1

OTN Overview

Radhakrishna Valiveti

System Architecture Group,

Infinera Corp.

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What is OTN?

Basic Capabilities in OTN Networks

New Developments

OTN Evolution Convergence of Layers

Summary

Outline

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Next Generation SONET/SDH Terabit/sec capacity on fibers (using DWDM) Higher client signal rates (1G, 2.5G, 10G, 40G, ...)

Transparent Client Signal Transport Bits & Timing

Support efficient multiplexing of services onto a wavelengths

Enhanced OAM Beyond SONET (no TCMs), SDH (1 TCM)

Protection schemes Linear Protection (support existing SONET/SDH mechanisms) Ring Protection (support existing SONET/SDH mechanisms) Shared Mesh protection (New)

What is OTN?

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First Gen DMDM Networks (pre-OTN)

Carrier B

Vendor B NE NE

Vendor A NE NE

NE NE

Proprietary DWDM solutions

Carrier A NE

NE

Carrier A

Customer Eqpt (e.g. Router)

Customer Eqpt (e.g. Router) Inter Vendor/Carrier interop

Possible only at the level of client signals

End to end Service realized in the form of multiple segments Client to wavelength mapping No end-to-end service management (only possibility is to examine the

client signal at various points along the circuit)

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The OTN Approach

Carrier B

Vendor B NE NE

Vendor A NE NE

NE NE

Intra-Domain interfaces (IaDI). Can incl. proprietary elements

Carrier A NE

NE

Carrier A

Customer Eqpt (e.g. Router)

Customer Eqpt (e.g. Router) Standard Inter-Domain (IrDI) i/f

Digitally wrap Client signals. Wrappers can be monitored in transit Monitoring:

Connectivity Verification Connection monitoring: end-to-end, or in segments

Maintenance Signals Generic Communication Channels

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Network View

IP Layer Routers Links Realized via Xport networks

IP

Electrical: Client Mapping, Connection Multiplexing, Grooming, Monitoring, No stranded BW Protection/Restoration

OTN

DWDM

Optical Layer: Add/Drop, Express, Protection/Restoration

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OTN Architecture

Client OH Optical Payload Unit (OPUk) (transparent client signal transport)

OPUk OH

FEC OH ODUk

Optical Data Unit (ODUk)

Optical Transport Unit (OTUk)

Optical Channel (OCh) (1 OCh per OTU; ITU G.694.1 wavelength grid)

OMSn

OTSn

Optical Multiplex Section (OMS)

Optical Transport Section (OTS)

Multi-Service Clients

Dig

ital

Do

main

Op

tical

Do

main

SONET/SDH SAN Ethernet

OCh

OCh

. . . . . . . . . . .

(k = 1/2/3/4 for 2.510/40/100G) FEC Enhanced optical reach, BER

No

n A

sso

c O

H (

OSC

) A

sso

c O

H

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OTN NE Internals CLIENT LINE SWITCHING

Client signal

adaptation

OTN

(O

TU1

, OTU

2, O

TU3

, OTU

4)

Eth

ern

et

(1/1

0/4

0/1

00

Gb

E)

SON

ET/S

DH

(1

55

Mb

/s

40

Gb

/s)

SAN

(F

ibre

Ch

ann

el, F

ICO

N)

l1

l2

l3

ln

l4

l1

l2

l3

ln

l4

ODUk Bandwidth Management

. . . .

. . . .

OD

U

Mu

x/d

emu

x

OTU

So

urc

e/Si

nk

OTN Client Interfaces

OTN Bandwidth Management

OTN WDM Line Side

Multi-service support for SONET/SDH, Ethernet and SAN

OTN handoffs enable multi-vendor inter-working

Optical interfaces support (OTUk) (Fully standardized)

G.694.1 wavelength grid

G.709 Digital Wrapper w/ FEC or Enhanced FEC

Typically OTUkV (Functionally standardized)

OTN Overhead & OAMP

ODUk switching

Typically ODU0 (1.25G) granularity

Transparent switching of DWDM line capacity

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OTN Layers (End-to-End View)

ODU

Client Eqpt

Digital ADM

Optical ADM

Optical ADM

Digital ADM

Client Eqpt

Optical Amp

OTS OTS

OMS

OCh

OTU

Client Signal Trail: e.g. OC192, STM-64, 10GBASE-R

May be part of the same NE

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Client Signal Mapping (G.709 3/2003)

CBR2G5 AMP OPU1

BMP

CBR10G AMP OPU2

OPU1-4V BMP

CBR40G AMP OPU3

OPU2-4V

OPU1-16V

BMP

OC-48/STM-16

OC-192/STM-64

OC-768/STM-256

No Standard Mappings defined for Ethernet Clients * AMP = Async Mapping Procedure; BMP = Bitsynch Mapping Procedure

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GMP 40GBase OPU3 TTT

GMP 100GBase OPU4

GMP STM-1,4 OPU0

GMP 1000Base OPU0 TTT

10GBase BMP OPU2e

FC-1200 BMP OPU2e TTT

CBRx BMP OPUFlex

Client Signal Mapping (G.709 12/2009)

* GMP = Generic Mapping Procedure; TTT = Timing Transp. Transcoding OTN fully support Ethernet Clients

