From: Paglia, John (USPC.PCT.Hopewell) (JPaglia@NA2.US.ML.com)
Date: Wed Oct 23 2002 - 16:15:39 GMT-3
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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