TM8106 Optical Networking
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Transcript of TM8106 Optical Networking
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TM8106Optical Networking
Multi-Protocol Label Switching-Transport Profile(MPLS-TP)
ByAmeen 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.
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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
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Transport Networks• Goal of transport network
• Requirements
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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)27.09.2012TM8106 Optical Networking - MPLS-TP
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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
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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
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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
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Standardization History
• ITU-T will define requirements
• IETF will work on protocol extensions
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MPLS-TP Components
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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
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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
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OAM Enhancements
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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
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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 plane27.09.2012TM8106 Optical Networking - MPLS-TP
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MPLS-TP Control Plane (contd…)
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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-TP27.09.2012TM8106 Optical Networking - MPLS-TP
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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
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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
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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 payload27.09.2012TM8106 Optical Networking - MPLS-TP
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Deployment Options
• Access and aggregation network
Major migration from circuit to packet happening nowadays
• OAM enhancements will allow more visibility into Core
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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
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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
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