From: kasturi cisco (kasturi_cisco@xxxxxxxxxxx)
Date: Mon Aug 19 2002 - 17:45:43 GMT-3
Brian(s),
So in that case the ISDN link would remain in an up state for a long time
as its expected to due to primary link being down. Is that right ? So
there is a chance that the ISDN link may not go down at all if there is
traffic from either side. The interesting traffic from remote site will
reset the idle timeout and link will be up - instead of 120 secs timeout.
Thanks for the explanations. I had read these docs (read it once again)
but not paid close attention to the finer details.
Kasturi.
>From: "Brian McGahan" >To: "'Brian Dennis'" , "'kasturi cisco'" , ,
>Subject: RE: Backup Interface and IGRP >Date: Mon, 19 Aug 2002 15:12:17
-0500 > > Yep, I forgot about that part. Like Brian said, you can >either
define interesting traffic on the remote side, and leave off the >dial
string, or leave off the interesting traffic, and set the idle >timeout
to excessively high. You can also say "dialer idle-timeout 0", >which is
the effectively infinite I believe. > > On a side note Brian, you'd be
surprised how many times a >customer has asked me to design a dial backup
method for them without >using OSPF demand circuit, dialer-watch,
snapshot, or static routes >though. ;) > >Brian McGahan, CCIE #8593
>Director of Design and Implementation >brian@cyscoexpert.com >
>CyscoExpert Corporation >Internetwork Consulting & Training
>http://www.cyscoexpert.com >Voice: 847.674.3392 >Fax: 847.674.2625 >
>-----Original Message----- >From: Brian Dennis [mailto:brian@5g.net]
>Sent: Monday, August 19, 2002 3:02 PM >To: 'kasturi cisco';
brian@cyscoexpert.com; ciscoworks2001@yahoo.com; >ccielab@groupstudy.com
>Subject: RE: Backup Interface and IGRP > >If you have no interesting
traffic defined on the remote router what >will stop him from dropping
the line after 120 seconds even if the local >router has data to send?
120 seconds is enough time to allow routing >updates but the line will
never be up for more than 120 seconds. In the >real world this would
create problems by having the line constantly go >up and down. Try and
download a large file when this is happening ;-) > >Check out some of the
dial backup examples on CCO. You'll see that it is >normal to just leave
off the dial string on the remote router. >
>http://www.cisco.com/warp/public/793/access_dial/backup_11047.html
>http://www.cisco.com/warp/public/793/access_dial/bri_isdn_11049.html
>http://www.cisco.com/warp/public/793/access_dial/britobribackup.html >
>The high idle timeout on the remote end is just a "stupid lab trick" if
>the question didn't allow the use of the dialer-list command. > >Brian
Dennis, CCIE #2210 (R&S/ISP Dial) > > > >-----Original Message-----
>From: kasturi cisco [mailto:kasturi_cisco@hotmail.com] >Sent: Monday,
August 19, 2002 12:34 PM >To: brian@5g.net; brian@cyscoexpert.com;
ciscoworks2001@yahoo.com; >ccielab@groupstudy.com >Subject: RE: Backup
Interface and IGRP > >Brian, >If i understand u right - are u saying that
its better to have no dial >string rather than "no dialer list" . what
problem might it create ? > >Also why do u say very hi idle timeout ? i
thought the idle timeout >should be same on both sides. So if the idle
timer expires on the local >(calling sisde) then when the timer expires
it drops the line, right ? >even if its 120 secs the updates would be
exchanged and it would work. >Am i getting confused ? >Kasturi. > >From:
Brian Dennis > >To: 'Brian McGahan' , 'kasturi cisco' ,
ciscoworks2001@yahoo.com, >ccielab@groupstudy.com > >Subject: RE: Backup
Interface and IGRP > >Date: Mon, 19 Aug 2002 11:38:51 -0700 > > > >If you
don't have a dialer-list you need to take into account that the > >remote
router will not have any interesting traffic. If the local >router >
>with the backup interface command makes an ISDN call, the longest the >
>line will be up is 120 seconds due to the fact that the remote router >
>doesn't have any interesting traffic and is dropping the line when its >
>idle-timeout expires. I would suggest just not giving the remote router
> > >a number to call or at least adjusting the dialer idle-timeout to >
>something really high. > > > >Brian Dennis, CCIE #2210 (R&S/ISP Dial) >
> > >-----Original Message----- > >From: nobody@groupstudy.com
[mailto:nobody@groupstudy.com] On Behalf Of > > >Brian McGahan > >Sent:
Monday, August 19, 2002 10:35 AM > >To: 'kasturi cisco';
