From: Scott Morris (smorris@internetworkexpert.com)
Date: Fri Aug 08 2008 - 16:44:29 ART
I have not labbed this one up yet, but from my perusal of the lab, I would
say that it's an intended effect based on configuration choices that are
made otherwise.
L2 Protocol Tunneling can be quite tricky in its applications and how to
troubleshoot things along the way!
So my guess is that the effect was intentional, although I haven't chatted
with Brian about this yet! :) I know in labs I have written that I knew
the problem was going to occur, but was plenty happy to let students run
smack into it.
It's very much like cleaning a full glass door/window REALLY well just to
see how many people run into it! (grin) (Yes, most CCIE instructors have
some sort of sadistic streak going)
Scott
_____
From: Igor Manassypov [mailto:imanassypov@rogers.com]
Sent: Friday, August 08, 2008 2:41 PM
To: smorris@internetworkexpert.com; 'cciestudy'; 'Igor Manassypov'; 'GS
CCIE-Lab'
Subject: RE: IE Lab 20
So Scott, is this a planted or accidental bug in this lab?
Scott Morris <smorris@internetworkexpert.com> wrote:
How about determining where the tunnel loop is in the network? Spanning
tree should be able to work nicely in a proper setting. Sometimes these
loops are a severe pain to figure out, but once you diagram and trace it,
you'll "get it".
:)
HTH,
Scott Morris, CCIE4 #4713, JNCIE-M #153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
Senior CCIE Instructor
smorris@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Outside US: 775-826-4344
Knowledge is power.
Power corrupts.
Study hard and be Eeeeviiiil......
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
cciestudy
Sent: Friday, August 08, 2008 11:43 AM
To: 'Igor Manassypov'; 'GS CCIE-Lab'
Subject: RE: IE Lab 20
I believe you are correct. Turning off keepalives just stopped the
interfaces from going errdisable. I believe turning on STP over the q-in-q
tunnel was the fix.
SW4 F0/19, f0/21, f0/13, f0/15
L2protocol-tunnel stp
From a Layer 2 standpoint this lab made my head spin.
_____
From: Igor Manassypov [mailto:imanassypov@rogers.com]
Sent: Friday, August 08, 2008 10:35 AM
To: cciestudy; 'Igor Manassypov'; 'GS CCIE-Lab'
Subject: RE: IE Lab 20
Hmm, whats the mechanism behind the interface keepalives that triggers the
interface to shutdown? Besides, I really doubt that just by disabling the
interface keepalive you avoid the loop, its just might stop going into
errdisable but the loop will still occur if there is one (?)
cciestudy wrote:
I finished that lab a few weeks ago. All I can say is it was a bugger to
solve. The IE message board has some good insight into why it was occurring.
I believe turning off interface keep-alives resolved the looping problem. I
believe it was SW4, F0/13, F0/15, F0/19, F0/21. Also, I tried doing
L2protocol-tunnel on STP also...
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Igor
Manassypov
Sent: Friday, August 08, 2008 9:58 AM
To: GS CCIE-Lab
Subject: IE Lab 20
Hi Gang,
Has anyone done internetwork expert's lab 20 recently? I am having a hard
time on the first section with STP where it keeps flipping interfaces to
err-disabled mode due to 'loopback error'. I am wondering if anyone was able
to solve it.
Thanks!
Igor M., M.Eng, P.Eng
Network Architect
Blogs and organic groups at http://www.ccie.net
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