From: Tim Fletcher (tim@fletchmail.net)
Date: Wed Oct 23 2002 - 20:52:39 GMT-3
If you don't deny OSPF then the link will come up any time there is a topology change (or other interesting traffic, but not for hellos). If you do deny OSPF then a topology change will not bring up the circuit and routes will not get propagated. It all depends on what you're trying to accomplish.
-tim
At 03:46 PM 10/23/02 -0400, Larson, Chris wrote:
>I am not disagreeing with what you are saying.
>
>
>It's just that I have never had to create a dialer-list excluding OSPF as
>interesting traffic to keep the ISDN line quiet when using demand-circuit.
>If you do a dialer-list ip protocol ip permit and put the demand circuit on
>the bri interface..... assuming everything else is configed properly the
>circuit should remain quiet until there is a topo change.
>
>
>
>> -----Original Message-----
>> From: Paglia, John (USPC.PCT.Hopewell) [SMTP:JPaglia@NA2.US.ML.com]
>> Sent: Wednesday, October 23, 2002 3:16 PM
>> To: 'Larson, Chris'; 'enginedrive2002'; ccielab@groupstudy.com
>> Subject: RE: DDR question.
>>
>> The dial-list dictates what initiates the call...demand-circuit affects
>> activity after the call is made. 2 different animals.
>>
>> The ACL says 'do not start the link if the ip packet is a ospf-based ip
>> packet, but if it's any other ip packet, let 'er rip'. Then, when for
>> instance a ping brings the line up, OSPF sends hellos and lsa's to
>> establish
>> neighborings and LSA exchanges, after which demand-circuit says 'hey,
>> there's only so much BW here, so let's just assume we're cool, and keep
>> our
>> proverbial mouths shut unless there is an LSA change'.
>>
>> Hopefully I'm helping here!!
>> John
>>
>> > -----Original Message-----
>> > From: Larson, Chris [SMTP:CLarson@usaid.gov]
>> > Sent: Wednesday, October 23, 2002 3:00 PM
>> > To: 'Paglia, John (USPC.PCT.Hopewell)'; 'enginedrive2002';
>> > ccielab@groupstudy.com
>> > Subject: RE: DDR question.
>> >
>> > If periodic hello's and lsa's are suppressed so they do not flood the
>> > demand circuit. AND
>> >
>> > "only periodic hellos and refreshes of LSA's once the call is made"
>> >
>> > Then why is the 101 list needed? It says that hello's and lsa's will not
>> > be sent until after the call is made? Why do you need to supress them
>> > twice?
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: Paglia, John (USPC.PCT.Hopewell) [SMTP:JPaglia@NA2.US.ML.com]
>> > Sent: Wednesday, October 23, 2002 2:08 PM
>> > To: 'enginedrive2002'; ccielab@groupstudy.com
>> > Subject: RE: DDR question.
>> >
>> > The definition of 'demand-circuit' as per the 12.1 cmd. ref.:
>> > Periodic hellos are suppressed and periodic refreshes of LSAs do not
>> flood
>> >
>> > the demand circuit. It allows the underlying datalink layer to be closed
>>
>> > when the topology is stable.
>> > ...only periodic hellos and refreshes of LSA's once the call is made.
>> > Thus,
>> > you put the 'deny ospf any any' cmd. in to keep hello's from acting as
>> the
>> >
>> > 'interesting traffic' that can initialize a link. Once non-ospf traffic
>> > brings up the link, demand-circuit kicks in.
>> >
>> > Here's the link:
>> >
>> <http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/i> > p_r>
>> > /iprprt2/1rdospf.htm#xtocid19
>> > Watch the wrap!!!
>> >
>> > John
>> >
>> > > -----Original Message-----
>> > > From: enginedrive2002 [SMTP:enginedrive2002@yahoo.ca]
>> > > Sent: Wednesday, October 23, 2002 12:51 PM
>> > > To: ccielab@groupstudy.com
>> > > Subject: DDR question.
>> > >
>> > > Would someone read the doc link below, and answer a few questions:
>> > > <http://www.cisco.com/warp/public/129/config-bri-map.html>
>> > >
>> > > 1. On router maui-soho-01, "ip ospf demand-circuit" is configured
>> under
>> > > BRI
>> > > interface, why in the example, access-list 101 still need to have
>> "deny
>> > > ospf
>> > > any any"? I have never test OSPF demand-circuit at before, but I
>> "guess"
>> >
>> > > with
>> > > the "ip ospf demand-circuit" command, it will already suppress the
>> hello
>> >
>> > > packets. Would someone confirm this?
>> > >
>> > > 2. On router maui-nas-05, under BRI interface, the example doesn't
>> > > configure
>> > > any number to dial, which mean it could only answer the call. But why
>> in
>> >
>> > > the
>> > > example, it has "dialer-group", "dialer-list" command to define
>> > > interesting
>> > > traffic? Just to reset the idle-timer while the BRI link is up? Any
>> > other
>> > > purpose here?
>> > >
>> > > Thank you!
>> > >
>> > >
>> > > Regards,
>> > >
>> > >
>> > > E.D.
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