[rbridge] VLAN registration

[Eastlake III Donald-LDE008]

Hi Dinesh,

There have been posts to this list stating that there are customers that
want and use standards based dynamic VLAN registration.

It seems to me that the completely broken state of dynamic VLAN
registration that was in the TRILL base protocol draft version -06
needed to be fixed. If you have two 802.1Q bridges, say X and Z, and put
an Rbridge conformant to the -06 spec between them or if you have three
such bridges connected in sequence, say X - Y - Z, and replace Y with
such an Rbridge, the Rbridge will generally break any dynamic VLAN
registration going on between these bridges, whether you are using GVRP
or the new MVRP. How can such network damage be consistent with our
goals of incremental deployment and VLAN support?

It seemed to me that Rbridges should be forward looking, so I thought
they should support the newer MVRP, and Rbridges should be simple, so I
didn't even bother to think much about how you could support both GVRP
and MVRP (although you could do that as the frames seem to be easily
distinguishable). That's why I just said MVRP in my earlier posting to
the Rbridge list and in my presentation to the TRILL working group in
Philadelphia. MVRP also appears to me to be technically superior to GVRP
because you can sometimes replace thousands of GVRP frames with one MVRP
frame.

I assume by "advertise" VLANs below you mean propagate through the link
state database. I've got no problem with there being additional methods
to configure VLANs but I think we will need to say how to configure them
with SNMP (even if that is mostly just a pointer to an existing bridge
MIB) and say how they work with 802.1 dynamic VLAN registration.

In a later message you clarified your statement that MVRP was not
mandatory to implement by narrowing that claim to 802.1D bridges. Since
802.1D bridges are VLAN ignorant and do not support VLANs, it is hardly
surprising that they do not mandate implementing dynamic VLAN
registration. But the TRILL WG has decided that Rbridges will support
VLANs and, in most cases, be incrementally deployable into 802.1Q
bridged LANs. As I document in a separate message, as far as I can see,
802.1Q requires the implementation of dynamic VLAN registration.

Donald

-----Original Message-----
From: Dinesh G Dutt [mailto:ddutt at cisco.com] 
Sent: Wednesday, March 19, 2008 8:10 PM
To: Eastlake III Donald-LDE008
Cc: Radia Perlman; Developing a hybrid router/bridge.
Subject: Re: [rbridge] VLAN registration

I'm firmly opposed to having MVRP support a SHOULD or a MUST. We have 
found no customers wanting it so far. I don't see why RBridge spec needs

to say anything more than how VLANs are advertised. How they discover 
what VLANs to advertise is a specific RBridge implementation detail. 
Some may use MVRP, some may use some proprietary protocol (this is not 
the reason for my opposition) and some may use local configuration. MVRP

support is not a MUST or a SHOULD and I don't want RBridge support to be

so either.

Dinesh