WHITE PAPER OPTICAL EXPRESS The Key to Facilitating Cost-Effective and Efficient Network Growth Driven by a new generation of high-bandwidth consumer and business services and applications, the demand for bandwidth continues to pose significant challenges for operators of transport networks. This white paper explores innovations in Optical Express capabilities that can help network operators reduce costs, simplify operations, and extend service flexibility to a wider variety of network types and closer to the network edge.
INTRODUCTION Transport networks come in different shapes and sizes from transcontinental long haul (LH) networks and densely-populated metro networks to highly-distributed rural networks and enterprise networks. Additionally, transport networks are called upon to carry a tremendous variety of end-user services. While there are many different types of services e.g., mobile, residential, business, data center, carrier wholesale, etc. virtually every service will be carried by a transport network. In addition to requiring transport, virtually all services share another key attribute growth. In many cases, the growth required to support today s high-bandwidth services and applications is substantial, resulting in numerous challenges for network operators. DWDM AND OPTICAL EXPRESS Introduced in the 1990s, Dense Wavelength Division Multiplexing (DWDM) provides a cost-effective solution for managing bandwidth growth in transport networks. As highlighted in Figure 1, DWDM increases fiber efficiency by enabling multiple optical signals to be carried across a single fiber by transmitting each signal on a different wavelength, or color of light. The advent of tunable and pluggable lasers and advancements in passive DWDM filter technology (mux/demux) have created the technology foundation for efficiently expanding network capacity without the substantial capital and operational expense required when lighting additional fibers. DE FIGURE 1: DWDM ENABLES TRANSMISSION OF MULTIPLE OPTICAL SIGNALS ACROSS A SINGLE FIBER PAIR 2 OPTICAL EXPRESS
In addition, because DWDM signals operate at 1550 nm (or the C-Band), network operators can take advantage of cost-effective and readily-available optical amplification solutions to provide connectivity between greater distances without the need for costly electrical regeneration. However, while point-to-point DWDM can provide some relief for bandwidth growth, it is only effective at reducing fiber costs and will not significantly impact equipment costs. As bandwidth continues to grow, it becomes extremely cost prohibitive for network operators to continue to terminate services at every intermediate location. DWDM can help solve this issue with a capability called Optical Express. With Optical Express, individual wavelengths can be passed through intermediate locations exclusively in the optical domain. The economic benefits of Optical Express are significant, as optically expressing a service through an intermediate node is orders of magnitude less expensive than terminating that signal electrically. Optical Express 1 x $ 20 x $ Electrical Termination FIGURE 2: ECONOMIC BENEFITS OF OPTICAL EXPRESS 20 TIMES LESS THE COST OF ELECTRICAL TERMINATION The economic benefits of Optical Express are even greater the more locations and the more traffic there is in a network. Figure 3 illustrates a 5-node hub-and-spoke network where the total network traffic demand (the sum of all traffic from the hub to each of the end nodes) grows from 1x10G shared between all 4 destinations to a dedicated 10G to each of the 4 destinations. CORIANT 3
No Optical Express NETWORK COST Optical Express 1x10G 2x10G 3x10G 4x10G TOTAL NETWORK BANDWIDTH FIGURE 3: TYPICAL 5-NODE HUB-AND-SPOKE NETWORK CONFIGURATION The typical economic cross-over point between networks with Optical Express and those without is roughly 2x10G of total traffic. As illustrated in Figure 4, this could be a case in which one location requires a dedicated 10G and the other three locations share the remaining 10G, or each pair of two nodes share 10G. In either case, Optical Express capabilities will substantially reduce the total number of interfaces required by the network and subsequently provide a more cost-effective solution. Optically-Expressed Purple Wavelength Optically-Expressed Green Wavelength Optically-Expressed Purple Wavelength Optically-Expressed Green Wavelength FIGURE 4: POSSIBLE OPTICAL EXPRESS CONFIGURATIONS FOR 2X10G IN A 5-NODE NETWORK 4 OPTICAL EXPRESS
