Subject: Query Regarding BGP-MPLS-VPLS Restart

From: "Abhay D.S" <[email-masked]>
Date: Mon, 18 Dec 2006 12:15:18 +0800

hi group,

How does a Route Reflector with VPLS advertisement capability
behave during a graceful re-start.

What happens to VPLS allocations when RR undergoes re-start ?.

Rgds,
Abhay

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From: Kireeti Kompella <[email-masked]>
Date: Mon, 18 Dec 2006 21:28:09 -0800 (PST)

> What happens to VPLS allocations when RR undergoes re-start ?.

To what VPLS allocations are you referring?

> Abhay

Kireeti.
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From: "Abhay D.S" <[email-masked]>
Date: Tue, 19 Dec 2006 13:34:08 +0800

hi kireeti,
In the mpls-bgp-restart-draft
4.3. Case 3

   The following applies when the LSR does not set BGP next hop to self.

   In this case the LSR, when advertising its best route for a
   particular NLRI just uses the label that was received with that
   route. And if the route was received with no label, the LSR
   advertises the route with no label as well. Either way, the LSR does
   not allocate a label for that route.

I think this condition the LSR is just an RR ?. Im not sure my assumption
is correct .

Thank you,
Rgds,
Abhay

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From: Kireeti Kompella <[email-masked]>
Date: Mon, 18 Dec 2006 22:03:04 -0800 (PST)

> I think this condition the LSR is just an RR ?. Im not sure my assumption

An RR for VPLS would not set the BGP nexthop to self, so it would 
satisfy this condition.  However, such an RR would not make any VPLS 
"allocations", if by that you mean labels.  The RR (as per the quoted 
draft) must first re-acquire all the VPLS updates (including label 
blocks) from its neighbors.  Once it does that successfully, the RR 
can then do path selection and advertise VPLS NLRIs to its neighbors 
*with the received label blocks*.  The RR does not allocate new label 
blocks.

HTH.

Kireeti.
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From: "Abhay D.S" <[email-masked]>
Date: Tue, 19 Dec 2006 14:06:04 +0800

hi kireeti,
Thanks, yes I agree RR does not allocate labels.
Probably the draft could be modified to say that RR is the case.
Rgds,
Abhay

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From: Kireeti Kompella <[email-masked]>
Date: Mon, 18 Dec 2006 22:25:31 -0800 (PST)

> Probably the draft could be modified to say that RR is the case.

Not really.  There are many reasons why a BGP-speaking LSR may not set 
BGP nexthop to self.  This draft is not for VPLS alone, but any NLRI 
with labels.

On the other hand, the draft should apply to BGP VPLS.  If you find it 
does not, please let the authors know (or me, and I'll forward it to 
the authors).

Thanks!

>> An RR for VPLS would not set the BGP nexthop to self, so it would satisfy 
>> this condition.  However, such an RR would not make any VPLS "allocations", 
>> if by that you mean labels.  The RR (as per the quoted draft) must first 
>> re-acquire all the VPLS updates (including label blocks) from its 
>> neighbors.  Once it does that successfully, the RR can then do path 
>> selection and advertise VPLS NLRIs to its neighbors *with the received 
>> label blocks*.  The RR does not allocate new label blocks.
>> 
>> HTH.
>> 
>>> Thank you,
>>> Rgds,
>>> Abhay
>>> 
>>> Kireeti Kompella wrote:

Kireeti.
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