From: Yinka Daramola (o_daramola@hotmail.com)
Date: Thu Feb 06 2003 - 20:38:40 GMT-3
I'm sure this had been dealt with before, but I think the problem with
option 2 is that the isdn link will never go down once activated.
The ospf hello packets will keep it up since the link will never be idle
enough to for the idle timer to kick in.
However, I would think if you manipulted the ospf hello and the dialer idle
timers a bit you could get a working link, it may not be an optimal solution
though.
Yinka Daramola, MCSE, CCNP RHCE
Red Hat Inc.
----- Original Message -----
From: "sam" <sam@avtechusa.com>
To: <ccielab@groupstudy.com>
Sent: Thursday, February 06, 2003 2:46 PM
Subject: ISDN again - Preventing OSPF traffic from bringing up a secondary
line
> Sorry for the lengthy post. got some doubts and wanted to clear 'em up.
>
> QN: I got another one here...
> BRI is configured as a backup for the serial link.
> Let us say that I do not want to bring up my BRI interface which is
> defined in the same OSPF area as my primary link.
>
> ____ ____
> | |s0 -------------- s0| |
> | r1 | | r2 |
> | |bri0 ---------- bri0| |
> ~~~~ ~~~~
>
> I can go into say R2's BRI0 and configure
>
> (a) ip ospf demand-circuit
>
> (b) deny ospf traffic to bri0 (seen below in excerpt from Doc. CD on
> Dialer Watch)
>
> access-list 101 remark Define Interesting Traffic
> access-list 101 deny ospf any any
> !Mark OSPF as uninteresting.
> !This will prevent OSPF hellos from keeping the link up.
> Access-list 101 permit ip any any
> dialer-list 1 protocol ip list 101
> !Interesting traffic is defined by access-list 101.
> !This is applied to BRI0 using dialer-group 1.
>
>
> Question: Do both actions provide the same results? The most obvious
> scenario would be to use
> Ip ospf demand-circuit, in my opinion. or even better, use
> dialer watch or floating static.
>
> But what are the implications then ? (a) or (b) ?
>
> Am I correct to say that the dialer group command is used to define
> interesting traffic. Denying OSPF traffic means that the ISDN connection
> will not be brought up by OSPF hellos. Once the DDR has been activated
> on the BRI interfaces, the dialer group's restrictions on OSPF traffic
> WILL NOT apply to traffic flowing through the BRI link.
>
> TIA
> Sam Sena
> .
.
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