ROADMS AND OPTICAL EXPRESS While DWDM can provide a mechanism for Optical Express, providing this capability with fixed-filter solutions is largely a manually-intensive affair. With fixed-filter solutions (Figure 5), technicians must manually install fiber jumpers at intermediate locations, as well as manually and frequently balance wavelength power levels throughout the network. This high level of manual effort will significantly hamper bandwidth growth and significantly increase operational expenses. Amplification to compensate for filter loss Manual patch chords for pass-through traffic Amplifier Amplifier DE Amplifier Amplifier DE Manual attenuation to balance power FIGURE 5: LIMITATIONS OF FIXED-FILTER SOLUTIONS To overcome the operational challenges of supporting Optical Express capabilities with fixed-filter solutions, Reconfigurable Optical Add Drop Multiplexers (ROADMs) were developed. ROADMs enable remote provisioning of Optical Express connections and provide automated, per-channel power balancing across the network. As a result, when turning up a new service, manual effort is required only at the endpoints of the service (to physically install the new interface modules), while zero manual effort is required at the intermediate locations. ROADMs provide all of the economic benefits of Optical Express (Figure 6) while eliminating the operational difficulties of fixed-filter solutions. Automated balancing, integrated amplification, dynamic pass-through ROADM ROADM ROADM FIGURE 6: OPTICAL EXPRESS FACILITATED BY ROADM TECHNOLOGY CORIANT 5
THE BENEFITS OF ROADMS ROADMs provide numerous network benefits including facilitating trouble-shooting and reducing network complexity. However, the three primary and most significant benefits provided by ROADM-based networks are: Accelerated service-activation times Reduced regeneration costs Improved Network Reliability By eliminating manual intervention and dramatically simplifying network engineering, it is easy to see how ROADMs can dramatically accelerate service activation times often by as much as 80%. Additionally, because ROADMs can balance signal power levels more accurately than manual balancing, they provide better overall optical performance in the network. This improved optical performance will result in a reduction in the number of times a signal will require costly electrical regeneration before reaching its destination. Elimination of these expensive electrical regeneration points can save as much as 30% in equipment costs. Finally, based on network studies, a full 75% of service interruptions in a typical network are the result of human error. Because ROADMs eliminate a great majority of the manual and physical interaction when activating services, they have proven to reduce service interruptions by as much as 63%. SERVICE ACTIVATION TIMES NETWORK COSTS SERVICE INTERRUPTIONS 80% Improvement $ $ 30% SAVINGS $ 60% REDUCTION $ $ Fixed Filter ROADM Fixed Filter ROADM Fixed Filter ROADM ROADMs enable turning up services without any visits to intermediate locations and without any manual power balancing The automated balancing provided by ROADMs results in better optical performance and hence less money spent on optical regeneration Dramatically reducing the manual effort in service activation coupled with automatic precise power adjustments has proven to dramatically reduce service interruptions FIGURE 7: KEY BENEFITS OF ROADMS 6 OPTICAL EXPRESS
THE ECONOMIC CHALLENGE OF TRADITIONAL ROADMS To attain this level of automation, ROADMs are comprised of a number of different components that provide the various monitoring, amplification, balancing, and optical switching capabilities. As a result, ROADMs have traditionally been fairly expensive compared to fixed-filter solutions particularly the cost of initial deployment. Historically, a ROADM degree could cost as much as 2 to 3 times that of a fixed filter. This has resulted in ROADMs being primarily deployed only in large networks with a significant amount of bandwidth. TYPICAL ROADM DEGREE SPLITTER Input Amplifier Power Monitor Wavelength Selectable Switch (WSS) Output Amplifier Supervisory Channel FIGURE 8: TYPICAL ARCHITECTURE FOR A SINGLE ROADM DEGREE OPTICAL EXPRESS INNOVATION FROM CORIANT With the rapid rise in bandwidth requirements, the benefits provided by Optical Express capabilities are becoming more essential in a greater number and wider variety of