1. A Study of MPLS Department of Computing Science & Engineering DE MONTFORT UNIVERSITY, LEICESTER, U.K. By PARMINDER SINGH KANG Email: pkang@dmu.ac.ukpkang@dmu.ac.uk Home: www.cse.dmu.ac.uk/~pkang

2. Why MPLS? Interest. New and Different concept. MPLS merges the connection oriented and packet switching approach. Overlays the layer of intelligence over existing IP network. Different implementation approaches.

3. Introduction Introduction to Networks Technical Description MPLS: The Basic Concept MPLS: The Data Plane MPLS: The Control Plane Implementation LDP Conclusion and Future Work

4. Introduction to Networks What is a Network? Broadcasting and Switching. Connection Oriented Packet Switching. Operation  Call Setup  Data Transfer  Call Termination

5. Traditional Approach Connectionless mechanism. IP address based Forwarding. Routing Decision is based upon routing tables. Main routing protocols are: RIP, IGRP, OSPF, IS-IS and BGP. Application Transport Internet Data Link Internet Data Link Internet Data Link Application Transport Internet Data Link Ethernet Core Network

6. packets are routed independently to the destination even if they are from the same source. Consider two Paths: Path1: node1-router1-router2-router4-node2 Path2: node1-router1-router3-router4-node2 Router 1 Route r 2 Route r 3 Route r 4 Node 1 Node 2 3 2 1 3 1 1 3 2 2 3 1 2

7. Major Drawbacks: Difficult to deliver QoS in multi service network. There is no relation between packet and forwarding path opted. Routing Bottlenecks. Inefficient utilization of network resources. Solution? MPLS

8. MPLS: Connection Oriented Packet Switching MPLS: Multiprotocol Label Switching. Merges the concept of Packet Switched networks and Connection oriented approach. Implemented as an individual layer between IP layer and DLL layer. Application Transport Internet Data Link MPLS Data Link MPLS Data Link Ethernet Core Network MPLS Application Transport Internet Data Link MPLS

9. Operation is divided into two planes: Control plane and Data Plane. Forwarding is based upon label switching instead of long IP address match. Label Selection and Distribution Protocol LIB Data plane Control plane IP Routing Protocol IP Routing Table Label Forwarding table DLL MPLS IP Higher Layer Protocols 32 bits 20 3 1 8 bits Label QoS S TTL

10. Link 1Link 2 Link 3 LER1 LS R2 LER2 MPLS Domain 120.10.4.1 100.101.4.11 IP network Destination address Source address FEC = 3 Interface = 1 Label = 40 Interface = 3 Label = 10 Interface = 2 Label = 14 LS R1 RouterIncoming LabelOutgoing LabelIncoming interfaceOutgoing Interface LER1N/A40101 LSR1401013 LSR2101432 LER214IP based Forwarding 2

11. Advantages of MPLS Defines relation between stream and LSP. Fast Switching. Effective network resource utilization. Easy to implement VPN and QoS delivery. Can interoperate with other major technologies; FR and ATM. Connectionless operation is still available.

12. LDP LDP: Label Distribution Protocol LDP plays vital role in data transfer. LDP is divided into two major categories:  Explicit: LDP Hop-by-Hop and LDP-CR.  Extension to existing protocols: RSVP- TE, MPLS-BGP. Four message Types: Notification, Discovery, Session and Advertisement. Working Concept of TLV.

13. Working LER1 LSR1 LER2 LSR 2 Incoming stream S, FEC F LABEL_REQUEST LABEL MAPPING Data Flow  Discovery  Session establishment.  Label binding.  Data Transfer.

14. Upstream LSR Downstream LSR UDP Hello TCP Connection Establishment LDP Initializations LDP Label Request LDP Label Mapping Data Transfer Time

15. 0 Notification (0x0001) Length 16 bits Message ID Mandatory Parameters Optional Parameters Concept of TLV  Unique message structure.  Type, Length and Value.

16. Implementation Topology Used Ingress LER Egress LER LSR Client MPLS Domain MPLS_ Monitor Assumptions: Communication is Unidirectional only. Single LSP. Only one MPLS domain exists. Each router has only two interfaces. This model uses static routing tables.

17. Conclusion and Future Work Conclusion. Future Work: Multicasting in MPLS. Solution for Data plane and Control plane failure. One possible approach is OAM. LDP Security. Lack of outgoing label. Loop prevention plays a vital role in effective operation. Finally, overlaying TE capabilities on existing structure.

18. Thanks….. Questions…….