The MPLS WG Archive

["Greg Mirsky" <gmirsky@turinnetworks.com>]

Title: RE: [mpls] RE: Comments on draft-leroux-mpls-p2mp-te-bypass-00.txt

Dear Jean-Lois,
I think that there's no question that using p2p bypass tunnels as node protection for a branch LSR doesn't scale well. But how well will scale p2mp bypass tunnel for the node protection? I understand Kireeti's questions as "Isn't Link Protection is good enough while Node Protection is just marginally better"?

Regards,
Greg


-----Original Message-----
From: LE ROUX Jean-Louis RD-CORE-LAN [mailto:jeanlouis.leroux@orange-ftgroup.com]
Sent: Thu 11/9/2006 10:12 AM
To: HEMIGE Venu; Kireeti Kompella
Cc: mpls@ietf.org
Subject: RE: [mpls] RE: Comments on draft-leroux-mpls-p2mp-te-bypass-00.txt

Hi Venu

Think about the protection of a branch node with N downstream LSRs.
If you rely on P2P Bypass tunnels, you end up with N times the traffic on shared bypass links during failure...
I can show you operational network topologies where N = 50, and you would end up with 50 times the traffic on shared links. For the sake of illustration, to protect a 2G TV traffic, you would need 100G capacity to backup the traffic! no comments...

The situation is not the same with link protection, as you can rely on a single P2P Bypass, and there is no traffic replication at all.

Best Regards,

JL

> -----Message d'origine-----
> De : HEMIGE Venu [mailto:Venu.Hemige@alcatel.com]
> Envoyé : jeudi 9 novembre 2006 17:57
> À : Kireeti Kompella; LE ROUX Jean-Louis RD-CORE-LAN
> Cc : mpls@ietf.org
> Objet : RE: [mpls] RE: Comments on
> draft-leroux-mpls-p2mp-te-bypass-00.txt
>
>
> Hi Jean-Louis,
>
> I agree with Kireeti that node protection is several degrees
> more complex, definitely in the case of P2MP LSPs. However, I
> am not so sure of the efficiency of even link protection for
> P2MP LSP traffic. The bypass tunnel for a protected link may
> be established over another link or set of links behind which
> there are leaves of the P2MP LSP. So when the protected link
> fails, there would be two copies of the traffic forwarded
> over such links. Isn't that also a concern very similar to
> what you are trying to solve in this draft for node protection?
>
> Regards,
> -Venu
>
> 
>
> > -----Original Message-----
> > From: Kireeti Kompella [mailto:kireeti@juniper.net]
> > Sent: Wednesday, November 08, 2006 11:56 AM
> > To: LE ROUX Jean-Louis RD-CORE-LAN
> > Cc: mpls@ietf.org
> > Subject: Re: [mpls] RE: Comments on
> > draft-leroux-mpls-p2mp-te-bypass-00.txt
> >
> > Hi Jean-Louis,
> >
> > To re-iterate my comment in the WG, in general, node protection,
> > whether for p2p or p2mp LSPs, is an order of magnitude less
> scalable
> > than link protection.
> >
> > I think we should step back at this point, and request SPs
> and others
> > deploying MPLS networks to share with the WG: frequencies of link
> > failures, node software failures (node recovers), node failures
> > (requires manual intervention), and battery explosions, to
> give us a
> > sense of the importance of continuing the work on node protection.
> >
> > I realize that some of these figures may be sensitive, but even
> > normalized numbers may be useful.
> >
> > Kireeti.
> > -------
> >
> > _______________________________________________
> > mpls mailing list
> > mpls@lists.ietf.org
> > https://www1.ietf.org/mailman/listinfo/mpls
> >
>

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