Creating a Foundation for Profitability white paper Strategies for Operational Efficiency at the Metro Edge “Within the metro will be the need to install, test, and reconfigure all types of equipment with the same fundamental operational procedures and principles used in large, carrier-class networks historically Any other approach is inherently risky.” — Michael Day, CTO Today service providers are challenged to satisfy cost-conscious, yet broadband-savvy customers demanding high network reliability and feature-rich service offerings, all at economical prices To meet this challenge, service providers must strive to be efficient, reliable, and scalable while rolling out new revenue-generating services With capital expense under scrutiny, most service providers are finding an evolutionary approach to be the most viable strategy for maximizing the value of embedded equipment while migrating to next-generation services As a result, legacy platforms such as SONET/SDH and DWDM, originally optimized for traditional circuit-switched voice services, now are leveraged to handle a wide array of data services Yet as new services such as bandwidth-on-demand, IP VPN, and others gain popularity, service providers are building the metro to more efficiently carry these new, as well as legacy, services As a result, the number of fibers and network elements in the metro is multiplying and connectivity is playing an increasingly critical role as a foundation for operational efficiency and ultimately, profitability Given the variety of services and technologies deployed in the metro, no single technology will likely prevail as a sole platform so multiple technologies will co-exist Traditional circuit-switched platforms will share the central office and remote terminal with new packet-switched platforms The network will continually evolve to accommodate new services and technologies The key to managing this ever-changing and increasingly complex network architecture is to install flexibility in the face of uncertainty With a well-planned network foundation, service providers can support key services with carrier-class quality and reliability, while controlling costs for network management and operations The solution is simple By migrating carrier-class connectivity products and practices to the metro edge, the physical layer becomes easier to manage throughout network evolution A wellplanned connectivity infrastructure provides critical rerouting options, enables network monitoring and troubleshooting, and lays the foundation for a future-proof infrastructure that accommodates change and growth without disrupting service Simplicity within a complex network While equipment vendors often display clean and simple network diagrams showing the deployment of network elements, the reality is that integrating new-world network elements into legacy networks and scaling to accommodate growth is complicated at best New multi-service platforms with optical interfaces are entering the metro network, offering the promise of greater bandwidth and greater revenue opportunity However service providers are now challenged to manage unprecedented amounts of fiber in the metro Simple factors such as managing the proliferation of fiber cables, defining procedures for upgrading and expanding modular network elements, and selecting among the vast array of optical connectors are now critical to keeping operational costs down and minimizing risk As network elements increase capacity and accept more incoming and outgoing fibers, a greater need for high-density cable management within and around active equipment elements is evident Proper fiber cable management remains critical to preserving signal integrity and becomes increasingly vital as fiber counts multiply The four critical elements of fiber cable management – bend radius protection, cable routing paths, cable access, and physical protection – all directly impact the reliability, functionality, and operational cost of the network Simply put, poorly managed and unprotected fibers are more likely to bend and break, cause service failures, and increase network operational costs Proper protection within and around equipment elements not only enhances the long-term reliability of the fiber cables, but also reduces signal attenuation and enables service providers to realize fiber’s competitive advantage Most new-world equipment platforms feature modular line cards designed to ease upgrades and growth while minimizing initial capital expense While this modularity can increase flexibility, it can also increase complexity at the physical layer These devices require significant interoffice communication between network elements, leading to a complex connection scheme that can become a burdensome operational expense if not properly managed with a foundation of physical layer connectivity Each time a new line card is added or upgraded, it is not uncommon to require substantial connectivity changes For example, to upgrade a line card, as many as to 16 connections may need to be recabled When deploying hundreds of new lines per month, service providers can quickly face a time-consuming, labor-intensive challenge With a well-designed connectivity foundation, technicians can add or upgrade the same cards with minimal time and effort using the functionality of optical cross-connect frames or panels “In spite of everyone’s best wishes to for network reconfiguration This long-term operational efficiency quickly offsets the one-time capital investment simplify the network, the reality is that made in connectivity gear, which is typically less than valuable equipment is already deployed 10% of the cost of network element deployment and delivering service to customers This Another factor contributing to complexity in today’s equipment will continue to add value metro network is the proliferation of optical connector while new platforms are integrated into styles While a constantly increasing and divergent array the network We will have to live in a of connectors offers service providers many choices, it can also lead to increased costs for managing an mixed environment of legacy and nextextensive fiber jumper inventory with various lengths generation equipment for the and hybrids A simple solution can be to standardize on one connector style for all connectivity gear, which can foreseeable future and will be challenged serve as an interface point to various network elements to manage risk during this transition.” Through this approach, service providers can reduce the — Michael Day, CTO varieties of fiber jumpers in inventory dramatically, reducing overhead and administrative costs Migrating proven craft practices Today’s technicians face many new challenges: installing and maintaining new-world equipment elements, handling more and more optical fiber, understanding an expanding portfolio of technologies, all while meeting customers’ increasing expectations for provisioning and maintenance responsiveness As complexity and challenges mount, carriers are finding that standard central office practices are now instrumental for operational efficiency in the metro Network Element Network Element Tx OUT Rx IN Rx IN Tx OUT Permanent Equipment Cables Figure Typically, high-volume central offices centralize craft practices around common connectivity interfaces that remain constant regardless of changing technologies Technicians become accustomed to a common work interface and, as a result, can accomplish day-today tasks faster and with fewer training hours required to keep pace with evolving network technologies In the metro edge, a connectivity Network Element foundation offers similar benefits Technicians can conduct day-to-day provisioning and maintenance activities at a centralized connection point using common