networks. Optical Express-enabling technology innovation has been a focus at Coriant for a number of years. To that end, Coriant has developed several innovative solutions to reduce the overall cost and the first cost of technology to enable Optical Express capabilities. INDUSTRY S HIGHEST DENSITY MULTI-DEGREE ROADM The first of these solutions is Coriant s industry-leading, highly-integrated, multi-degree core ROADM solution the OADM-88-8D. With the OADM-88-8D, Coriant provides a complete ROADM degree with all of the necessary components packaged into a single-slot module that, at.83 RU per degree, provides by a considerable margin the highest density 8-degree ROADM solution in the industry. CORIANT 7
8 7 6 5 4 3 2 1 0 Vendor A Vendor B Vendor C Vendor D Vendor E Vendor F Vendor G Coriant FIGURE 9: ROADM DENSITY COMPARISON (RACK UNITS PER DEGREE) When deployed in the 6-slot Coriant 7100 Nano Packet Optical Transport Platform, the OADM-88-8D can provide 6 degrees in a single 5-rack unit shelf or 2 degrees with 4 slots remaining for service modules. Supporting up to a total of 8 degrees (across two shelves), 88 channels, and colorless and directionless options, the OADM-88-8D is the ideal solution for dense metro, regional, mesh-based, and select long haul network applications. CORIANT 7100 NANO PACKET OPTICAL TRANSPORT PLATFORM Coriant 7100 Nano with Two Single-slot OADM-88-8D 4 Interface Slots 20x10G (HDTG) 2x100G (HGTM) INTERFACE CARD INTERFACE CARD INTERFACE CARD INTERFACE CARD CORIANT 7100 NANO PACKET OPTICAL TRANSPORT PLATFORM Coriant 7100 Nano with (6) Single-slot OADM-88-8D ROADM Modules FIGURE 10: OADM-88-8D HIGHEST DENSITY, MULTI-DEGREE ROADM SOLUTION IN THE INDUSTRY 8 OPTICAL EXPRESS
FLEXIBLE, COST-EFFECTIVE AUTOMATED EDGE OADM One of the biggest challenges with ROADM solutions is the cost of the Wavelength Selectable Switch (WSS) technology, which is the key enabling technology of traditional ROADMs. This has prevented many network operators from deploying ROADM-based solutions, or has restricted ROADM deployments to only very high-density core metro and/or regional networks. With the Coriant Automated Edge OADM (OADMF8) solution, Coriant has taken an innovative approach to enabling the extension of Optical Express capabilities to more networks, as well as extending deployment closer to the network edge. The OADMF8 provides all of the best aspects of a ROADM solution including per-channel power balancing, variable gain amplification, and operationally-efficient Optical Express capabilities without the high cost of WSS-based devices. The OADMF8 supports 44 channels of total capacity with the ability to add and drop up to 8 wavelengths. As with the multi-degree core ROADM (OADM-88-8D), the OADMF8 is a single-slot module and is supported by the 7100 Nano Packet Optical Transport Platform. 36λ EXPRESS CONNECTION OADMF8 OADMF8 44λ DEGREE WEST (B) 44λ DEGREE EAST (A) 8 7 6 5 4 3 2 1 1 2 3 4 5 6 7 8 CLIENT ATTACHMENTS CLIENT ATTACHMENTS CH. 1 TUNED WAVELENGTH TRANSPONDER TRANSPONDER FIGURE 11: CORIANT AUTOMATED EDGE OADM (OADMF8) CORIANT INNOVATION EMPOWERING COST-EFFICIENT OPTICAL EXPRESS Figure 12 highlights the impact that Coriant s multi-degree core ROADM-on-a-blade and cost-optimized Automated Edge OADM solutions have had in driving down the cost of, and improving access to, operations-friendly Optical Express capabilities. CORIANT 9
1 START-UP COST 3 2 MULTI-DEGREE WSS- BASED ROADM CORIANT EDGE ROADM PASSIVE DWDM 09 10 11 12 13 14 15 1 / Coriant introduces the first multi-degree ROADM-on-a-blade 2 / Coriant introduces industry s highest-density, single-slot multi-degree ROADM-on-a-blade 3 / Coriant introduces innovative Automated Edge OADM FIGURE 12: REDUCING NETWORK COST AND COMPLEXITY WITH CORIANT OPTICAL EXPRESS SOLUTIONS CORIANT 7100 NANO PACKET OPTICAL TRANSPORT SOLUTION Both the multi-degree core ROADM and Automated Edge OADM are supported on Coriant s industryleading 7100 Nano Packet Optical Transport Platform. The 7100 Nano is a flexible 5-rack unit, 6-slot transport platform that supports grey light, passive DWDM, Automated Edge OADM, and multi-degree ROADM configurations while providing a seamless and cost-efficient migration path from one configuration to another. This capability enables network operators to begin by deploying the exact technology needed at any given time be it a grey light, passive, or Automated Edge OADM and then seamlessly and easily upgrade to any other configuration