[rbridge] Avoiding sending multiple IS-IS Hellos tagged with allthe VLAN tags
Radia.Perlman at sun.com
Tue Jul 31 11:18:30 PDT 2007
I don't understand that problem. What you're describing might argue for
bridges using a unique
spanning tree per VLAN in order to optimize traffic flow for that VLAN,
but I don't
see what it has to do with wanting to partition VLANs.
Dinesh G Dutt wrote:
> Radia Perlman wrote:
>> I'd like to understand what problem customers are attempting to solve
>> partitioned VLANs, and what hardship it would present to require at
>> least one of the
> The primary problem with having a VLAN everywhere is that the root of
> the spanning tree moves around leading to non-optimal forwarding in
> enterprise networks. Enterprise networks are carefully engineered
> networks and in the event of failure, they want to localize the
> effects as much as possible. So, they want each VLAN to be localized
> and roots where they want it to be. Having a common VLAN messes up
> that arrangement. Also, VLAN 1 is the default VLAN when a switch comes
> up and there is typically lots of customer data on it.
>> VLANs to *not* be partitioned. With TRILL, if a customer eventually
>> all bridges, the customer will not be able to partition VLANs anymore.
> As I raised it in the meeting, this is a side-effect that has not been
> considered before and needs to be carefully thought through. I don't
> think many people are aware of this issue with TRILL that doesn't
> exist with 802.1Q bridges today.
>> Also, from
>> what Anoop was explaining to me, the GVRP protocol would automatically
>> configure the switch-to-switch links to join all the islands of
>> VLANs. So it would
>> seem as though it can't be that fatal to solving customer problems to
>> *one* VLAN on a layer 2 cloud to not be partitioned.
> GVRP is not deployed by a significant majority of customers.
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