From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Tue Aug 27 2002 - 18:55:27 GMT-3
Raj/Kasturi
Ideally
* Demand circuits are meant to trigger when there is a change in LSA.
* Making OSPF uninteresting will not only 'not' trigger the link, but it may
also be a violation of condition in the LAB.
* The other thing is the sequence/methodology how you do it, as stated below
* Get basic connectivity working and put in ip ospf demand-circuit on one
end (no harm in putting it on both sides of the link)
* If a classful protocol is also running on any of the routers connected by
demand circuit, make sure you install 'no peer neighbor route' on BRI/dialer
interface (no harm in doing on both ends)
* Either do step 2 or , when redistributing the class ful into OSPF, filter
out the /32 host route that is generated.
* Make the OSpf cost to be very high, something like 9999 so that in
presence of alternate paths, this is the highest cost, and hence lowest
preferred path.
* If the network on dialer/bri falls under same major network as the
classful protocol, make sure you do a passive interface bri/dialer under the
classful protocol.
* If possible make the area containing 'demand circuit' as stub area, if you
'can' do so (if it is possible within defined criteria in the lab /
production environment)
rgds
Nick
----- Original Message -----
From: kasturi cisco <kasturi_cisco@hotmail.com>
To: <raj.bahad@totalise.co.uk>; <ccielab@groupstudy.com>
Sent: Wednesday, August 28, 2002 3:20 AM
Subject: Re: IP OSPF DEMAND CIRCUIT
> Raj,
>
> When i have configured OSPF i have never made this un-interesting . I
> have seen this too, but what i think is if we make it uninteresting then
> how will the updates traverse the link whenever there is changes that
> need to go thru. OSPF demand ckt is to ensure the hellos and other
> keepalive packets dont bring the demand ckt up.
>
> Also when we do configure demand ckt the "Hellos suppressed" should be
> seen with the interface.
>
> Good Luck,[IMAGE]
> Kasturi.
>
> >From: Raj Bahad >Reply-To: Raj Bahad >To: ccielab@groupstudy.com
> >Subject: IP OSPF DEMAND CIRCUIT >Date: Tue, 27 Aug 2002 11:23:07 +0100 >
> >Hi Group, > >Please could any of you help clarify a couple of
> questions...I've been through >the CCO extensivley but still am not clear
> on certain combinations. > >When using IP OSPF DEMAND CIRCUIT, is there
> any need to also restrict the >dialer-list to deny OSPF?...I've come
> across configs where in ceratin cases >ospf is being classicfied as
> un-interesting traffic and in other cases its >not. > >My understanding
> of IP OSPF DEMAND cictuit is that it essentially prevents the >LSA's from
> aging so that when the link goes back down, the router still has a
> >complete routing table. Now if you also specify ospf as un-interesting
> >traffic, would that not prevent ospf updates from traversing the ISDN
> link? > >Cheers, > >Raj.
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