[c-nsp] Maximum spannig tree instances

[sthaug at nethelp.no]

> > "switchport trunk allowed vlan *ADD* 1234"
> >
> > is one of our favourites, tho... :-)
> 
> I've been reluctant to roll that out on all the trunks due to the damage 
> that could be caused if someone got careless and dropped the 'add' while 
> adding a new VLAN to a trunk.

With suitable TACACS verification of commands you can make *only*
the following available:

switchport trunk allowed vlan none
switchport trunk allowed vlan add ...
switchport trunk allowed vlan remove ...

which takes care of forgetting the add keyword. Done at the company
we're in the process of merging with, works great.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no