MPLS

MPLS resolves the same problem as NHRP but in a different way. MPLS is a new concept (as of this writing), and not all of the standards and mechanisms are fully worked out. This chapter covers an overview of the theory.

Normal Packet Switching

Switching an IP packet normally involves the following procedure:

  1. Looking up the destination IP address in a table that might contain several overlapping matches

  2. Choosing the matching destination network with the longest prefix length

  3. Finding the MAC header for the next hop and copying it onto the front of the packet

The deployment of ATM and Frame Relay brought a new idea to the forefront in switching packets: switching based on a short label that can be swapped hop by hop as a packet moves toward ...

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