Hi,
what you are asking about is too much of information to be described in a slite reply or definition, but here are Very BASIC and Simple information about MPLS:
MPLS: is a multi-protocol label Switching defined as Control Plane Technology to Optimize Network behaviour Of mapping Layer-3 Data Flow to Layer-2 traffic between Network Nodes.
MPLS Label Format is consist Of 32 Bit , 20 bit is the Label (SHIM) + 3 bit is Exprimental bit 1 bit + 6 bits for TTL
The TAG & LDP describes the Control Plane in an MPLS, LDP is IETF standard and TDP is Cisco Proprietary, an interface must be enabled for any of those to start forward and recognize MPLS packet, However , Still there is RSVP and they are differ.
An MPLS Network based differ from an IP-Network base interms of each protocol behaviour for finding the best path to reach specific destination , Decisions in MPLS based On Label since all MPLS routers builts LIB (Label information base) On top of the routing protocol used. Unlike Normal Routing lookup, However MPLS built all LIB/LFIB based On the routing protocol.
VRF: Its Virtual routing forwarding, Multiple VRFs is like Multiple logical routers , each with its own routing table.
One Of the Main biggest advantage Of MPLS is MPLS-VPN, MPLS-VPN allows VPN connectivities over an MPLS infrastructure, By carrying the VRFs through an MP-BGP through an extended communities.
(MPLS - VPN label) contains extra added label for each specific VPN + the LDP label, so that when the original VRF routes carried is forwarded to the correst customer part of the VPN and to the correct customer interface.
Finally, The P , PE , CE defines , Provider routers (Performs Only label Swapping) , PE provider edge router (the ingress and egress nodes for each Label Switch path) , and Cutomer Edge router attached to ur PE and the type of service differ based on Customer requirment.
I would suggest u go through some Documents to more understand MPLS.
Regards,
Mohamed Sobair
