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RE: DDR question. posted 10/23/2002
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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/ip_r
/iprprt2/1rdospf.htm#xtocid19
Watch the wrap!!!

John

> -----Original Message-----
> From:	enginedrive2002 [SMTP:enginedrive2002@xxxxxxxx]
> Sent:	Wednesday, October 23, 2002 12:51 PM
> To:	ccielab@xxxxxxxxxxxxxx
> 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.