Subject: Re: Draft-kpmpella-ppvpn-vpls-01

From: "Hector Avalos" <[email-masked]>
Date: Wed, 23 Apr 2003 20:08:01 +0200

Ali

If the sp provides 2547bis vpns they already use bgp for signaling. So
if they use directed ldp for vpls they will also end with two signaling
protocols. 

Using bgp for signaling in multipoint vpns simplifies sp work. 

Cheers
Hector
--------------------------
Sent from my Wireless Handheld

-----Original Message-----
From: Ali Sajassi <[email-masked]>
To: [email-masked] <[email-masked]>; Ali Sajassi <[email-masked]>
CC: Andrea Ferrarese <[email-masked]>;
[email-masked] <[email-masked]>
Sent: Wed Apr 23 17:30:28 2003
Subject: Re: Draft-kpmpella-ppvpn-vpls-01

Hi Robert,

That was not the conclusion that I was arriving at. The way I look at it
is 
if a service provider needs to support both type of services (Multipoint

and PtP), then we know that BGP is not suited well for PtP applications;

therefore, the service provider needs to support directed LDP (as
specified 
in PWE3). Now if the service provider insists in using BGP as signaling 
mechanism for Multipoint application (VPLS), then they end up supporting

and maintaining both types of signaling mechanisms in their networks !!

Also I don't like to tie up the signaling to the auto-discovery because 
they are independent. Therefore, a SP who wants to use BGP as 
auto-discovery, can do that and still use LDP as signaling and the SPs
who 
want to use directory-based auto-discovery, can do that with the same
LDP 
signaling.

The argument between BGP and LDP signaling is that the BGP-camp assumes 
that there is nothing else to be distributed to VPLS members except
labels; 
whereas, LDP camp doesn't want to impose such a big constraint as there
are 
PW characteristics (such as QoS, sequencing, OOB OAM) that require 
additional info exchanges. LDP signaling offers a more flexible approach
to 
carry PW specific info and with the state of VPLS and data-plane still 
being evolved, I would like to have a flexible signaling. Besides, as 
mentioned before, you have to use the same signaling for PtP application

anyway.

-Ali

At 09:06 AM 4/23/2003 +0200, Robert Raszuk wrote:
>Hi Ali,
>
>Very valid question ;) ...
>
>Even more valid would be to rephrase it to say: "Do all service
>providers which support the draft-kompella-ppvpn-vpls-xx for VPLS and
>plan to offer some other forms of L2 p2p trasport would have objections
>to run both signalling menthods for setting them up (BGP for VPLS and
>targeted LDP for all other VPWS)" ?
>
>My personal _individual_ opinion is that vendors should support both
>signalling options as it seems quite common that a proper and fine
tuned
>tool for any work produces better results :).
>
>Another spin on this thread is that if Juha's Radius propsal would be
>selected as an auto-discovery option clearly there should be no need to
>mess with BGP at all and signalling could be done with LDP in all
cases.
>But if one selects to use BGP for VPLS autodiscovery adding few more
>bytes there with encoded very clever way of distributing label
>informations especially for VPLS services seems very reasonable.
>
>R.
>
>
> > Ali Sajassi wrote:
> >
> > I'd like to know how many of the service providers who support this
draft,
> > only plan to offer multi-point Ethernet service (VPLS) and do NOT
plan to
> > offer point-to-point Ethernet service?
> >
> > If a service provider plans to offer both types of services, then do
they
> > plan to use BGP for PW signaling of PtP Ethernet service ?
> >
> > Thanks,
> > Ali
> >
> > At 06:15 PM 4/22/2003 +0200, Andrea Ferrarese wrote:
> > >We support draft-kompella-ppvpn-vpls-01
> > >
> > >We found that BGP control plane give scalability and flexibility.
We
> > >like
> > >the possibility to maintain the actual config and VPN
infrastructure
> > >for
> > >both l2 and l3 VPN.
> > >Thank you

---

From: "Jim Guichard" <[email-masked]>
Date: Wed, 23 Apr 2003 14:59:16 -0400

Hector - it is also fair to say that the chances are they are using LDP for
their 2547 service. This means they already have two protocols in operation.
I think it is also fair to say that anyone with experience of running a 2547
service will understand the complexity of controlling route distribution -
extending this to also cover L2VPN service seems to me to be questionable
considering the fact that a point-to-point protocol has already been
deployed. Jim

> >From: Hector Avalos [mailto:[email-masked]]
> >Sent: Wednesday, April 23, 2003 2:08 PM
> >To: [email-masked]; [email-masked]
> >Cc: [email-masked]; [email-masked]

---

From: Eric Rosen <[email-masked]>
Date: Wed, 23 Apr 2003 15:33:59 -0400

Hector> If the sp provides 2547bis vpns they already use bgp for signaling. 

No they don't, as 2547bis does not use any signaling.

---

From: "Vach Kompella" <[email-masked]>
Date: Wed, 23 Apr 2003 12:28:15 -0700

Are you not also using LDP for your tunnel signaling protocol for 2547?

-Vach

> Sent: Wednesday, April 23, 2003 11:08 AM

---

From: Jay Kumarasamy <[email-masked]>
Date: Wed, 23 Apr 2003 13:25:56 -0700

>If the sp provides 2547bis vpns they already use bgp for signaling. So

BGP, only for carrying routes, no signalling.

>if they use directed ldp for vpls they will also end with two signaling

How so ?

If LDP is used for MPLS forwarding, then LDP is
already in the core.

- Jay

---

From: Ali Sajassi <[email-masked]>
Date: Wed, 23 Apr 2003 14:18:38 -0700

>if they use directed ldp for vpls they will also end with two signaling

The point is Martini signaling has already been used/deployed for PtP 
application and the same signaling (without adding any new extensions) can 
be used for VPLS because VPLS uses PtP PWs. In other words, if a SP already 
supports PtP applications, then it can leverage the same signaling for 
VPLS. And the SP can still use BGP for auto-discovery part if they choose so.

You cannot say the same thing with 2547bis because even the same protocol 
is used but different extensions are required for VPLS.

-Ali