1. TM8106Optical Networking Multi-Protocol Label Switching-Transport Profile (MPLS-TP) By Ameen Chilwan Syllabus: [1] MPLS Transport Profile (MPLS-TP): A Set of Enhancements to the Rich MPLS Toolkit, Juniper Networks, Whitepaper, 2011. [2] Dieter Beller, Rolf Sperber, MPLS-TP – The New Technology for Packet Transport Networks, 2nd DFN Forum, 2009.

2. Outline • Transport Networks • MPLS-TP Basics • Standardization History • MPLS-TP Components • OAM • Control Plane • Resiliency • Synchronization • Physical Infrastructure Support • Deployment Options • Misconceptions about MPLS-TP • Conclusion TM8106 Optical Networking - MPLS-TP

3. Transport Networks • Goal of transport network • Requirements TM8106 Optical Networking - MPLS-TP

4. Packet-based Transport Network • MPLS has been serving as one for almost a decade • Connection-oriented and Packet-based • Designed to carry L3 IP Traffic • Establishes IP traffic paths • Associates these paths with arbitrarily assigned labels • GMPLS extends MPLS • Label switching for • TDM (SONET/SDH) • Wavelength (λ) • Spatial switching (incoming ports to outgoing ports) TM8106 Optical Networking - MPLS-TP

5. MPLS-TP Emergence • Lacks some features of SDH-like networks • Operation, Admin and Management (OAM) • Resiliency • Scalable operations • High availability • Performance monitoring • Multi-domain support • IETF and ITU-T joined forces to enhance MPLS • MPLS-TP TM8106 Optical Networking - MPLS-TP

6. MPLS-TP Background • Drivers for MPLS-TP • Rise in demand for service sophistication • Bandwidth-hungry services • Pressure to reduce operational cost (OPEX) • Maximize the value per bit • Lead to a technology that is almost SDH-like • Carrier-grade • Packet-switched • With OAM features TM8106 Optical Networking - MPLS-TP

7. MPLS-TP Overview • Takes a subset of MPLS/GMPLS • Enhance with some functionalities • Network Management (e.g. FCAPS) • Dynamic provisioning of transport paths via control plane • Provide restoration functions • E2E path provisioning across networks/domains • Characteristics • Connection oriented • Client and physical layer agnostic • OAM similar to SDH-like networks • Protection schemes • Network provisioning via centralized NMS • GMPLS Control plane applicable TM8106 Optical Networking - MPLS-TP

8. Standardization History • ITU-T will define requirements • IETF will work on protocol extensions TM8106 Optical Networking - MPLS-TP

9. MPLS-TP Components TM8106 Optical Networking - MPLS-TP

10. Operation, Admin and Management • Dedicated OAM packet • interspersed into the associated user traffic flows • Created and processed by maintenance end-points • Intermediate points can also process them & collect data • OAM Tools TM8106 Optical Networking - MPLS-TP

11. OAM Functions and Tools • Functions • Fault Detection (e.g. connectivity check) • Fault Localization (e.g. loopback, lock) • Performance Monitoring (e.g. delay, loss) • Tools (Existing MPLS tools extended) • Bidirectional Forwarding Detection (BFD) • LSP Ping • LSP Trace TM8106 Optical Networking - MPLS-TP

12. OAM Enhancements TM8106 Optical Networking - MPLS-TP

13. Associated Channel (ACh) • MPLS-TP shall work without IP functionality • MPLS uses Ach for framing, forwarding and encapsulation • Enhanced by GACh and GACh Label (GAL) • Support in-band control channels • GACh • Ensure congruency between OAM packets and data path • Indicates tagged packet must be processed by special function • Not suitable for static provisioning • Because negotiated when pseudowire was setup • Solved using GAL (reserved value of 13) • Enables easy extraction at end- and mid-point nodes TM8106 Optical Networking - MPLS-TP

14. Control Plane (Static and Dynamic) • Responsible for setup of LSP • MPLS has mature and dynamic control plane • OSPF-TE, IS-IS-TE, RSVP-TE and BGP • Current transport networks have static control plane • using NMS • MPLS-TP • Can have both static or dynamic • Dynamic has advantages like: • Scaling • Advanced protection functions (e.g. LSP tail-end protection) • Restoration • Distributed control plane • Signaling, routing and TE • Decoupled from data plane TM8106 Optical Networking - MPLS-TP

15. MPLS-TP Control Plane (contd…) TM8106 Optical Networking - MPLS-TP

16. Resiliency • Mechanisms in MPLS • LSP fast reroute • Pseudowire redundancy • Path protection • Enhancements in MPLS-TP • OAM-triggered protection • Optimizing protection in ring topologies • Circuit networks are interconnected rings • Fast reroute works but inefficient • Wrapping and steering implemented in MPLS-TP TM8106 Optical Networking - MPLS-TP

17. Synchronization • Approaches • An overlay synchronization network • Requires parallel network • Distributed reference clock • Reference clock at least at the edges • Forwarding of clock information across packet domain • Synchronization protocol TM8106 Optical Networking - MPLS-TP

18. Synchronization (contd..) • Packet based clock recover solution • Adaptive Timing • Encapsulated and de-capsulated at packet edge nodes between TDM and packet domain • Differential Timing • Both edge nodes performing inter-working have access to reference clock TM8106 Optical Networking - MPLS-TP

19. Physical Infrastructure Support • MPLS-TP over SDH/SONET, PDH and OTN • ITU-T defines Generic Framing Procedure (GFP) • Encapsulate variable length payload of various client signal • Contains User Payload Identifier (UPI) • MPLS-TP uses same UPI point code as MPLS • OTN includes WDM network layer for transport of a variety of OTN client signals • SONET/SDH uses virtual concatenation to form transmission pipelines with larger capacities • MPLS-TP over Gigabit Ethernet • Two-octet long Ether Type field in Ethernet II Indicates which protocol is encapsulated in payload TM8106 Optical Networking - MPLS-TP

20. Deployment Options • Access and aggregation network • Major migration from circuit to packet happening nowadays • OAM enhancements will allow more visibility into Core TM8106 Optical Networking - MPLS-TP

21. Misconceptions about MPLS-TP • MPLS-TP is a new technology, not part of MPLS • It is a subset of MPLS with some enhancements • Extensions in MPLS-TP are not applicable in MPLS • Actually meant to apply in MPLS to make it broadly applicable • MPLS-TP requires substantial changes in MPLS • Design goal of MPLS-TP is to keep MPLS architecture • MPLS-TP require static provisioning • Supports both static and dynamic control planes • Requires forklift hardware upgrades • Might be true for some vendors, but not always, not in Juniper at least TM8106 Optical Networking - MPLS-TP

22. Conclusion • MPLS-TP is • Subset of MPLS/GMPLS • Enhancements esp. OAM • Fault management • Performance monitoring • E2E integration with existing and next generation MPLS networks • MPLS-TP intended to • Tie together • service routing • transport platforms • Advantages of tying together • Consistent operations and OAM functions across networks • Seamless interworking with IP/MPLS networks • Scalability due to multiplexing capability • Supports huge variety of services encapsulated into pseudowires TM8106 Optical Networking - MPLS-TP

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