craft practices, enabling speed and efficiency Likewise, a centralized termination point isolates day-to-day work from highly sensitive equipment backplanes and minimizes risk of inadvertent damage to expensive equipment elements or disruption of adjacent circuits Network Element Network Element OUT Tx OUT Rx IN IN Rx IN Permanent Equipment Cables IN OUT Permanent Equipment Cables Tx OUT Figure Network Element Tx OUT Tx OUT OUT OUT IN Rx IN Permanent Equipment Cables IN Semi-Permanent Equipment Cables Rx IN Permanent Equipment Cables Figure As smart network architects plan for network design, it is critical to take into account these real world craft practice implications The three methods of connecting equipment – direct connect, interconnect, and cross connect – are critical to compare and evaluate for operational efficiency The direct connect method (figure 1), sometimes called “hard wiring,” involves directly joining network elements without a central intermediary point Initially, this option seems ideal given its low upfront cost Yet as service is deployed and additional equipment is added to the network, hard-wired connections quickly prove to be unscalable and operationally unmanageable This approach to connectivity is often implemented without the realization of the operational impact – new services take longer to add, new network elements are difficult to integrate into the network, and network operations are ultimately more cumbersome and expensive Comparatively, the interconnect method (figure 2) provides a common termination point between equipment elements and is often provisioned with some means of slack storage for fiber cables Because each network element is connected to a central termination point, technicians can more efficiently conduct day-to-day testing and maintenance operations If minimal network reconfiguration is anticipated, an interconnect architecture can work, but the more a network changes, the more desirable a cross-connect architecture becomes A cross-connect architecture (figure 3) provides the greatest flexibility for future network reconfiguration and greatest efficiency in craft practice All fibers are connected to a central termination point with semipermanent cross-connect jumpers routed between ports of the fiber distribution frame or panel This makes accessing the network elements easier, enhances technician efficiency, and improves the long-term reliability of the fiber network A cross-connect system with strong, flexible slack storage provisions will significantly minimize long-term operational costs in an ever-evolving metro network Careful choices in network design can support growth and change as the metro network evolves By selecting flexible, craft-friendly architecture, service providers can maintain a sound balance of capital and operational expenses while enhancing efficiency in the metro Minimizing operational risk Network upgrades and improvements often result in more functionality in network elements and more bandwidth on facilities and local loops As these new technologies concentrate and accelerate the delivery of revenue-generating services, the risk of outages, downtime, and decreased performance is amplified The selection of network connectivity elements and practices is paramount to mitigating this risk “Though many network elements feature integrated test points, carriers should position passive test points independently to minimize risk of disrupting adjacent fibers or damaging expensive line cards and electronics When the test interface is the same for each application and As greater amounts of fiber move into the metro, for network element, craft practices can be example, field-termination of fiber connectors may no simplified and risk can be minimized.” longer be the best practice To improve craft efficiency and enhance network reliability, factory-terminated — Tom Kampf, Program Manager, connectors may be the best choice to relieve technicians Fiber Products of the requirement to field-terminate an ever-increasing number of fibers Since field connectorization requires a skilled technician pool, labor costs can accrue quickly and reliability can be jeopardized as technicians attempt to quickly terminate a large volume of singlemode and multimode fibers Field connectorization may seem less expensive at the time of purchase, but extraneous expenses encountered in the field increase cost and risk rapidly Factory connectorization, on the other hand, minimizes installation expenses and risk by ensuring that connectors are polished, terminated, and inspected in a factory-controlled environment Likewise, factory termination enables high-quality, rapid connector installation by less experienced craft personnel and minimizes labor costs While factory-terminated cables may not necessarily be the right lengths for every equipment connection, network designers can accommodate by arranging for slack storage within the network infrastructure plan Multi-fiber ribbon cables are gaining popularity as a valuable way to increase density per line card Without the ability to break out individual fibers from a multi-fiber ribbon cable, service providers risk disrupting high-volume, high-value traffic carried over the entire cable rather than simply addressing the issues related to traffic on a single optical fiber Operational efficiency and network reliability can be impaired if these multi-fiber ribbon cables are not deployed with a connectivity interface that enables technicians to break out individual fibers for testing and reconfiguration Addressing the need for test access is critical to assess network operations at multiple points for troubleshooting, repair, basic monitoring, and to ensure quality of service Physical test points should be positioned between electronic devices and at demarcation points where signal handoff occurs between carriers or to an enterprise network Through these access points, technicians can monitor signal integrity to isolate faults to a particular equipment element or segment of the network This approach not only speeds troubleshooting time, but also minimizes “fingerpointing” between various carriers when a technician can identify which network is the source of a failure The risks inherent in joining diverse equipment, building new infrastructure to support metro traffic, and ensuring quality of service are real but manageable with a solid connectivity foundation The time to think of connectivity is now – while a majority of the metro is under construction and real operational efficiencies can be designed into the network infrastructure Web Site: www.adc.com From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 For a listing of ADC’s global sales office locations, please refer to our web site ADC Telecommunications, Inc., P.O Box 1101, Minneapolis, Minnesota USA 55440-1101 Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice At any time, you may verify product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents Products or features contained herein may be covered by one or more U.S or foreign patents An Equal Opportunity Employer 1240832 11/02 Original © 2002 ADC Telecommunications, Inc All Rights Reserved ... designers can accommodate by arranging for slack storage within the network infrastructure plan Multi-fiber ribbon cables are gaining popularity as a valuable way to increase density per line card Without... cables, but also reduces signal attenuation and enables service providers to realize fiber’s competitive advantage Most new-world equipment platforms feature modular line cards designed to ease... connectivity Each time a new line card is added or upgraded, it is not uncommon to require substantial connectivity changes For example, to upgrade a line card, as many as to 16 connections may need