From: Randall Scheffer (rscheffe@xxxxxxxxxxx)
Date: Wed Jun 14 2000 - 17:25:10 GMT-3
True but that is not a funtion of Eigrp..it is a dial backup scheme. Also
please see the disadvantages listed below..cut straight from CCO in quotes.
"Once the secondary link is up, at the expiration of each idle timeout, the
primary link is rechecked. If the primary link remains down, the idle timer
is indefinitely reset. "
Even if there is no interesting traffic the link stays up...not part of the
desired result.
"The router is configured with a dynamic routing protocol such as Interior
Gateway Routing Protocol (IGRP) or Enhanced IGRP is configured. Only
Enhanced IGRP and IGRP are currently supported."
Only support Eigrp and Igrp...and only for IP.
regards,
Randall
-----Original Message-----
From: abdul_rahim@ccsi.canon.com [mailto:abdul_rahim@ccsi.canon.com]
Sent: Wednesday, June 14, 2000 2:08 PM
To: Randall Scheffer
Cc: 'DHBrown@PipeLine.com'; Randall Scheffer; ccielab@groupstudy.com
Subject: RE: OSPF On-demand Circuit
EIGRP can do it
If you use dialer watch-lists
The point is that you donot have to add any static routes at all
and you have a list configured which monitors some routes that must be
present in the routing table
and as soon as they get vanished ( because of any link or router failures
in between )
It will dial the specified number
Thanks
Abdul
Randall Scheffer <rscheffe@allstar.com> on 06/14/2000 09:28:19 AM
Please respond to Randall Scheffer <rscheffe@allstar.com>
To: "'DHBrown@PipeLine.com'" <DHBrown@PipeLine.com>
Randall Scheffer <rscheffe@allstar.com>
ccielab@groupstudy.com
cc: (bcc: Abdul Rahim/IS Operations/Operations/CCSI)
Subject: RE: OSPF On-demand Circuit
Yes...this acl will prevent OSPF from ever bringing the line up on its own.
loose it. The whole concept of ON-DEMAND CIRCUIT is to allow a dynamic
protocol to run dynamically over ISDN. EIGRP can't do it, Rip can't
do...as
far as I know OSPF is the only prot that has such a method, (key point
here)
that does not require STATIC ROUTES.
try it you'll like it,
Randall
-----Original Message-----
From: David H. Brown [mailto:DHBrown@PipeLine.com]
Sent: Wednesday, June 14, 2000 10:26 AM
To: 'Randall Scheffer'; ccielab@groupstudy.com
Subject: RE: OSPF On-demand Circuit
Randall,
I setup my dialer access-list:
- access-list 103 deny ospf any host 224.0.0.5 log
- access-list 103 permit ip any any
which will make the local OSPF LSA traffic NOT bring up the line, but does
not prevent the router from receiving the updates once the BRI line is up.
The problem I am seeing now is that without a static route, the BRI does
not
consider any traffic interesting (when Serial goes down) because it does
not
know to route it through the BRI -- the OSPF table has not been built yet.
Now, if I manually bring it up once and let it stay on, the DNA routes
remain and it works perfectly. But, if power goes down and back up on that
router then it will NOT dial the BRI line because the DNA routes are gone.
Is there a better solution than floating static?
David
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Randall Scheffer
Sent: Wednesday, June 14, 2000 9:43 AM
To: 'David H. Brown'; ccielab@groupstudy.com
Subject: RE: OSPF On-demand Circuit
If you deny OSPF traffic, then you deny OSPF routes too. Just let ospf
demand circuit do its work. Everything else remains the same.
Randall
-----Original Message-----
From: David H. Brown [mailto:DHBrown@PipeLine.com]
Sent: Monday, June 12, 2000 10:53 PM
To: kmiho@lycos.ne.jp; ccielab@groupstudy.com
Subject: RE: OSPF On-demand Circuit
Kmiho,
If your access-list is setup correctly to deny OSPF traffic, it should not
come up until it is needed. I just restarted my 'backup' router to see if
it would bring up the ISDN line, and it did not when it started. It should
not come up until the Serial line fails and interesting traffic tries to
route.
Hmmm, this is interesting: there are no DNA routes in the OSPF database
after restarting (I suppose I could achieve the same result by 'clear ip
route *'), and now the router does not know to route through the ISDN as a
backup once the Serial line goes down. It works if I force it open once by
pinging the other side of the ISDN circuit because it gets the routes then,
but that's not a good practice in real life. What did I miss here?
Statics
aren't allowed, how else can I fill that OSPF table?? Seems like having it
come up once when it starts would be a great idea! BTW, I am running
11.2(22a) and 11.2(12).
David
(RTP lab 6/15)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
kmiho@lycos.ne.jp
Sent: Sunday, June 11, 2000 6:28 AM
To: ccielab@groupstudy.com
Subject: OSPF On-demand Circuit
Is it true that when you use the "ip ospf demand-circuit" command,
the link will be brought up once even though the network topology is
stable(or else the other side of the bri0 will not make it to OSPF
database?). I do not have the isdn simulator to verify that but I do
notice the following message appear even though the ethernet link
between R1 and R2 is not broken.
********
bri0: ip (s=R1's bri0, d=224.0.0.5), interesting(ip PERMIT)
bri0: sending broadcast to ip (R2's bri0)
********
Can somebody clarify this? Thanks in advance.
--- R1(bri0)------------- isdn ------------(bri0)R2----
(e0) (e0)
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