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ODU Multiplexing Hierarchy

Low-Order ODUk

ODU0

ODUflex

ODU1

ODU2

ODU3

ODU3e1

ODU3e2

ODU4

ODU3e1

ODU3e2

ODU1 Muxing

ODU2 Muxing

ODU3 Muxing

ODU4 Muxing

ODU3e1/2 Muxing

ODU1

ODU2

ODU2e

ODU3

ODU4

High-Order ODUk

ODU1

ODU2

ODU3

ODU4

2 8 32 80

4

8 32 80

16 40

4 10

3 10

2

4

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OTN Multiplexing - Example

OTU3 OTU2e

OTU2

10GbE mapped into ODU2e

OD

U2

e O

H 10G

10GbE

10G

OD

U2

e O

H 10G

ODU2e muxed into

ODU3

OD

U2

e O

H 10G

OD

U3

O

H

OC-192/STM-64 mapped into ODU2

OD

U2

O

H 10G

OD

U2

O

H 10G

10G

OC-192/ STM-64

OD

U2

O

H 10G

ODU2 muxed into same

ODU3

ODU2 OH

10G

ODU3 OH

Client service

ODU2 encapsulation

ODU3 encapsulation

Legend

ODU2e OH

ODU2e encapsulation

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Tandem Connection Monitoring

OTN Network A

OTN Network B

OTN Network A

ODU Connection monitored within B (TCM1)

ODU Connection monitored within A (TCM2)

TCM1 & TCM2 being monitored concurrently Network operators need to agree on the TCM layers to use (no dynamic allocation

of TCM layers to domains) Allows arbitrary nesting of TCM layers (subject to layer availability) ODU frame includes Overhead (OH) for 6 TCM layers

TCM layer Used for: - Connectivity Verification, PM, Protection/Restoration triggers

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Tandem Connection Monitoring (TCM) Segment Protection/Restoration

OTN Network A

OTN Network A

ODU Connection monitored within B (TCM1)

ODU Connection monitored within A (TCM2)

detects the problem with the working path

Knows the problem is in their domain

Switches to the protection path

NE at the edge of Network B

Gets (data plane) notification of defect in working path

Uses hold-off timer to prevent initiating switchover (i.e. allow the nested protection attempt to succeed)

NE at the edge of network A (near CPE)

OTN Network B

working

protection

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Control Plane in Optical Networks

Auto discovery of topology

Route computation

Point-and-click provisioning

Service restoration

RSVP-TE signaling protocol for dynamic provisioning of paths Speeds service delivery from A to Z

OSPF-TE discovers topology & bandwidth Dynamically advertised as changes occur

Source-based CSPF circuit routing Traffic engineering for explicit routing control

Mesh restoration of multiple failures. Efficient use of bandwidth

Automated control plane for DWDM & OTN

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ODUflex Applications

Stop the proliferation of ODU containers Suited to CBR signals of arbitrary rates,

e.g. map 8GFC into ODUflex, NOT 8GFC to ODU2

ODU2e used to map 10GBASE-R signal is not called ODUflex (but can be considered the first ODUflex)

No need for deskew buffers required to support ODU VCAT

New use for ODUflex Packet Traffic rates not coupled to that of

the physical interface (logical flows) Uses GFP-F encapsulation for packets ODUflex rate is N x (TS in HO-OPUk)

Improvement over ODU VCAT

FC

Eth

TDM CBR

ODU-flex 1

ODU-flex 2

ODU (non-flex)

Higher Order (HO)

ODU (one l)

Eth

TDM CBR

ODU-flex 1

ODU (non-flex)

Higher Order (HO)

ODU (one l)

ODU-flex 2

VLAN #1

VLAN #2

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80 tributary slots @ 1.301G (for ODU4 links)

LO ODUj can take any n tributary slots

No bandwidth fragmentation

LO ODUflex(GFP) is resizable hitlessly (without any traffic impact)

HO ODU4/21 80 TribSlots @ 1G

ODUflex(GFP)/3

ODU2

ODUflex(GFP)/6

ODUflex(3GSDI)

ODU0

ODU0

ODU0

Unallocated TribSlot Allocated

TribSlot

/ 4

ODUflex Tributary Slot Allocation

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Convergence of Layers

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Private Line

SONET transport

Co

re /

Bac

kbo

ne

Net

wo

rk

The motivation behind Packet-OTN

IP Core Routers

Transport Network (OTN/WDM)

IP Peering

IP-VPN L2 VPN Internet Access

IPTV VoIP

Service Routers

Wholesale Bandwidth

SAN

Reduce Cost: IP core routers touch 100% of IP traffic at most nodes

Ensure Common convergence layer: Optical + Packet Support

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P-OTN optimized for packet & multi-service optical

2011 Infinera Corporation.

Today Phase I

IP/MPLS

STS/OTN

WDM

Converged WDM/OTN Switching

IP

MPLS

Phase II

IP

Converged WDM/P-OTN

Converged WDM/P-OTN dramatically simplify the network

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Summary

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Full function OTN

ODUk (N x ODU3)

OTUk (OTU4)

OTN DWDM Transport

Control Plane & OAMP

e.g., GMPLS, ASON, WSON

ODUj ODUk (ODU2 ODU3)

OTN Multiplexing

client ODUj OTN

OTN

OTN

OTN

OTN

OTN Adaptation

ODUj (ODU2)

ODUj (ODU2)

OTN Switching

Support For Full Range of Fully-Standardized OTN Features

10GbE -> ODU2

Standardized Multi-Service

Platform

Efficient Service

Reconfiguration

High Bandwidth

Inter-Carrier Hand-Offs

Efficient High-Bandwidth Transport

Multi-Layer Management & Automation

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Efficient OTN Enabled Network

Single OTN Service Delivery Layer Single protocol-agnostic service delivery layer

Homogenous OAM&P

Standardized Managed multi-service trunks Tandem Connection Monitoring

100% Transparent transport Asynchronous mapping Bit Synchronous mapping Generic mapping

Integrated OTN + DWDM

SDH Ethernet

Fiber Channel Others

OTN

Carrier A

TCM Level 1

Level 2

Level 3

Domain & Domain Interconnect Supervision

Lead Operator QoS Supervision

User QoS Supervision

OTN

Carrier B

OTN

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Thank You