From: Andrew Short (ashort@xxxxxxxxxxxxxxx)
Date: Mon Jan 15 2001 - 14:10:49 GMT-3
The ip ospf demand-circuit will NOT suppress hellos if the circuit is not
currently connected. It will only suppress hellos once the circuit is
connected. Hellos are used on a demand circuit to bring the circuit up!
You have to do an "access-list 101 deny ospf..." statement in your
dialer-list to keep hellos from bringing up the link. The demand circuit
configuration causes the transmitting router to set the "DoNotAge" bit to
one, and if the routers beyond the DDR circuit honor the DNA bit (As Cisco
routers do), then that LSA will not age throughout your topology, and the
demand-circuit configuration will have done it's job.
Summarized from Doyle, Page 491-493
On Mon, 15 Jan 2001, Horton, Jeff wrote:
> I was testing the use of ip ospf demand-circuit in the lab and noticed that
> when I use dialer-profiles with a dialer 0 interface and use the
> dialer-string command, the ip ospf demand-circuit command is not suppressing
> hellos. I have to use the list 101 with an access list-to filter the
> multicasts. I applied the demand-circuit statement on D0 and on BRI 0/0,
> neither works. When using the dialer-map statement with legacy DDR, I have
> no problems.
>
> Can anyone see what's wrong?
>
> Thanks,
>
> Jeff
>
> R1
>
> interface BRI0/0
> bandwidth 64
> no ip address
> ip directed-broadcast
> encapsulation ppp
> dialer pool-member 1
> isdn switch-type basic-ni
> isdn spid1 0835866101 8358661
> isdn spid2 0835866301 8358663
> no cdp enable
> ppp authentication chap
> !
> interface Serial0/1
> no ip address
> no ip directed-broadcast
> !
> interface Dialer0
> ip address 172.168.12.1 255.255.255.0
> no ip directed-broadcast
> encapsulation ppp
> dialer remote-name R2
> dialer idle-timeout 10
> dialer pool 1
> dialer-group 1
> no cdp enable
> ppp authentication chap
> ppp multilink
>
>
>
> R2
>
> interface BRI0/0
> bandwidth 64
> no ip address
> ip directed-broadcast
> encapsulation ppp
> ip ospf demand-circuit
> dialer pool-member 1
> isdn switch-type basic-ni
> isdn spid1 0835866201 8358662
> isdn spid2 0835866401 8358664
> no cdp enable
> ppp authentication chap
> !
> interface Serial0/1
> no ip address
> no ip directed-broadcast
> shutdown
> !
> interface Dialer0
> ip address 172.168.12.2 255.255.255.0
> no ip directed-broadcast
> encapsulation ppp
> ip ospf demand-circuit
> dialer remote-name R1
> dialer idle-timeout 10
> dialer string 8358661
> dialer pool 1
> dialer-group 1
> no cdp enable
> ppp authentication chap
> ppp multilink
> !
>
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