Subject: CE-based VPLS

From: "Cheng-Yin Lee" <[email-masked]>
Date: Thu, 17 Jul 2003 15:27:37 -0400

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

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

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From: Kireeti Kompella <[email-masked]>
Date: Sun, 20 Jul 2003 16:38:04 -0700 (PDT)

Hi Cheng-Lin,

On Thu, 17 Jul 2003, Cheng-Yin Lee wrote:

> provider) provides.

It would be interesting (but ultimately irrelevant) to understand how
you made the leap from "service that emulates LAN" to "CE-based VPLS
... where CE is provisioned by provider".  The charter does not say who
provisions the VPLS, although since L2VPN emerged from PPVPN, it seems
logical that the provider provisions it.  Furthermore, the charter
doesn't mention "CE-based".

If by "CE", you mean (as in rfc2547bis) a device owned, operated and
managed by the customer, then "CE provisioned by the provider" is an
oxymoron.  If you mean something else, it would be useful to define it;
and furthermore, to read the decoupled VPLS and the H-VPLS drafts.

> So I think CE-based VPLS is within the scope of the L2VPN

The parenthetical statement is not a bad idea.  Chairs?  ADs?

> http://www.ietf.org/internet-drafts/draft-shah-ppvpn-ipls-02.txt

There is an existence proof that most (if not all) of the above _do_
in fact allow standard Ethernet devices to communicate with each other
as if they were on a LAN.  So, your belief does not jive with reality.
Step into any number of vendor or provider labs for proof.

If there are corner cases where the "VPLS" in the above drafts fails
to emulate a LAN perfectly, please communicate that to the group.
This would be productive, and help the group understand whether the
failure was systemic or the artifact of particular implementations,
and thus guide further standards development.

Kireeti.

---

From: Loa Andersson <[email-masked]>
Date: Mon, 21 Jul 2003 12:38:24 +0200

WG, Kireeti and Cheng-Yin,

Speaking as chair:

It is the opinion of the wg chairs and the ADs that the CE-based
is out of charter.

Speaking as a "terminology police":

CE is not a piece of equipment, it is the functionality needed to handle
the customer side of the vpls (or vpn in genral). Nor is PE a piece of
equipment, it is the functionality needed to handle the provider
side of the vpls (or vpn in general). It is conceivable that the CE and
PE could be allocated to the same box, or to any number of boxes. Don't
ask me why you would like to do that.

/Loa

-- 
/Loa

mobile + 46 739 81 21 64
email: [email-masked]

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From: Giles Heron <[email-masked]>
Date: 18 Jul 2003 00:30:13 +0000

> 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

-- 
=================================================================
Giles Heron    Principal Network Architect    PacketExchange Ltd.
ph: +44 7880 506185              "if you build it they will yawn"
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