> With OSPF traffic as uninteresting, something has to initiate the call.
> The probe traffic can keep the line up after OSPF converges, but when
> the line initially drops, the router will not have a route to the remote
> network to send the probe traffic.  The SNMP kicks up the line, and then
> the OSPF can converge.  If you just point the probe at the other end of
> the ISDN connection, it would keep the line up the whole time.
>
> Marvin Greenlee, CCIE#12237, CCSI# 30483 Network Learning Inc
> marvin@ccbootcamp.com www.ccbootcamp.com (Cisco Training)
>
>
> -----Original Message-----
> From: Gustavo Novais [mailto:gustavo.novais@novabase.pt]
> Sent: Thursday, August 25, 2005 2:27 AM
> To: marvin greenlee; ccielab@groupstudy.com
> Subject: RE: Dialer backup without demand circuit
> [bcc][faked-from][bayes]
>
> Hummm, interesting solution!
>
> Didn't think about SNMP... Do you really need it? The probes are always
> on, so whenever you lose primary link you will always have traffic to
> kick in, if you point the probes to the remote isdn side.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> marvin greenlee
> Sent: quinta-feira, 25 de Agosto de 2005 0:44
> To: Gustavo Novais; ccielab@groupstudy.com
> Subject: RE: Dialer backup without demand circuit
> [bcc][faked-from][bayes]
>
> We had a similar discussion a few days ago on another message board.
> OSPF over ISDN without using demand circuit, backup interface, or dialer
> watch:
>
> OSPF - not interesting traffic
> SMNP - interesting
> ICMP - interesting
>
>
> ***  Step 1 - kick up the line if primary goes down ***
>
> snmp-server enable traps snmp linkdown
> snmp-server host 56.56.56.5 TEST
> ! The address 56.56.56.5 is the address of the remote side of the ISDN.
> ! SNMP traffic needs to be interesting in your dialer list.
>
> ! Sending the trap for link-status is on by default. Disable for other
> interfaces.
>
> int bri0/0
> no snmp trap link-status
>
> int dialer 1
> no snmp trap link-status
>
> int eth0/0
> no snmp trap link-status
>
> ! Make sure that it is enabled for the Serial interface.
>
> int ser0/1
> snmp trap link-status
>
>
>
>
>
>
> *** Step 2 - keep the line up if primary is down ***
>
> Traffic Generation - keep the line up
>
> Configure a SAA probe to ping a remote network.
>
> rtr 2
> type echo prot ip 2.2.2.2
> frequency 15
> rtr schedule 2 life forever start now
>
> Note: ICMP traffic will need to be defined as interesting for ISDN.
>
> ***
> The probe traffic would normally be sent out the serial link, because
> that is where the route to the distant network would be. When the serial
> line goes down, the SNMP trap triggers the dial, and OSPF can establish
> an adjacency and learn a route for the distant network via the ISDN
> line. With ICMP traffic defined as interesting, the probe traffic will
> be sent out the ISDN interface, and will keep the line up. When the
> serial line comes back up, OSPF will reconverge, and the route via the
> serial network will be preferred. Since the ICMP traffic is no longer
> passing over the ISDN connection, the ISDN connection will time out
> after the idle timeout value.
>
> Marvin Greenlee, CCIE#12237, CCSI# 30483 Network Learning Inc
> marvin@ccbootcamp.com www.ccbootcamp.com (Cisco Training)
>

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