Key points one needs to know about MPLS

MPLS(Multiprotocol label switching) is highly emerging network technology which makes use of existing IP technology.MPLS supports traffic engineering which ensures the quality of service and makes best of network bandwidth.
MPLS cloud consists of network nodes enabled with MPLS protocols for signalling and data transfer.
Label distribution protocol(LDP) & Resource reservation protocol(RSRV) are the major protocols used by most of service providers/vendors.MPLS cloud consists of nodes which are categorized as Provider edge(PE),Customer edge(CE) & Provider(P).Label switched paths(LSP) are maintained between the two PE devices.Switching and forwarding decisions are taken based on the label assigned in the node.

Following are the key points which one should know about MPLS:

1. LSPs are maintained between two PEs.
2. LDP protocol is used for normal traffic i.e it doesn't support any protection mechanism.
3. RSVP protocol is used for TE(Traffic engineering) i.e. it supports node protection,link protection and path protection to ensure the quality & reliability of service. 
4. Label is defined for each node; like for this incoming interface use this label and for outgoing interface use this label.
5. Ingress LER(Label edge router) sends the label request to egress node, and the nodes respond with the Label mapping. This way label is exchanged among the nodes.
6. MPLS works for Any Layer2 technology like ATM, Frame relay, Ethernet & EoSDH/EoSONET.
7. MPLS is best for Quality of service & Traffic engineering.
8. All LSRs(Label switched routers) must speak IP routing and MPLS signaling protocols, and provide standards-based interfaces.
9. Major Applications: VPNs & TE
10. MPLS addresses the scalability issues associated with the currently deployed IP-over-ATM overlay model.
11.  MPLS significantly reduces the complexity of network operation.
12. MPLS facilitates the delivery of new routing capabilities that enhance conventional IP routing techniques.
13. MPLS offers a standards-based solution that promotes multivendor interoperability.
14. Overcomes the limitation of ATM-over-IP(Scalability problems)