The MPLS WG Archive

[Bora Akyol <akyol@pluris.com>]

You are right,

I did not think about the ATM case (I should have been more specific, 
apologies extended), but I do not understand the difference between having 
MPLS LSP over POS vs MPLS LSP over ATM as long as either end of the LSP 
understands IP; i.e. what is the significance to the IP router of having 
MPLS over ATM vs MPLS over POS LSP? Or is there an ATM switch at one end of 
the LSP that does not have a routing protocol running and uses a 
lookup/classification table for IP to LSP mapping (ouch).


Thanks for catch.

Bora



At 06:47 PM 4/26/00 +1000, Jeremy Lawrence wrote:
>At 17:39 04/25/2000 -0700, Bora Akyol wrote:
> >I presume you are not familiar with how MPLS is actually used in 
> providers networks.
>
>I presume you are not familiar with how MPLS is actually used in providers'
>ATM networks. :)
>
> >FEC to LSP binding is almost historical now.
>
>That's arguably true in router-based networks, because of the
>predominance of TE as an application of MPLS in those networks.
>However, FEC to LSP binding is very much alive in ATM MPLS
>networks. Also, at least one MPLS-based VPN scheme relies on
>hop-by-hop routed MPLS (which may, in turn, be over-ridden by
>TE) in network cores of any type.
>
>Regards,
>
>Jeremy Larence
>
>
>
>
> >At 10:55 AM 4/25/00 +0530, Manish R. Shah. wrote:
> >
> >>Hi !!!
> >>
> >>Once the LSP's are created, the ingress router looks for the matching 
> FEC, and attaches
> >>a label corresponding to that FEC on to the data packet. Further 
> forwarding is done using
> >>the label switching.
> >>
> >>In an MPLS domain the LDP has already taken care of mapping
> >>FEC's with the incoming and outgoing Labels and efficient distribution 
> of Labels.
> >>
> >>Look at the following draft for furthur 
> details.  draft-ietf-mpls-ldp-06.txt
> >>
> >>Cheers !!!
> >>
> >>Manish R. Shah.
> >>Senior Software Engineer,
> >>Future Software Pvt Ltd.
> >>480-481, Anna Salai, Nandanam
> >>Chennai 600035.
> >>Phone: +91-(44)-433-0550 Xten 294.
> >>
> >>
> >>-----Original Message-----
> >>From:   Neetu Gupta [SMTP:neetug@daewoo.dti.daewoo.co.kr]
> >>Sent:   Tuesday, April 25, 2000 10:28 AM
> >>To:     mpls@uu.net
> >>Subject:        Finding the Egress Point in the MPSL Domain for the 
> specific Destination
> >>
> >>Hello,
> >>     Suppose the LSPs are created among the Edge Routers in the MPLS
> >>Domain with specific class of services. Now the data packet comes at the
> >>Ingress LER, the IP Header contains the Destination Address and TOS
> >>byte.
> >>
> >>Since there are labels to Egress Router, to which Egress LER the data
> >>packet will be forwarded that will route to the Destination?
> >>
> >>I've heard of the draft that specifies how to treat LSP tunnel end node
> >>like LSP egress edge as next node for route calculations.
> >>Please give some reference.
> >>Neetu
> >
> >
> >
> >