[rbridge] Avoiding sending multiple IS-IS Hellos tagged with all the VLAN tags

[Dinesh G Dutt]

Hi Radia,

Radia Perlman wrote:
> I had a conversation with Anoop, and he is (quite understandably)
> uneasy about sending IS-IS Hellos tagged with every VLAN. So he
> made the following suggestion, which I think makes sense.
>
> a) declare that bridges must be configured
> so that VLAN 1 (default VLAN) must not be
> partitioned on a layer 2 cloud. We will detect the misconfiguration
> if it occurs (see d)) so that we at least do not have loops, but TRILL 
> will not
> stand on its head to support what will be declared a gross misconfiguration.
>   
This will not fly. We originally had such a scheme a long time ago in 
our switches. We got so much flak from customers that we eventually had 
to back away from it. A single VLAN across the entire L2 cloud is 
unacceptable.

Also the number of deployments using GVRP/MVRP/VTP is quite 
insignificant. A significant (if not most) number of customers have 
deliberately turned off running these protocols to manage VLANs.

However, I'm sympathetic to Anoop's point and do think it is acceptable 
to partition the network in case of misconfiguration, but we MUST avoid 
loops at all costs. Let me think a little more,

Dinesh

-- 
We make our world significant by the courage of our questions and by 
the depth of our answers.                               - Carl Sagan