[rancid] [patch] Filter oscillating VLAN port membership when VTP Pruning

Rhett Hooper rhooper at wheelercat.com
Wed Feb 2 23:04:06 UTC 2011

On 2/2/2011 1:55 PM, Daniel Roesen wrote:
> On Tue, Feb 01, 2011 at 02:08:39PM -0700, Rhett Hooper wrote:
>> I really wish the output from "show vlan brief" was truly brief.
>> I couldn't find a way to get IOS to just show a list of the VLAN
>> numbers with their names, so I made the following patch to rancid.
>> It filters the VLAN port membership from the output of "show vlan"
>> when it finds that VTP Pruning is enabled.
> Actually, is there a good reason not to filter it unconditionally?
> I mean, it's (potentially) dynamic operational state, not
> configuration.

None that I know of.  I think it is useful information to get a list of 
VLAN numbers with their names, but an actual change in the configuration 
shows up as a "switchport access vlan" statement in the output from 
"show running-config".

> Suggest to filter unconditionally.

Which is what I now do in our environment since VLAN port membership 
"dynamic operational state" can change for reasons other than VTP 
pruning.  We use 802.1X authentication to dynamically assign a VLAN, too.

We have a mix of Cisco 6509, 3750, 3560, 3550, and 2960 switches running 
a fairly uniform set of IOS versions.  I didn't think that was a wide 
enough sample to say that the regular expressions that filter the ports 
from the "show vlan" output will work for everyone.

Rhett Hooper
Network Administrator
Wheeler Machinery Co.

More information about the Rancid-discuss mailing list