Re: CE-based VPLS

[Giles Heron <[e-mail]>]

On Thu, 2003-07-17 at 19:27, Cheng-Yin Lee wrote:
> Vach, Loa,
> 
> The L2VPN charter states
> "The WG is responsible for standardization of the following solutions:
> 1. Virtual Private LAN Service (VPLS)--L2 service that emulates LAN
>   across an IP and an MPLS-enabled IP network, allowing standard
>   Ethernet devices communicate with each other as if they were
>   connected to a common LAN segment.
> ...
> "
> 
> This is the service that CE-based VPLS (where CE is provisioned by
> provider) provides. I believe it does allow standard Ethernet devices to
> communicate with each other as if they were connected to a common LAN
> segment. So I think CE-based VPLS is within the scope of the L2VPN
> charter (unless the charter is changed to explicitly exclude CE-based
> VPLS). 
> 
> I believe the following drafts do not currently allow standard Ethernet
> devices to communicate with each other as if they were connected to a
> common LAN segment:
> http://www.ietf.org/internet-drafts/draft-ietf-ppvpn-vpls-ldp-00.txt
> http://www.ietf.org/internet-drafts/draft-ietf-ppvpn-vpls-bgp-00.txt
> http://www.ietf.org/internet-drafts/draft-radoaca-ppvpn-gvpls-02.txt
> http://www.ietf.org/internet-drafts/draft-shah-ppvpn-ipls-02.txt

On what basis do you make this assertion?

Or is this back to your previous post referencing Tony Li's email about
disconnects between non-DR routers in the case of ISIS or OSPF?

Since this is an error condition (i.e. not something that happens during
normal operation of a VPLS) I would have to disagree with your assertion
if this is indeed what you are referring to.

For what it's worth, my view on the problem of loss of connectivity
between CE routers is that when doing VPLS over MPLS it is preferable to
use LDP to set up the tunnel labels - since I am happier trusting LDP to
give me a full mesh than I am RSVP-TE (partly because there is no risk
of LSP preemption or of failing to find a path matching a set of
constraints, but also because there is no risk of "fat finger" problems
resulting in missing config for an LSP).  This is probably sloppy
reasoning on my part, and I know a few vendors who don't agree with
me...

It is also worth remembering that not all VPLS instances with CE routers
will use IGPs.  Some may use BGP between the CEs, in which case
disconnects are only an issue if there are route servers in the mix.

Giles

> I believe this draft does allow standard Ethernet devices to communicate
> with each other as if they were connected to a common LAN segment:
> http://www.ietf.org/internet-drafts/draft-lee-ppvpn-hybrid-vpls-01.txt
> 
> 
> Thanks
> Cheng-Yin
> 
> 
-- 
=================================================================
Giles Heron    Principal Network Architect    PacketExchange Ltd.
ph: [phone]              "if you build it they will yawn"
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