From: Brian McGahan (brian@cyscoexpert.com)
Date: Sat Jul 05 2003 - 18:01:17 GMT-3
Navin,
Yes, you can run dialer watch and OSPF demand circuit at the
same time. However, if OSPF is not defined as interesting traffic, OSPF
cannot bring up the DDR link in order to report a change in topology.
As I said, the point of running demand circuit is that everyone can keep
an accurate view of the routing topology while minimizing the
unnecessary usage of the DDR circuit solely for routing protocol
traffic.
HTH,
Brian McGahan, CCIE #8593
Director of Design and Implementation
brian@cyscoexpert.com
CyscoExpert Corporation
Internetwork Consulting & Training
Toll Free: 866.CyscoXP
Fax: 847.674.2625
> -----Original Message-----
> From: Navin Parwal [mailto:parwal@vsnl.com]
> Sent: Friday, July 04, 2003 8:20 PM
> To: Brian McGahan
> Cc: Harmit
> Subject: Re: OSPF Demand Circuit
>
> Hi Brian ,
> Can we run both demand circuit and dialer watch at the same time
> , if we do so wont we have to deny OSPF in the access list in
order to
> run dialer watch . would our configuration then be correct as in case
of
> demand circuit we need to specify the OSPF traffic as interesting .
> please comment.
>
> thanks,
>
> Navin Parwal
>
> ----- Original Message -----
> From: "Brian McGahan" <brian@cyscoexpert.com>
> To: "'ccie2be'" <ccie2be@nyc.rr.com>; "'Group Study'"
> <ccielab@groupstudy.com>
> Sent: Friday, July 04, 2003 11:11 PM
> Subject: RE: OSPF Demand Circuit
>
>
> > Jim,
> >
> > This TAC document is wrong. The purpose of running OSPF demand
> > circuit is to maintain an accurate view of the routing topology,
while
> > minimizing the amount of time that your DDR link is up solely due to
> > routing protocol traffic.
> >
> > By denying OSPF as interesting traffic, adjacency cannot be
> > maintained over the DDR link unless it is up for some other reason.
> > When the link goes down due to no interesting traffic passing over
the
> > link within the idle timeout, OSPF adjacency will be lost as soon as
the
> > dead interval expires.
> >
> > When running OSPF demand circuit, OSPF *should* be specified as
> > interesting traffic.
> >
> > HTH,
> >
> > Brian McGahan, CCIE #8593
> > Director of Design and Implementation
> > brian@cyscoexpert.com
> >
> > CyscoExpert Corporation
> > Internetwork Consulting & Training
> > Toll Free: 866.CyscoXP
> > Fax: 847.674.2625
> >
> >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
Behalf
> > Of
> > > ccie2be
> > > Sent: Friday, July 04, 2003 5:22 AM
> > > To: Group Study
> > > Subject: OSPF Demand Circuit
> > >
> > > Hi,
> > >
> > > After checking the archieves, I didn't find anything that
specifically
> > > addressed this question, so here goes.
> > >
> > > I thought that when a BRI interface is configured as an ip ospf
> > > demand-circuit, it will automatically suppress ospf hello's as
long as
> > the
> > > interface is configured as a p2p or p2m ospf network type.
> > >
> > > However, in the example at
> > > http://www.cisco.com/warp/public/129/config-bri-map.html , it
shows an
> > > access
> > > list being used to prevent ospf hello's in addition to the ip ospf
> > > demand-circuit command being configured.
> > >
> > > Is it really necessary (or just sometimes necessary) to use an
access
> > list
> > > to
> > > deny ospf hello's (packets addressed to 224.0.0.5) when one side
of
> > the
> > > isdn
> > > circuit is configured as an ip ospf demand circuit? If so, why is
> > that?
> > > Also, if the access-list in addtion to the ip ospf demand circuit
is
> > only
> > > needed in certain situations, what are those situations?
> > >
> > > Thanks, Jim
> > >
> > >
> > >
> >
This archive was generated by hypermail 2.1.4 : Wed Aug 06 2003 - 06:52:25 GMT-3