1. MPLS Concepts Introducing Basic MPLS Concepts

2. Outline Overview What Are the Foundations of Traditional IP Routing? Basic MPLS Features Benefits of MPLS What Are the MPLS Architecture Components? What Are LSRs? Summary

3. Foundations of Traditional IP Routing Routing protocols are used to distribute Layer 3 routing information. Forwarding decision is made based on: –Packet header –Local routing table Routing lookups are independently performed at every hop.

4. Traditional IP Routing Every router may need full Internet routing information. Destination-based routing lookup is needed on every hop.

5. Basic MPLS Features MPLS leverages both IP routing and CEF switching. MPLS is a forwarding mechanism in which packets are forwarded based on labels. MPLS was designed to support multiple Layer 3 protocols Typically, MPLS labels correspond to destination networks (equivalent to traditional IP forwarding).

6. Benefits of MPLS MPLS supports multiple applications including: –Unicast and multicast IP routing –VPN –TE –QoS –AToM MPLS decreases forwarding overhead on core routers. MPLS can support forwarding of non-IP protocols.

7. MPLS Architecture: Control Plane

8. MPLS Architecture: Data Plane

9. MPLS Devices: LSRs The LSR forwards labeled packets in the MPLS domain. The edge LSR forwards labeled packets in the MPLS domain, and it forwards IP packets into and out of the MPLS domain.

10. Label Switch Routers: Architecture of LSRs

11. LSR Architecture Example MPLS router functionality is divided into two major parts: the control plane and the data plane.

12. LSRs: Architecture of Edge LSRs

13. Basic MPLS Example MPLS core routers swap labels and forward packets based on simple label lookups. MPLS edge routers also perform a routing table lookup, and add or remove labels.

14. Summary Traditional IP routing forwards packets based on the destination address. MPLS forwards packets based on labels. MPLS supports multiple applications. MPLS has two major architectural components: –Control plane (exchanges routing information, exchanges labels) –Data plane (forwards packets) LSRs implement label exchange protocols and primarily forward packets based on labels. The role of Edge LSRs is primarily to forward packets into and out of the MPLS domain.