[rbridge] VLAN registration

[Dinesh G Dutt]

Donald,

First off, if I used the word .1D bridges,  I really meant .1Q bridges. 
IEEE does  NOT mandate MVRP or MMRP to be implemented in 802.1Q bridges. 
Dynamic VLAN registration is not mandated in the 802.1Q 2005 standard. 
So, TRILL spec should not either. Further, I know of no customer using 
these protocols in their networks and I work closely with a lot of 
customers in the field, from small networks to F500 customers.

Next, are we going to specify what an Rbridge does for every single IEEE 
protocol ? I don't think so. If we get into that game, we're in deep 
trouble. I'm fine if someone wants to write an informational draft that 
talks about how an RBridge should correctly implement various IEEE 
protocols. I, for one, don't think it is valuable in the base protocol 
spec, has the danger of being out of date and duplicating information. 
I'd like to draw a clean demarcation of Rbridge functionality from IEEE 
bridge functionality. We don't specify how VLANs work in this draft. 
They're specified in IEEE and folks follow those documents for 
understanding and implementing VLAN functionality.

Rbridges are forward looking. They fix what is broken and is in urgent 
demand, by keeping it simple and not complicating the base protocol with 
unnecessary functionality. They don't get to be forward looking by 
mandating what is not required in the field, that standards bodies that 
define those standards don't mandate either.

If we had broken statements about handling dynamic VLAN registration in 
the draft, let's take it out completely, not fix it. I must've missed 
seeing that section or you'd have heard me holler a lot sooner.

Dinesh
Eastlake III Donald-LDE008 wrote:
> 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
>
>   

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