effectively creating a solution that can dynamically evolve as network requirements change. In addition to a seamlessly scalable optical layer, the 7100 Nano supports a wide variety of service interface cards including 10G/40G/100G transponders and muxponders, SONET/SDH grooming modules, OTN grooming modules, and packet-grooming modules. The 7100 Nano also features a meshed backplane which enables non-blocking grooming across all modules without incurring the upfront expense of a central switch fabric. Overall the Coriant 7100 Nano Packet Optical Transport Platform provides network operators with the industry s single most flexible metro/regional transport solution based on an innovative, cost effective, and seamlessly scalable optical layer coupled with a myriad of flexible electrical grooming mechanisms and fabric-less switching via a meshed backplane. 10 OPTICAL EXPRESS
7100 NANO SHELF OVERVIEW FLEXIBLE SCALABLE PLATFORM Universal Shelf architecture 480G Transparent; 120G OTN; 552G Packet 6 Slots per shelf - 8 shelves per system FULL INTELLIGENT SERVICES LAYER SUPPORT 10G, 40G, & 100G Transparent SONET/SDH, Packet, OTN Switching Full shelf fabric-less grooming via meshed backplane 4/8 Degrees 88 Channels per Degree w/ Full Add/Drop PACKET OTN 10G 100G ROADM SPM /DE FIBER THROUGH Low Cost Small Form Factor FIBER THROUGH FIBER THROUGH FIBER THROUGH FIBER THROUGH FIBER THROUGH FIBER THROUGH Grey Light System Passive DWDM Cost Effective Edge ROADM Multi-Degree Core ROADM 120G MSPP, 120G OTN SWITCH, 552G PACKET SWITCH 12X100G, 80X10G W/ EXPANSION PORT SHELF W/ TWO EXPANSION PORT SHELVES Seamless Growth FIGURE 13: THE CORIANT 7100 NANO FLEXIBLE FOUNDATION FOR OPTICAL EXPRESS FOUNDATION FOR SUCCESSFUL SDN IMPLEMENTATIONS Software Defined Networking (SDN) provides the ability to more dynamically control services in multilayer networks. However, dynamic control capabilities will always be limited by the actual connectivity capabilities of the underlying network that SDN solutions are controlling. Optical Express capabilities the ability to easily, quickly, and flexibly provide connectivity between any locations in a network provide an agile foundation for the kind of flexibility that will be necessary for any successful implementation of SDN. CONCLUSION As network operators struggle with designing future-proof transport networks capable of efficiently and cost-effectively supporting traffic growth without impacting service profitability or unreasonably burdening their operational organizations, enabling Optical Express capabilities will become more and more vital. With significant advancements in ROADM technology, coupled with the innovative solutions provided by Coriant such as the Automated Edge OADM, cost-effective and operationally-friendly Optical Express capabilities are now accessible to a wider variety of networks and can be extended closer to the network edge. CORIANT 11
ABOUT CORIANT Coriant, founded as an independent company in 2013, is an industry-leading supplier of dynamic metroto-core transport solutions. We serve over 500 customers globally, including 90% of the world s top 50 service providers. Our packet optical, edge router and Software Defined Networking (SDN) solutions enable mobile and fixed line operators to reduce network complexity, increase service velocity, and improve resource utilization as transport networks scale in response to a new generation of highbandwidth services and applications. Coriant was formed from the distinguished technology heritage and proven networking expertise of Nokia Siemens Networks Optical Networks, Tellabs, and Sycamore Networks. The company operates worldwide in more than 48 countries, with R&D centers in Asia, Germany, Portugal, Finland, Canada and the United States, as well as a state-of-the-art production center in Berlin, Germany. Visit us at www.coriant.com. These trademarks are owned by Coriant or its affiliates: Coriant, Coriant Dynamic Optical Cloud, mtera, and Coriant Transcend. Other trademarks are the property of their respective owners. Statements herein may contain projections regarding future products, features, or technology and resulting commercial or technical benefits, which may or may not occur. This publication does not constitute legal obligation to deliver any material, code, or functionality. This document does not modify or supplement any product specifications or warranties. Copyright 2014 Coriant. All Rights Reserved. 74C.0067 Rev. A 11/14