Hi,
Thats a big question to ask! However, the control plane of MPLS is complex as several protocols come into play. Howvere the protocol responsible for label distribution is called LDP, which binds an IP prefix to a label.
The forwarding or data plane is simply the act of forwarding a packet ased upon the incoming label to an egress interface.
If you would like more details please refer to or go to www.google.com and type in MPLS at the search line.
HTH - stevep@cisco.com
