An introduction to: WDM for IP/MPLS service provider networks Anders Enström Product Manager Transmode Systems

WDM vs traditional fiber networks Transponders & Muxponders Agenda Basic WDM overview CWDM & DWDM Optical Amplifiers WDM vs traditional fiber networks Transponders & Muxponders Flexible Optical Networks Packet optical networks Objective Obtain a basic understanding of WDM technology and how it is used in networks

WDM Basics

The receiver converts the light pulses back to digital information Optical Transmission 100100111001... Transmitter Receiver 100100111001... Optical fiber Optical transmission is the conversion of a digital stream of information to light pulses The light pulses are generated by a laser source and transmitted over an optical fiber The receiver converts the light pulses back to digital information

Wavelength Division Multiplexing Transmitter Receiver Optical fiber Wavelength Division Multiplexing (WDM) is based on the fact that Optical Fibers can carry more than one wavelength at the same time The lasers are transmitting the light pulses at different wavelengths that are combined via filters to one single output fiber

Wavelength spectrum & attenation Fiber Optical fibers have different Attenuation values over the wavelength spectrum for lasers Attenuation limits the reach of the optical pulses by reducing the optical power Best attenuation (0.25dB/km) is around 1550 – 1610 nm

CWDM & DWDM

Coarse Wavelength Division Multiplexing CWDM utilizes wavelengths from 1270 nm to 1610 nm Maximum 16 wavelength channels per fiber The bandwidth and spacing of the wavelengths allows for cheaper laser and filter technology compared to DWDM

CWDM Single-fiber & Fiber-pair 8ch per single-fiber 16ch per fiber-pair 8ch per fiber-pair In commercial confidence

Dense Wavelength Division Multiplexing CWDM Outside DWDM-band DWDM L-band DWDM C-band The DWDM spectrums have more narrow bandwidth and spacing compared to CWDM Increases total number of channels (typically 80) but lasers and filter components are in general more expensive The ”C-band” is the most used due to the availability of Optical Amplifiers

The choice between CWDM & DWDM is typically based on: Summary CWDM & DWDM The choice between CWDM & DWDM is typically based on: Distance to bridge Number of channels needed Data rates used Flexibility and expansion In general, CWDM is a cheaper technology more suitable for smaller aggregation networks in metro or access, for data rates up to 10G and reach up to 100km per span DWDM is a slightly more expensive technology suitable for larger backhaul networks with complex traffic matrix and higher capacity, with data rates up to 100G and reach up to 3000 km

Optical Amplifiers

Amplifier stations typically each 80-100km Optical Amplifiers 100km 100km Without amplifiers the reach is limited to 80-100km before electrical regeneration Optical amplifiers boosts the attenuated wavelengths and are more cost efficient than electrical repeaters Amplifier stations typically each 80-100km Depending on signal types and fiber characteristics, Amplified DWDM reaches typically up to 1500 km

Optical networks with amplifiers OK up to 80km SDH SDH What if the link is 240km? SDH 80km What if you have optical amplifiers? SDH 80km What if you want more channels? SDH 80km Restricted

Summary Amplified networks Amplifiers are used in DWDM networks and increases the reach of the optical signals up to 3000 km Amplifiers are a better choice than electrical repeaters and are usually distributed each 80-100 km Amplifiers and DWDM filters are the two basic building blocks for a powerful DWDM network

WDM vs traditional fiber networks

Dark fiber vs passive and active WDM Dark fiber solution + low cost interfaces + no cost for passive equipment high cost for fiber rental (one service per fiber) long provisioning times less flexibility in the optical layer short reach Passive WDM solution + no transponder cost + low cost for fiber rental + short provisioning times only possible for short distance no management or performance monitoring Active WDM solution - transponder cost + low cost for fiber rental + short provisioning times + transponders and client equipment could be in different locations + management or performance monitoring + aggregating services in muxponders for better wavelength utilisation + advanced networking functions, e.g. Protection, FEC, ROADM Restricted

Traditional networks (ring example) Cascaded nodes leads to complex redundancy schemes Different services (Ethernet, SDH) requires separate fibers or complex and expensive equipment (Pseudowire, Ethernet over SDH) Shared resources per fiber for all nodes Same type of equipment and uplink interface in all nodes

WDM aggregation (ring example) Easy mixing of service types (SDH, Ethernet, SAN etc.) per node Redundancy per individual channel Dedicated resources per node – no sharing!

