From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Mon Sep 13 2004 - 13:22:51 GMT-3
John,
I agree with the results of the book answer key. They do however state
in the discussion section that using a dialer-list is acceptable (normal
deny routing protocol/permit ip any dialer-watch method). This
configuration would however not garnish the full 5 points, but only 3.
Probably, like most people, I setup ISDN to test connectivity first and
then tweaked it to the requirements. Hence, having the dialer-list that
denied RIP.
But I do agree, the only reason to bring up the link is dialer-watch, so
don't use dialer-list or deny any in dialer-list. This = more points.
8)
andy
-----Original Message-----
From: john matijevic [mailto:matijevi@bellsouth.net]
Sent: Monday, September 13, 2004 9:17 AM
To: Edwards, Andrew M; 'Joseph Rothstein'; ccielab@groupstudy.com
Subject: RE: ISDN Cisco Press Lab 1
Hello Andy,
The link should only come up via a dialer watch, should not come up with
BGP traffic. Why did you permit all IP? You should not have done that
the answer key does not have that. The dialer list only defines
interesting traffic that will bring up the link. In this case the only
reason that the link will come up is if both of those networks are
missing. The answer-key has to deny ip any on R1, so that the dialer
watch is the only reason it will bring up the link.
"I think that the only reason they did a dialer-list with deny any is
because that would ensure no traffic would bring up the link, and the
ONLY thing that would is the dialer-watch."
Answer: Yes this is correct.
"In my case, I didn't set the metrics to prefer the frame connection
until the end of the ISDN section. Hence, once activated (local ping or
dialer-watch), the ISDN connection was always up because of equal metric
load distribution by R4 moving BGP traffic between R2 and R6/R8."
Answer: local ping should not activate isdn, only the dialer watch. The
line should stay up until those networks are restored that dialer watch
is watching.
Also make sure you put the dialer idle-timeout to 0, on R4, so that the
line does not disconnect after 120 seconds, and reconnect.
IF you need any additional help with these labs, be sure to register on
my website and post in the forum.
Sincerely,
John Matijevic, CCIE #13254, MCSE, CNE, CCEA
CEO
IgorTek Inc.
151 Crandon Blvd. #402
Key Biscayne, FL 33149
Hablo Espanol
305-321-6232
http://home.bellsouth.net/p/PWP-CCIE
-----Original Message-----
From: Edwards, Andrew M [mailto:andrew.m.edwards@boeing.com]
Sent: Monday, September 13, 2004 12:00 PM
To: john matijevic; Joseph Rothstein; ccielab@groupstudy.com
Subject: RE: ISDN Cisco Press Lab 1
Joseph/John-
I just went through this lab yesterday.
I think that the only reason they did a dialer-list with deny any is
because that would ensure no traffic would bring up the link, and the
ONLY thing that would is the dialer-watch.
Myself, I did the dialer-list that denied RIP and permited all IP.
In my case, I didn't set the metrics to prefer the frame connection
until the end of the ISDN section. Hence, once activated (local ping or
dialer-watch), the ISDN connection was always up because of equal metric
load distribution by R4 moving BGP traffic between R2 and R6/R8.
At least that's what I thought...
HTH,
andy
-----Original Message-----
From: john matijevic [mailto:matijevi@bellsouth.net]
Sent: Saturday, September 11, 2004 11:57 AM
To: 'Joseph Rothstein'; ccielab@groupstudy.com
Subject: RE: ISDN Cisco Press Lab 1
Hello Joseph,
Based on the question, it is telling you that the 2 networks (Vlan3 and
Lo0) should be accessible if the frame fails, so the question is
basically saying that both networks must be down before the router dials
out so that is why the answer key has both networks watched. I can see
where you want to just watch the 1 loopback to cover the both networks,
because if the loopback were gone, that would mean that the frame would
be down, and would have to use the isdn line, but in this case the
question is specifically asking you to watch those 2 networks.
There is no need to use the dialer-list in this example, he just has it
to deny the traffic. As long as you have the dialer-watch list, the link
should come up fine with the routes are missing. The dialer list defines
the interesting traffic, so there would be no reason to define a
dialer-list or to just have the dialer-list but to just say to deny ip
any any, as the book suggests, in this example.
"But with all interesting traffic denied, which would reset the idle
timer (which would happen with rip updates), the ISDN goes down because
of no interesting traffic, but then comes right back up because of
dialer-watch. Is this acceptable"
Can you please show me a debug if you have the ISDN going down because
of no interesting traffic?
The dialer watch triggers because an absence of a route, it should not
go down because of no interesting traffic. The only reason it should go
down is if the watch routes appear back up in the routing table.
I have implemented per the answer key and it worked as it should, if you
want I can re-lab this up and provide debugs for you.
Sincerely,
John Matijevic, CCIE #13254, MCSE, CNE, CCEA
CEO
IgorTek Inc.
151 Crandon Blvd. #402
Key Biscayne, FL 33149
Hablo Espanol
305-321-6232
http://home.bellsouth.net/p/PWP-CCIE
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Joseph Rothstein
Sent: Saturday, September 11, 2004 5:23 AM
To: ccielab@groupstudy.com
Subject: ISDN Cisco Press Lab 1
Greetings to all.
I am just starting to work on these labs, and have come across an
interesting problem with the ISDN configuration in Lab 1.
First off, I don't see that it is necessary to watch two routes in the
watch-list. Why not just watch the loopback? Why two? Just seems to
complicate the situation.
The author's use of the dialer-list here is thoroughly confusing. Page
39 tries to justify the use of this, but for me something seems amiss.
The text says "otherwise, any traffic will potentially keep the line up
after initiated." Well, the line is going to stay up no matter if there
is interesting traffic or not. The absence of the watched route
guarantees this. But with all interesting traffic denied, which would
reset the idle timer (which would happen with rip updates), the ISDN
goes down because of no interesting traffic, but then comes right back
up because of dialer-watch. Is this acceptable? Or should we assume that
there would be other traffic over this line, other than RIP that would
keep this ISDN up? There are of course easy solutions for this, such as
making all traffic interesting, or setting the idle timer to 0.
Any thoughts? John?
Joe
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