp redistribution
CDP may work at layer 2 but if the line is brought up because of web
traffic
CDP packets would then traverse the line consume a small amount of
bandwidth.
I have installed a few ISDN DDR VPN's without turning off CDP and never
had
and issue but also didn't think about the bandwidth consumption at the
time.
Alan
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
Chris Larson
Sent: Saturday, March 24, 2001 9:00 AM
To: perez claude-vincent; Ya Wen; Patrick Murphy; Leah Lynch; 'Jay
Chandradas'; 'Bob Boone'; [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: RE: bri flapping with demand cirquit/igrp redistribution
It may not, I have just always disabled it on dialer links as a habit.
It
makes sense that it shouldn't since the dialer-list defines layer 3
traffic
only. You could always put an access-list on the dialer interface
permitting
all traffic with the log statement to see exactly what is trying to get
accross the line. It will output to the console if you are consoled in.
That
may help you to see what is bringing the line up.
