MPLS FEC and LIB

Hello experts

While reading MPLS basics, I have a query :-

FEC says providing the same behavior to same kind of packet that is
allocating the same next hop, same egress interface.

AS book says - "In MPLS, the assignment of a particular packet to a
particular FEC is done just once, as the packet enters the network. The FEC
to which the packet is assigned is encoded as a short fixed length value
known as a "label". "

That mean classifying the packets and assigning the labels as per the
classification.

and for LIB book says - " The LIB functions in the control plane and is
used by the label distribution protocol where IP destination prefixes in
the routing table are mapped to next-hop labels that are received from
downstream neighbors, as well as local labels generated by the label
distribution protocol."

I am confused - FEC says classifying the packet and assigning the label and
LIB says destination prefixes are mapped to labels.

*If Destination prefixes need to mapped to labels then why do we need to
classify the packets and why do we need FEC ?*

*
*

*I know that I am missing something because books area already reviewed by
experts.*

Thanks&regards
Vishal
+91 8587900305

Best way to predict the future ..... is to create it

Blogs and organic groups at http://www.ccie.net
Received on Wed Jan 16 2013 - 16:27:01 ART