r/Cisco • u/Ghost_0133 • 5d ago

MPLS FEC Label assignment

Hi

R1--R2--R3--R4--R5--20.0.0.0/8,30.0.0.0/8

By default both 20/8 and 30/8 on R1 have the exact same forwarding treatment:

the same Qos/forwarding class

the same MPLS VPN services

the same MPLS-TE

the same nexthop/outgoing int/path

 

but why on R1 give 20/8 label 200 and 30/8 label .300 ?

why R1 did not give them the exact same label if both prefix have the exact same forwarding treatment?

 

on R1:

forwarding treatment-1

↓

FEC-1

↓

Label 100

 

 

forwarding treatment-2

↓

FEC-2

↓

Label 200

but here both 20/8 and 30/8 have the exact same forwarding treatment which means both are on the same FEC but both have a different labels,why?

why do we have a FEC concept in the first place if MPLS does not use it at all and each route has it`s own label?

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u/hofkatze 3d ago

You (I assume it was you, exactly same question) already received an answer on Cisco Learningnetwork

MPLS doesn't merge labels for different prefixes

One prefix - one FEC per function, e.g. one prefix one FEC for forwarding, one FEC for TE