RE: L2VPN (Re-)charter: Service Convergence

["BALUS Florin" <[e-mail]>]

Shane,
See in-line... 

> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]] 
> On Behalf Of Shane Amante
> Sent: Wednesday, April 02, 2008 7:03 AM
> To: [e-mail]
> Subject: L2VPN (Re-)charter: Service Convergence
> 
> Loa, Florin, Ali,
> 
> ------Loa wrote------
>  > - I'm a bit uncertain about whether there are one or two 
> multi-homing
>  >   scenarios in the text
>  >   -- VPLS using multi-homed CEs
>  >   -- multi-homed VPLS solutions
> 
> See Florin's suggested text below.  I think Florin is 
> suggesting to clarify that we need both, (if I interpret your 
> 2nd bullet correctly).
> 
> 
> ------Florin wrote------
>  > The L2VPN WG scope includes the following:
>  > [..]
>  > 6. Improved service convergence for multi-homed CE's to VPLS PE's.
>  >    Specifically, upon failure of a primary path from a CE 
> to VPLS PE,
>  >    initiate a rapid switch-over to an alternate path.  If required,
>  >    interactions with native service-layer resiliency 
> mechanisms will be
>  >    provided via solutions from other IETF WG's such as PWE3.
>  >
>  > FB> Suggest we modify the text to include also 
> multi-homing between 2
>  > VPLS domains, see below an example of text:
>  > 6. Improved service convergence for multi-homing 
> solutions: CEs to VPLS
>  > PEs or between VPLS domains.
> 
> Can you clarify this further?  Specifically, do you mean the 
> following 
> two cases:
> a)  One CE to two different VPLS PE's in a single AS; and,
> b)  One CE to two different VPLS PE's, each in a different AS?
> 

Not really. What I had in mind was more along the following:
a) CEs multi-homed to different VPLS PEs 
b) a VPLS domain multi-homed to another VPLS domain: e.g. a VPLS mesh in
domain 1 multihomed to a VPLS mesh in domain 2.  
Examples of criteria that may define what a VPLS domain is: geographical
(metro, national, international), administrative different
organizations/providers) etc...

> Also, correct me if I'm wrong, but PWE3 has already covered 
> multi-homing of a MTU-s to two, different PE-rs'es in 
> draft-muley-pwe3-redundancy-02? 
>   Or, is there addt'l work that L2VPN WG needs to take care of 
> specifically for that case?

draft-muley-pwe3-redundancy (adopted as PWE3
draft-ietf-pwe3-redundancy-00.txt) can be definitely applied to optimize
the procedures described in section 10.2 of RFC 4762 (VPLS MTU-s to
PE-rs resiliency). Still I think there is a need to have a discussion
about usage in a VPLS context to ensure interoperability, including an
update on how to reflect the PW transitions in LDP MAC Flush.

Also this sort of resiliency (1 MTU-s to 2 PE-rs, triangle like) might
not be enough for the interconnection of two VPLS mesh domains: i.e. the
MTU-s will be a single point of failure. More like a square
interconnection is required here where 2 VPLS PEs in domain 1 are
connected to 2 VPLS PEs in domain 2.

> 
> 
>  > Specifically, upon failure of a primary
>  > path from a between CEs and VPLS PEs or between VPLS 
> domains, initiate a
>  > rapid switch-over to an alternate path. If required, 
> interactions with
>  > native service-layer resiliency mechanisms will be provided via
>  > solutions from other IETF WG's such as PWE3.
>  > FB>
>  >
>  >
>  > The L2VPN WG currently works on the following tasks:
>  > [..]
>  > - Identify requirements for multi-homing of CE's to VPLS PE's.
>  >   elements.  Based on these requirements, define solutions for
>  >   achieving fast convergence after a switchover to an 
> alternate path,
>  >   for example through optimized MAC flushing within a VPLS domain.
>  >
>  > FB> Suggest changing this one to the following text:
>  > - Identify requirements for different multi-homing 
> solutions: i.e. CEs
>  > to VPLS Pes or between VPLS domains. Based on these 
> requirements, define
>  > solutions for achieving fast convergence after a switchover to an
>  > alternate path, for example through optimized MAC flushing 
> within a VPLS
>  > domain.
>  > FB>
> 
> I have the same question here as I do above.  Once we're on the same 
> page, then I think we can tighten the suggested text a little further.
>

I hope the above answer addressed this one too.

> 
> 
> ------Ali wrote------
>  > v) "6. Improved service convergence for multi-homed CE's 
> to VPLS PE's.
>  >    Specifically, upon failure of a primary path from a CE 
> to VPLS PE,
>  >    initiate a rapid switch-over to an alternate path.  If required,
>  >    interactions with native service-layer resiliency 
> mechanisms will be
>  >    provided via solutions from other IETF WG's such as PWE3."
>  >
>  > AS> We should create another bullet to include 
> multi-homing between two
>  > or more VPLS networks.
> 
> Ali: I think you're asking for the same thing as Florin, (see above). 
> If not, please clarify further.
> 
> Thanks,
> 
> -shane
>