Transponders & Muxponders

Transponders & Muxponders SDH/ SONET IP Router1 ʎ3 WDM link WDM Node Mux/Demux ʎ2 Transponder ʎ1 IP Router2 ʎ1 ʎ2 ʎ3 Muxponder

Generates the WDM wavelength Transponder Client signal Digital Wrapper WDM wavelength l Generates the WDM wavelength Line side Client side Transponder Client side ʎ Line fiber Line side framing enables performance monitoring, management channels and increased reach with FEC Client system

Generates the WDM wavelength Muxponder Client side SDH Client signals Digital Wrapper WDM wavelength FC Ethernet Muxponder Client side Line side l Generates the WDM wavelength Client systems Client systems ʎ Line fiber Line side framing enables performance monitoring, management channels and increased reach with FEC

Summary Transponders & Muxponders Transponders and Muxponders provides wavelength conversion from client to WDM signal A Transponder maps a single client to a single WDM wavelength A Muxponder multiplexes several lower speed client signals to a higher speed WDM wavelength, thus increasing the network capacity The digital framing of a line signal from a Transponder or Muxponder provides service monitoring, management connectivity and increased reach The broad range of available Transponders & Muxponders enables cost efficient solutions for both CWDM & DWDM

Flexible Optical Networks

ROADM networks ROADM – Reconfigurable Optical Add/Drop Multiplexer Used for increased flexibility in the optical paths Services can be redirected upon failure or capacity constraints Capacity can be increased dynamically per node

Basic ROADM principles Mux Mux

Flexible Optical Network – Key Components 4/17/2017 Flexible Optical Network – Key Components Multidegree ROADM Enables dynamic switching of services and reconfiguration of capacity in the network 8D ROADM 8D ROADM 4D ROADM 2-D ROADM Enables scalable growth of allocated capacity per add/drop node 8D ROADM 8D ROADM 2D ROADM Colorless MDU Enables scalability and ”lambda-free” planning and installation Each key component is there to lower the operational cost and shorter the service provisioning time. The multidegree ROADMs in the network enables flexible commissioning of new services across the network without manually visit the patch-through sites. The 2D ROADM enables an add-drop node to be upgraded and adjusted with capacity at any time, lowers the planning cost and any future replanning of capacity The colorless MDU allows a lambdafree planning and installation at the sites, no waste of Colored ports if the wavelength is occupied elsewhere. No need for skilled onsite engineers, use any available MDU port. The tunable laser is also a part of the lambdafree planning and installation, as well as an important part for lowering the sparepart cost. It also enables, in combination with the colorless MDU, a total reconfiguration of the installed service, for instanse redirecting a service due to relocation or redundancy or lambda conflicts. Tunable laser Enables dynamic reconfiguration of services down to the wavelength Limited

Summary Flexible Optical Networks ROADM’s provide more flexibility compared to fixed filters A wavelength can be redirected to another path if necessary Capacity planning becomes easier with dynamic expansion of add-drop wavelengths Remote software control – no site visits required Using ROADM’s, colorless filters and tunable lasers provides extensive flexibility Efficient reuse of deployed investments

Packet-Optical Transport Overview 4/17/2017 Packet-Optical Transport Overview

Layer 1 Transport  Packet Optical Transport 4/17/2017 Layer 1 Transport  Packet Optical Transport Layer 1 Transport Most suitable for: Carrier internal infrastructure Wholesale services Characteristics: Point-to-point, fixed speed 100% transparent (what goes in goes out) No service priority separation IP Provider Edge Router ~200M each 3 x1G 1G 10G 10G 10G S 5G 10G Mobile Packet Core 1+1+1G 200M 1G Service = client interface Wavelengths or sub-channels for each service Packet-Optical Transport Most suitable for: Business Ethernet services (E-Line, E-LAN, …) IP access network Video distribuiton Characteristics: Per-service routing, including multipoint Aggregation and QOS separation of services Flexible service rates IP Provider Edge Router ~200M each 3 x1G a,b,c 10G d,e 10G 10G d S 5G a,b,c e Mobile Packet Core 1G 200M 1G Service definition not tied to interface speed Services prioritized and aggregated within network Confidential

Native Packet Optical 2.0 for core agnostic service delivery MPLS-TP over Ethernet Native Ethernet Cisco Juniper Alcatel Ericsson Packet over OTU MPLS (LSRs LERs) IP Router Mobile SGW L3 Services Internet L3VPN IPTV L2 Services E-Line E-LAN E-Tree E-Access Ethernet (SVLAN, ERPS, …) Mobile services 3G LTE OTN (switching grooming) WDM foundation - Flexible Optical Networks Core network agnostic Confidential Restricted

Transmode L2 Solutions EMXP EDU NID iSFP-TDM Carrier Ethernet Services 4/17/2017 Transmode L2 Solutions EMXP Broadband aggregation Carrier Ethernet Services EDU Mobile backhaul L2 Packet Transport Business Ethernet Access Flexible ROADM- based WDM NID Legacy Services (TDM) iSFP-TDM Confidential

Summary

Summary WDM technology will increase the ability to scale a network with more capacity without using more fibers CWDM for smaller aggregation networks DWDM for larger and more flexible networks Flexible optical networks will enhance your network growth and reduce opex ROADM based networks superior in scalability and flexibility Integrated L2 functionality will give you the ability to sell advanced services directly over the fiber network and reduce the cost of routers and switches MPLS-TP and CE2.0 services on a wavelength

Thank you!