Re: MPLS Payload

label allocation is significent only between two routers

FEC simple means destinations prefixes .

egress router assigns labels randomly ...let say he has 10.0.0.0/24 ,
11.00.0.0/24... and allocates 20 and 21 respectively .

via LDP he (R2) sends his mappings to its downstreem peer (R1).
saying if you recieve any packet destined to 10.0.0.0 send me labeled
packet with label 20.

now he has incomming label 20..mapped to 10.0.0.0 .......later he
hears a mapping from his (R3) uptreem peer mapping (next hop) ..let
say again 20 . this completes his binding.

---10.0.0.0 incommng 20 <=SWAPPED WITH => 20 ---

On Sat, Apr 13, 2013 at 10:45 AM, bitje <lj_at_cli.nu> wrote:

> Through L(abel)D(istribution)P(rotocol) which is enabled when you
> issue the "mpls ip" command.
>
> On Sat, Apr 13, 2013 at 01:11:21PM +0530, vishal bhugra wrote:
> >Hello experts
> >
> >I was reading MPLS Fundamental book. In Chapter 2 page 36, they have
> >mentioned that MPLS Label do not have network level identifier. It is the
> >egress router that created label for the FEC and when that label arrives
> at
> >the Egress LSR it knows that this label belongs to which FEC.
> >
> >My question here is packets are classified at the ingress router and they
> >been allocated to a FEC. How do Egress LSR has communicated to Ingress
> >router that which label to choose for which FEC.
> >
> >May be I misunderstood, then what is correct and how Egress router know
> >that what is the payload of MPLS packet.
> >
> >I am not talking about MPLS VPN here, but the simple MPLS.
> >
> >
> >
> >--
> >Thanks&regards
> >
> >Vishal
> >+91 8587900305
> >
> >Best way to predict the future ..... is to create it
> >
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Received on Sat Apr 13 2013 - 10:59:47 ART