The MPLS-OPS Archive

[Roger Clark Williams <rogerw@nordlink.com>]

Anitha, on Cisco router platforms CEF is necessary for running MPLS. This
cached table stores the chosen related label pairs and the related
outbound interface.

I am not sure of the detail you want in your second question. In concept,
a frame arrives at an inbound router interface. The ethertype in the
Layer 2 frame header identifies the frame as MPLS so the router expects a
label to follow the Layer 2 header. It reads the label and, based on that
label, does a lookup in the cached table. The lookup supplies the
outgoing label related to the incoming label, and also supplies which
interface the frame should be sent out. The old label is stripped from
the frame and the new label replaces the old top label (as there can be
more than one label in a label stack). The frame is sent out out the
specified outbound interface.

I hope this is what you wanted.

Roger Williams

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From: "Sudha" <sudha.r@ddsl.net>
To: "Doug Legge" <Doug.Legge@BerkeleyGroup.co.uk>,
        "'anitha'" <netgurujis@yahoo.com>
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Subject: Re: [MPLS-OPS]: New to MPLS
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Hi Doug,
    Thanx for the URL..It was pretty informative.
I have one query..
To run MPLS, is that CEF is necessary??
Also can anyone of you explain how exactly the label swapping occurs when a packet moves from A to B on an MPLS enabled network?
 
Thanx in advance.
 
Regards.
anitha.
 
 
 
 

----- Original Message -----

From: Doug Legge

To: 'anitha'

Cc: 'mpls-ops@mplsrc.com'

Sent: Friday, January 23, 2004 5:29 PM

Subject: RE: [MPLS-OPS]: New to MPLS

Anitha,

 

Try the excellent MPLS Resource Center at:

http://www.mplsrc.com/faq1.shtml#MPLS%20History

 

Doug

-----Original Message-----

From: anitha [mailto:netgurujis@yahoo.com]

Sent: 23 January 2004 11:50

To: mpls-ops@mplsrc.com

Subject: [MPLS-OPS]: New to MPLS

Hi MPLS techies..

I have joined this group today..Can any one of you pls tell me in simple and technical terms " what MPLS is??" I read many MPLS Docs...but need a crisp answer from you people. what is a label and LDP? can we compare this with a tag and VTP wrt switches? How exactly MPLS works?

 

Thanks is advance..

anitha.

 

 

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