RE: Extensions to LDP Signaling for PBB-VPLS -

["David Allan" <dallan at nortel.com>]

Understood,

...but I don't see a difference between administering MH-IDs and
administering B-MACs, 1:1 cardinality for any incremental administration
...and such state needs to reside somewhere....you simply now have more
classes of it...

IMO if a dual homed network is given a PIP on each of the PEs it is
homed upon with the slight abuse of having a common B-MAC address, I
believe no changes to existing control plane procedures are required,
and the subtending Ethernet can then select the active port (via MC-LAG,
STP or whatever procedures) without requiring any VPLS procedures or
control plane interworking to speak of. I will see more B-MAC addresses
than I would see otherwise,  but IMO this is only really parsitic if the
dual homed customer network is a single C-MAC (router). 

As for actual failure scenario, after the PIP B-MAC is withdrawn, there
will simply be a few flooded frames at the B-MAC layer until the new
path to the customer network is learned via the alternate PIP, the
customer network will not experience a lot of flooding of C-MAC frames
as the network convergence, in effect the fact there was a failure in
the network will not manifest itself in a lot of customer layer flooding
of frames...ergo, silently recovered ;-)

I like it...

Cheers
Dave

-----Original Message-----
From: BALUS Florin [mailto:Florin.Balus at alcatel-lucent.com] 
Sent: Thursday, July 30, 2009 11:04 AM
To: Allan, David (CAR:NS00); l2vpn at ietf.org
Subject: RE: Extensions to LDP Signaling for PBB-VPLS - 

Hi Dave,
As discussed after the session, we are proposing a generic solution that
does not depend on any special, locally configured, BMAC assignment
scheme. 
Florin

> -----Original Message-----
> From: David Allan [mailto:dallan at nortel.com]
> Sent: Thursday, July 30, 2009 12:49 AM
> To: BALUS Florin; l2vpn at ietf.org
> Subject: Extensions to LDP Signaling for PBB-VPLS -
> 
> Hi Florin:
> 
> I understand the problem this proposes to solve, but I believe there
is
> a simpler way. If you assign a B-MAC to a multihomed customer site
then
> you never need to invalidate C-MAC to B-MAC bindings and a MAC 
> invalidate message for the B-MAC is sufficient to ensure no black 
> holing when an AC goes down, normal flooding and learning permitting 
> remote PEs to learn which PE the customer site is reachable via. This 
> provides
for
> the possibility of localizing the blocked/unblocked decision for the 
> ACs (which IMO needs to be coordinated between the MH PEs in order to 
> be robustly loop free) as knowledge of the multi-homing does not need 
> to be propagated into the network.
> 
> WDYT?
> Dave