The MPLS WG Archive

[Shahram Davari <Shahram_Davari@pmc-sierra.com>]

Vijay,

> -----Original Message-----
> From: Vijay Bollapragada [mailto:vbollapr@cisco.com]
> Sent: Friday, May 31, 2002 2:06 PM
> To: Shahram Davari
> Cc: 'mpls@uu.net'; 'ppvpn@ppvpn.francetelecom.com'
> Subject: Re: Basic LDP Question
> 
> 
> In the 2547 case, typically u have 2 labels, the vpn_label 
> (bottom label)
> and the top label is the label to get the packet to the far 
> end PE, Now,
> LDP is used for this top label.
> 
> I think u are questioning why use LDP for this bottom_label 
> and why not
> simply encapsulate the MPLS packet in IP to get the packet to 
> the next_hop
> PE. If this is your Q, You are absolutely correct and this is what the
> following draft talks about
> 
> http://search.ietf.org/internet-drafts/draft-ietf-ppvpn-gre-ip
> -2547-01.txt
> 
> IMHO, this is certainly do-able but MPLS in the core give us 
> the ability
> to do things like Traffic Enginnering

But LDP does not give you the TE ability. So why use LDP?

-Shahram

 which are quite a challenge over
> pure IP.
> 
> Thanks,
> Vijay
> 
> 
> 
> On Fri, 31 May 2002, Shahram Davari wrote:
> 
> > Hi,
> > 
> > What problem a mp2p LDP-based MPLS network is trying to 
> solve (like the one used in RFC2547) that can't be done with 
> pure IP forwarding?
> > 
> > Note: Don't tell me fast forwarding, because we can do fast 
> IP lookup as well.
> > 
> > Yours,
> > Shahram
> > 
> > 
>