DWDM - OTN/ROADM Be smart when you plan your Network Krzysztof Bondarczuk, PhD, MSc, Eng. Network Implementation Engineer

Content Introduction to DWDM and OTN technologies 12/30/2018 12:05 PM Content Introduction to DWDM and OTN technologies OTN switching capability OTN supported DWDM Network Introduction to ROADM Key ROADM elements Example ROADM configurations Conclusions Key Message SharePoint can be discussed using the feature set. © 2008 Microsoft Corporation. All rights reserved. This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.

DWDM – Dense Wavelength Division Multiplexing DWDM defines: Transmission medium: Optical Fiber (SMF/LEAF) All-optical signal regeneration 1R – Reamplificaiton (EDFA/RAMAN) Channels multiplexing process Transmitted frequencies/wavelengths (ITU Grid 40λ/80 λ /160 λ) Optical modulation formats (NRZ, DRZ, ODB, DQPSK, PDM-BPSK, ePDM-QPSK)

OTN – Optical Transport Network OTN is a technology defining mapping of numerous types of legacy protocols into a single optical signal - OTU (Optical Transport Unit) to support long haul DWDM transmission Supports popular services: Ethernet, SONET/SDH, Fiber Chanel, ATM Fully transparent to the transmitted protocols. Supports transmission rates from 2.5G up to 100G ( shortly 400G) Enhances long-haul transmission by implementing Forward Error Correction (FEC)

OTN Hierarchy

OTN Hierarchy OTN provides separate layers between Client interfaces (Optical Data Unit layer) and DWDM Line interfaces (Optical Transport Unit Layer). Each layer has its own overhead containing separate set of alarms and communication bits

OTN Supported DWDM Network Tributary cards map client services into ODU signal Crossconnection card provides flexible switching matrix between tributary cards and line cards Line cards convert ODU signal onto OTU signal prior to transmission Service remains within OTU/ODU layers until its final destination.

OTU Frame Structure 1 7 8 14 15 16 17 3824 3825 4080 Alignm OTUK FEC OTUk OH OPU k payload OPUk OH Client signal mapped in OPUk payload ODUk OH Optical Payload Unit (OPU) Overhead– contains information about transported data type Optical Data Unit (ODU) Overhead contains client side alarms and performance monitoring bits, provides communication bits between client side interfaces Optical Transport Unit (OTU) Overhead contains line side alarms and performance monitoring bits, provides another set of communication bits between line interfaces and FEC section contains redundant information for errors correction at the receiver side

OTU Frame Stape-by-Step

Forward Error Corretion Forward Error Correction (FEC) is a technique of error control for data transmission, where the sender adds systematically generated redundant data to its messages The carefully designed redundancy allows the receiver to detect and correct a limited number of errors occurring anywhere in the message without the need to ask the sender for additional data FEC significantly improve OSNR range of the transmitted signal to maintain designated BER of the transmitted services over long haul distances

Forward Error Correction

OTN Cross-connections Capability

OTN Power Consumption 60A 60A 60A 60A Total Maximum Power consumption in this configuration: 3261W (68A) Hypothetical Maximum consumption 100A Recommended configuration (2+2)63A on the power plant Power Plants upgrades might be necessary 1Tbit/s (100x 10G) transmission 200 fibers to ODF 20 fibers to Mux/Dmux Proper fiber management is a MUST

OTN Fiber Management Single cabinet is designed to support 320 (2mm) internal fibers and 720 external cables Power cable separation from optical fibers is strongly recommended (e.g. under floor electrical cabling and top fiber raceways) Slack should be managed on the ODF not within cabinet Additional side fiber management cabinets will significantly simplify day by day operation

OTN Fiber Management

OTN Summary OTN technology allows for services grooming at the electrical level offering enhanced network flexibility and better bandwidth utilization. OTN hierarchy allows for efficient data aggregation from access to the backbone layer OTN naturally integrates with DWDM providing flexible scalable neworks OTN Supports long haul transmission by implementing FEC

ROADM – Remote Optical Add/Drop Multiplexer ROADM is a new approach for DWDM network design allowing for remote optical channels switching between multiple directions in order to reduce need for manual on-site intervention for new channels provisioning. Key element of ROADM is Wavelength Selective Switch (WSS) replacing Arrayed Waveguide Grating (AWG) used in legacy DWDM networks

ROADM – Remote Optical Add/Drop Multiplexer Very first WSS realizations were made based on Microelectromechanical systems ( Vulnerable to vibration and mechanical shock) Recently Liquid Crystal on Silicon technology has been introduced for ROADM applications

ROADM – Remote Optical Add/Drop Multiplexer

2D Directioned/Colored ROADM Simplifies provisioning of pass-through waves Site visit required for local terminal equipment reconfiguration Excellent solution for remote nodes D 40 D 40 M 40 M 40 I T L 04-1 I T L 04-2 B104 A A RDU 9 WSM 9 A101 A101 Direction 1/West Direction 2/East WSM 9 RDU 9 A101 A101 B B B104 I T L 04-1 I T L 04-2 M 40 M 40 D 40 D 40

Multiple-D Directioned/ Colored ROADM

Directionless ROADM

Directionless ROADM

ROADM Insertion losses

ROADM Networks testing beyond 40G In legacy DWDM networks channel performance was analyzed based on Out of Band OSNR measurements in-Band OSNR could be interpolated based on out-off-band measurement This is no longer possible for new modulation formats used for 40G ad 100G transmission since the channels occupy full 50GHz window and are partially overlapped. The noise floor is no longer visible and cannot be easily measured Some spectrum analyzers developed in-band OSNR measurement based on assumption the signal is fully polarized and the noise is fully depolarized This technique however is no applicable for formats utilizing polarization multiplexing

ROADM Summary ROADM supports remote DWDM network reconfiguration, Different locations can designed for the specific functonalieties 2D directioned/colored solution will will simplify pass-through channels configurations with minimal performance penalty. Multiple-D directioned/colored solution perfectly suits remote sites wave dropping can be implemented by local drop direction channel: colored or colorless. For big terminal nodes with multiple directions, human on-site intervention is still most efficient approach however might be supported by directioned/colorless solution.

400G 40G Flex 100G Trill Cluster FCoE OTN ASON MS-OTN 8800 Thank You!