[nsp] VLAN database propagation

[Liviu Pislaru]

Gert Doering wrote:

>Hi,
>
>On Thu, Mar 18, 2004 at 09:46:27AM -0500, Warren Kumari wrote:
>  
>
>><rant>
>>I have made a whole bunch of feature requests asking that the default 
>>mode be changed to transparent, but apparently Cisco believes 
>>plug-and-play is more important than reliability. How many people on 
>>the list have had someone plug in an old / test switch that has a 
>>higher VLAN version number than their production switches and lost all 
>>of their VLANs because of this?
>>    
>>
>
>Yep.  Had one of the old switches for testing, deleted all the VLANs on it
>(due to "cleanup config, no need to keep around") - later reconnected it
>to the production network, VLAN database serial number higher than on the
>other ones -> boom, network dead.
>
>Overall I *do* like VTP, because it's so convenient, but you need to make
>sure that the number of people that connect and configure new VTP members
>is small, and that all those people know what they are doing.
>
>gert
>
>  
>
Hi,

It is very important to verify a switch's VTP configuration before 
connecting it to a production network. If the switch has been previously 
configured or used elsewhere , it might already be in a VTP server mode 
with a VTP config revision number that is higher than other switches in 
the production VTP domain.
In that case, other switches will listen and learn from the new switch 
because it has a higher revision number and must know more recent 
information. This could cause all other switches in the domain to delete 
all their active VLANs and that is the reason you lose the configuration 
on the switches from the VTP domain.

leev


-- 

Cu consideratie,
-- 
Liviu Pislaru - Tech Department
CCNA - Registered Linux User #308824
Romania Data Systems - NOC in Bucharest
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