From: anand kumar (akkumar1000@xxxxxxxxx)
Date: Tue Jan 16 2001 - 17:44:42 GMT-3
The purpose of 'ip ospf demand-circuit' is to prevent
periodic hello updates for keeping the dial-up link
active when there is no interesting traffic. It does
this by setting the DNA bit across the OSPF dialup
neighbors
--- Curtis Phillips <phillipscurtis@netscape.net>
wrote:
> I agree with Julie. The idea is to keep the
> interface down by supressing
> hellos and not aging the LSAs on either side of the
> link. If there is a change
> then the BRI will dial and pass the new LSAs
> afterwhich it should drop and
> continue in demand mode.
>
> As for the initial question... Are there other
> routing protocols running on
> the routers hosting the BRIs? If so, can you post
> the whole configs?
>
>
>
>
> "Connary, Julie Ann" <jconnary@cisco.com> wrote:
> Andrew,
>
> define what you mean by connected. The whole purpose
> of demand circuit is
> to only allow routing change
> updates - supress hellos - between the
> point-to-point neighbors established
> across the ISDN link and supress the periodic
> updates -
> hence the DNA. This way the ISDN circuit only comes
> up for interesting
> traffic
> when the router needs to route that traffic across
> the ISDN link, i.e.
> another better route not being available or if the
> ospf database
> is changing - i.e. a routing change update.
>
> With ip opsf demand circuit you do not need to
> filter OSPF traffic in your
> dialer-list.
>
> Julie Ann
>
>
> At 11:10 AM 1/15/2001 -0600, Andrew Short wrote:
> >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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