From: Scott Morris (smorris@ipexpert.com)
Date: Sat Jan 26 2008 - 03:48:00 ARST
STP (and CDP) at its heart is a L2 multicast frame. You are copying things
from one port to another and expecting it to be forwarded. is the VLAN you
are forwarding it on something you're trunking as well? (e.g. are there
multiple paths for that multicast frame to take since you are tunneling it?)
If so, you have a loop and your switch is unhappy with you! :)
switchport trunk allowed vlan remove (#) will help you!
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
A Cisco Learning Partner - We Accept Learning Credits!
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of John
Sent: Thursday, January 24, 2008 12:55 PM
To: ccielab@groupstudy.com
Subject: l2 tunnel
I'm curious as to why this is happening, again I'm missing some logic.
SW1 connects to SW3 through 3 trunk interfaces f0/16-18. I make f0/16 a
dot1q tunnel. I get connectivity(iti works the way it's supposed to. I was
also supposed to shut f0/17-18. I didn't.
Now I add an l2 cdp tunnel to f0/16 and the port goes into err disable. I
shut f0/16-18 and then no shut f0/16 works. I know its STP but I can't see
the logic and since I'm on rack time I'm not gonna look up the awnser till
after I'm done.
Any help would be greatly appreciated
JG
This archive was generated by hypermail 2.1.4 : Fri Feb 01 2008 - 10:38:01 ARST