ciscoworks2001@yahoo.com; ccielab@groupstudy.com > >Subject: RE: Backup
Interface and IGRP > > > >Kasturi, > > > > Not a restrictive dialer-list,
*no* dialer-list. If the local > >interface is in standby mode, there
will never be a circumstance that > >the remote side is allowed to dial
in. Even if it does dial in, the > >local side will not answer since the
interface is in standby. > > > >Brian McGahan, CCIE #8593 > >Director of
Design and Implementation > >brian@cyscoexpert.com > > > >CyscoExpert
Corporation > >Internetwork Consulting & Training >
>http://www.cyscoexpert.com > >Voice: 847.674.3392 > >Fax: 847.674.2625 >
> > >-----Original Message----- > >From: kasturi cisco
[mailto:kasturi_cisco@hotmail.com] > >Sent: Monday, August 19, 2002 12:30
PM > >To: brian@cyscoexpert.com; ciscoworks2001@yahoo.com; >
>ccielab@groupstudy.com > >Subject: RE: Backup Interface and IGRP > > >
>Armand, > > > >Looks like the IGRP traffic is the interesting traffic
from remote end. > > >As Brian wrote since there is no need for this
traffic to dialin deny > >this traffic at the remote end. Create a
restrictive dialer list and > >deny this traffic - may be dialer list 1
deny igrp any any or may be ip > > >any any ? > >When u deny this traffic
it wont dialin. There wont be a need as u are > >using backup interface
so when the local side (side where backup > >interface cmd is placed) has
physical interface in down state it will > >dial out and establish
connection. > >Am i right ? this should work as u say snapshot routing is
not > >allowed.Which case study is this ? > >Let us know. > > > >Good
Luck, > >Kasturi. > > > > >From: "Brian McGahan" > > >To: "'Armand D'" ,
"'kasturi cisco'" , > > >Subject: RE: Backup Interface and IGRP > >
>Date: Mon, 19 Aug 2002 11:30:28 -0500 > > > > > >Armand, > > > > > >
Don't put interesting traffic on the remote side. Assuming this > > >is
only a point-to-point dial scenario, and the local side is in > >backup,
> > >there will never be a case where the remote side should be dialing
at > > > >all. > > > > > >Also, "debug dialer packet" will give you more
detailed information > > >about what traffic is interesting or not. > > >
> > > > > >HTH > > > > > >Brian McGahan, CCIE #8593 > > >Director of
Design and Implementation > > >brian@cyscoexpert.com > > > > >
>CyscoExpert Corporation > > >Internetwork Consulting & Training > >
>http://www.cyscoexpert.com > > >Voice: 847.674.3392 > > >Fax:
847.674.2625 > > > > > > > > >-----Original Message----- > > >From:
nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf >Of > > >
> >Armand D > > >Sent: Monday, August 19, 2002 11:06 AM > > >To: kasturi
cisco; ccielab@groupstudy.com > > >Subject: Re: Backup Interface and IGRP
> > > > > >Hi, > > > > > >I am prevented from using snapshot and
watch-lists. > > >I'm trying to use the backup interfcace so this router
> > >only dials when it loses connectivity on its primary > > >port. It
appears that igrp brings the call back up > > >from the remote side from
the show dialer cmd: Dial > > >reason: ip (s=135.4.35.6,
d=255.255.255.255) > > > > > >Is there any way to prevent this call back
issue ? > > > > > >Thanks, > > > > > >Armand > > > > > >--- kasturi cisco
wrote: > > > > Armand, > > > > > > > > If u look at the debugs (maybe
easier in lab to use > > > > the show dialer cmd as > > > > this
generates less amount of info than > > > > debug)...gives similiar info
for > > > > troubleshooting...The show dialer cmd will show the > > > >
dial reason which helps > > > > to find why link is going UP/DOWN > > > >
> > > > When u look at the output it shows bcast as dest > > > > address
> > > > > > > > > >1w3d: BRI0/0: ip (s=135.4.35.5, d=255.255.255.255), >
> > > >186 bytes, outgoing interesting (list 100) > > > > > > > > The
router with Src address shown above is > > > > generating IGRP routing
updates > > > > and hence these updates. To the best of my knowledge > >
> > the ways to do this is > > > > > > > > - if u deny igrp routing
updates and use static > > > > routes (may not be a option) > > > > > > >
> - USe snapshot routing as this prevents the DV > > > > protcols form
sending updates > > > > every "update interval" > > > > > > > > I cant
think of any other way ? anyone care to add > > > > ?? > > > > > > > >
HTH.Are u prevented from using Snapshot ?? by the Q > > > > or Secenario.
> > > > > > > > Good luck, > > > > kasturi. > > > > > > > > > >
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