From: Rick Burts (burts@xxxxxxxxxxxxxx)
Date: Mon Jan 29 2001 - 19:03:40 GMT-3
Mike
There is a pretty well known behavior of demand circuit activating
when the environment includes some other protocol on the router and
redistribution of that protocol into OSPF. Briefly the other protocol
sees the ISDN going down as a routing change which is redistributed into
OSPF which brings the link up to advertise the change. You can look into
the archives for more extensive discussions of this.
Rick
Rick Burts, CCSI CCIE 4615 burts@mentortech.com
Mentor Technologies 240-568-6500 ext 6652
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On Mon, 29 Jan 2001, Mike S. Lee wrote:
> In trying to use the Demand circuit option I still see the dialer dialing.
> Debugging Q931 is see that the dial cause is 224.0.0.5 which is all spf
> routers. I thought that using an ospf demand circuit should have suppressed
> all LSA's from going across this line. Can someone either explain this
> behavior or provide a working config that uses demand circuits and only
> comes up when the primary link fails? Any debug outputs would be helpful as
> well.
>
> thanks
>
> mike
> At 11:53 AM 1/29/2001 -0800, Kevin Baumgartner wrote:
> >I have heard this a few times but I have had no problems using it with OSPF.
> >Maybe this was a limitation in earlier 12.0 images.
> >
> > Kevin
> >
> >
> >At 01:18 PM 1/29/01 -0600, Wade Edwards wrote:
> > >As I recall dialer watches work only with IGRP and EIGRP. If you need OSP
F
> > >then the demand circuit is the best way to go.
> > >
> > >-----Original Message-----
> > >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > >Jeremy Gray
> > >Sent: Sunday, January 28, 2001 2:34 PM
> > >To: ccielab@groupstudy.com
> > >Subject: RE: ISDN Backup without the backup interface command?
> > >
> > >
> > >
> > >A demand circuit is useful if you really msut run OSPF over an ISDN line.
> > >
> > >A better answer to this problem is to use a dialer watch-list, a very coo
l
> > >facility used to trigger DDR when a 'watched' route is absent in the routi
ng
> > >table.
> > >
> > >This is great for a number of reasons.
> > >
> > >1) Packet switched networks are not the best at telling a DTE when there's
a
> > >problem in the cloud. Examples being ATM and FR
> > >Interface may stay up/up even if the remote is down.
> > >
> > >2) You can place a DDR in a place further into your network rather than on
> > >the same router as a critical link and still have DDR work when the link
> > >fails if the routes being watches originate beyound the point of failure.
> > >
> > >Regards,
> > >
> > >Jeremy.
> > >
> > >PS: Joined today. Lab date March 8th.
> > >-----Original Message-----
> > >From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> > >Robert DeVito
> > >Sent: 28 January 2001 16:39
> > >To: obuba@bellatlantic.net; mac38456@pegasus.cc.ucf.edu;
> > >ccielab@groupstudy.com
> > >Subject: Re: ISDN Backup without the backup interface command?
> > >
> > >
> > >
> > >
> > >Another thing to keep in mind is that ospf demand circuit will cause the
> > >isdn circuit to come up when there is a topology change.. So don't be
> > >shocked when it comes up every once and awhile.
> > >
> > >Robert
> > >
> > >----Original Message Follows----
> > >From: "Nnanna Obuba" <obuba@bellatlantic.net>
> > >Reply-To: "Nnanna Obuba" <obuba@bellatlantic.net>
> > >To: "Miguel A. Ciena" <mac38456@pegasus.cc.ucf.edu>,
> > ><ccielab@groupstudy.com>
> > >Subject: Re: ISDN Backup without the backup interface command?
> > >Date: Sun, 28 Jan 2001 10:10:43 -0500
> > >
> > >That's no trick, use ospf demand circuit
> > >
> > >
> > >Nnanna Obuba, CCIE # 6586
> > >www.nantech.com
> > >Online lab for CCIE Preparation
> > >----- Original Message -----
> > >From: "Miguel A. Ciena" <mac38456@pegasus.cc.ucf.edu>
> > >To: <ccielab@groupstudy.com>
> > >Sent: Sunday, January 28, 2001 9:07 AM
> > >Subject: ISDN Backup without the backup interface command?
> > >
> > >
> > > > Between R3 and R5 I got a ISDN link. I want to configure my ISDN to =
> > > > back-up my frame relay connection between R3 and R5...Here is the Tric
k:
> > >=
> > > > Without using Floating Static and without using the Back-up interface
=
> > > > command..My Frame and ISDN are in OSPF area 0...
> > > >
> > > > any ideas..
> > > >
> > > >
> > > >
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