From: Cameron, John (johcamer@cisco.com)
Date: Sat May 03 2003 - 11:43:51 GMT-3
Bob,
Yes it can - see below:
How a Recently-Inserted Switch Can Cause Network Problems:
This problem occurs when you have a large switched domain, which is all in
the same VTP domain, and you want to add one switch in the network.
This switch was previously used in the lab and a good VTP domain name was
entered. It was configured as a VTP client, and connected to the rest of the
network. Then, the ISL link was brought up to the rest of the network. In
just a few seconds, the whole network is down. What could have happened?
The configuration revision of the switch you inserted was higher than the
configuration revision of the VTP domain. Therefore, your
recently-introduced switch, with almost no configured VLANs, has erased all
VLANs through the VTP domain.
This will happen whether the switch is a VTP client or a VTP server. A VTP
client can erase VLAN information on a VTP server. You will know that this
has happened when many of the ports in your network go into inactive state,
but continue to be assigned to a non-existing VLAN.
Solution:
Quickly reconfigure all of the VLANs on one of the VTP servers.
What to Remember:
Always make sure that the configuration revision of all switches inserted
into the VTP domain is lower than the configuration revision of the switches
already in the VTP domain.
http://www.cisco.com/warp/customer/473/21.html#vtp_ts_rec_ins
HTH
JDC
-----Original Message-----
From: Robert L. DuBell [mailto:bobdu11@cox.net]
Sent: Saturday, May 03, 2003 6:29 AM
To: kym blair; gitsyoung@yahoo.co.jp; ccielab@groupstudy.com
Subject: RE: VTP domain name -- important
Kym,
If the server is in Client Mode it will not modify the VLAN information of
the other switches. If it was in Server Mode and was put in production then
there would be a problem for sure.....but you're safe if you put it in
production in client mode....Bob
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
kym blair
Sent: Friday, May 02, 2003 11:29 PM
To: gitsyoung@yahoo.co.jp; ccielab@groupstudy.com
Subject: Re: VTP domain name -- important
Tom,
You asked a very interesting question. Suppose you have a live network and
all the switches are in domain "CCIE". One or two of the switches are in
Server Mode (so you can add and remove VLANs). Over a few months, you have
added and removed VLANs so that the CCIE Domain is at Revision 8 (all
switches will show same Revision number as they learn the VLANs).
Now, suppose you have a new switch that you practice with in your lab. You
configure it for Domain "CCIE", and add and remove practice vlans for a few
days (so you are at Revision 12), then set it to Client Mode. You are still
in Domain CCIE, Revision 12, Client Mode.
Now you attach this "Client" to the production network. Whoooa ... all the
switches will forget their real VLANs and learn the Client's VLANs because
it has the highest Rev number. Recovering from this accident can be very
serious because all the port assignments will be lost; it may be easy to
type all the lost VLANs back into the vlan database, but it will be hard
remembering which ports were assigned to each VLAN!
EXCEPTION: any switch configured in Transparent Mode will not learn the new
VLANs, and will not lose their VLANs.
SOLUTION: before attaching a switch to a production network, check what Rev
number the new switch is in. If it is higher than the production network,
change the domain name to something else (e.g., "TEST"), exit (sot the
change is applied), then change it back (e.g., "CCIE"). Then verify it has
lowered the Rev number to "0".
HTH, Kym
>From: Tom Young <gitsyoung@yahoo.co.jp>
>Reply-To: Tom Young <gitsyoung@yahoo.co.jp>
>To: ccielab@groupstudy.com
>Subject: VTP domain name
>Date: Sat, 3 May 2003 11:00:21 +0900 (JST)
>
>Some work was found in cisco homepage as blow,
>
>"If a switch has no VTP domain name configured, it will
>receive the VTP domain name from an
>attached switch through the trunk port (if one is
>available). The switch configuration defaults to a
>VTP server, without a VTP domain name. When a new set of
>Catalysts are connected by a trunk, you
>only need to configure the VTP domain name on one switch.
>The other switches will be notified of
>the VTP domain name through the first summary
>advertisement."
>
>But if I had set the vtp domain name in two switchs with
>TWO diffirent name , which one will be advertised?
>
>Thanks alot
>
>__________________________________________________
>Do You Yahoo!?
>Yahoo! BB is Broadband by Yahoo! http://bb.yahoo.co.jp/
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