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With 1 billion consumers owning smartphones by 2016, the demand for access to content through mobile devices alone is escalating at a feverish pace. In parallel with the tremendous growth in wireless, wireline traffic is also escalating as more devices become IP-enabled and more services shift to the cloud. Metro providers must meet these capacity demands while delivering superlative quality of customer experience, managing costs, increasing performance, and driving revenues.

Deployment of 10-Gigabit Ethernet (10GbE) in metro access networks is rapidly displacing legacy SONET OC-48 and OC-192, as 10GbE enables service providers to quickly address the unpredictable and rapid growth in bandwidth. Trends driving this transition include the convergence of high-speed Internet, digital home phones, and television services, which creates bandwidth demands per household on a single access line surpassing 12 Mbps. Additionally, the availability of LTE for mobile services is driving a minimal Ethernet connectivity demand of 100 Mbps per evolved NodeB – which connects to end mobile devices – with a required path to 1 Gbps per cell tower site.

Meanwhile, businesses continue to rapidly transition from Frame Relay and TDM services to IP/Ethernet services. Ethernet provides the ability to support cloud computing, convergence, and virtualization in the data center. Carrier Ethernet provides metro service providers with the increased network scalability, service-level agreement (SLA) enforcement, and comprehensive service operations, administration, and maintenance (OAM) features needed to meet IP-based communications requirements. Carrier Ethernet also offers service-oriented fault detection, verification, isolation, and notification capabilities to monitor performance and identify network issues for quick recovery.

Ethernet business services often have a starting point of 10 Mbps, and businesses require the ability to rapidly turn up additional bandwidth in 10-Mbps increments. For a customer on 1-Gbps access services, the provider wants to be able to turn on bandwidth in 100-Mbps increments.

Architectures based on 10GbE access (also known as multi-node) rings can drastically improve service reliability and deliver low latency and predictable jitter to achieve necessary SLAs. Legacy SONET OC-48 networks are not able to cost-effectively address the demand of IP/Ethernet connectivity.

While Ethernet is the technology preference, 1-Gbps access rings are unable to address the significant bandwidth demand. Which is why 10-Gbps access rings with 1-Gbps onramps is the new currency of the metro access network.
Why deploy 10GbE access rings?

Looking at this trend more closely, 10-Gbps has become the new coin of the metro access realm for several reasons.

Fast and seamless response to unpredictable bandwidth demands. Deployment of 10GbE access enables a metro service provider to quickly address changes in bandwidth demands. This ability contrasts with legacy SONET OC-48, which restricts the ability to rapidly turn up fine increments of bandwidth.

Combining 10GbE access rings with the scalability of a packet switch core network naturally accommodates bandwidth growth. As 10GbE access rings approach bandwidth saturation, either ring splitting or the simple addition of a parallel 10GbE wavelength with Link Aggregation (LAG) to the same packet switch core enables a seamless and rapid expansion of the access network.

Architectures based on 10GbE access rings are able to deliver five-9s (99.999%) service reliability. Legacy SONET networks have set the standard for high availability of the access network. Will moving to 10GbE change that? Carrier Ethernet technologies such as G.8032v2 have drawn from the SONET standards and have elevated Ethernet to the point where it can now outperform the reliability for legacy SONET networks.

Service OAM technologies such as Y.1731 for fault and performance monitoring are now standard offerings within Carrier Ethernet products. These protocols enable the monitoring and reporting of both the performance of the network and the services that are delivered.

With consumers and businesses embracing mobile technology at skyrocketing rates, device makers are outfitting smartphones and other devices with increasingly sophisticated media and content-handling capabilities and providing users with even faster network connections. Supporting this increase in data traffic growth places new requirements for backhaul connectivity. For mobile backhaul providers, this explosive growth of 3G and 4G mobile applications has to be met with appropriate cell tower site bandwidth.

Mobile service providers and owners of fiber-based networks have realized the value of fiber-to-the-tower and are aggressively bringing towers on-net to address the mounting demand for bandwidth. Levering 10GbE access rings with Carrier Ethernet technologies reduces fiber consumption, adds flexibility, enables scaling and raises the bar for SLAs for Ethernet connectivity services. In fact, mobile backhaul operators who have deployed 10GbE access rings with Carrier Ethernet technologies have been able to outperform the backhaul operators who have deployed legacy SONET networks for backhaul.

10GbE Carrier Ethernet access provides “near-0” latency and predictable jitter. There are many business requirements for low latency in the network, such as consolidated data centers. Information and data used across the enterprise need to be networked and shared with a “LAN-like feel” when physically consolidated into one data center (across the metro, region, or the nation). Remote business continuity and disaster recovery require disk mirroring and synchronous replication of data between primary and secondary data centers with a recovery point objective (RPO) near 0. RPO is expressed as an amount of time for the recovery of lost data. Financial services firms such as those involved in trading transactions must have optimized, low-latency connections between exchanges, electronic communication network (ECNs) points, and algorithmic trading data centers to rapidly execute the trades.

Low latency is achieved through Carrier Ethernet and 10GbE WDM by delivering:

    An engineered approach with optimized module and platform architectures for low latency
    Simplified transmission with Layer 1 for dedicated connectivity and limited payload processing
    Efficient signal processing through transparent transmission for efficient delivery to the WAN
    Optimized reach providing “near-0” latency technologies for amplifications and dispersion compensation.

Fiber constrained environments can benefit from mature WDM technologies. While once considered complex, expensive, power hungry, and restricted to long-haul networks, WDM technologies have dramatically matured over the last five years:

    The complexity of provisioning WDM networks has been addressed with dynamic optical layer approaches that combine ROADM, reach extension, and service management capabilities for enhanced automation of wavelength and packet-based services.
    Combining these technologies enables a service provider to turn up wavelengths across the network as simply as incrementally increasing the bandwidth for Ethernet services.
    The metro WDM technologies are now in their fourth generation, which translates into cost-optimized platforms, making it economical to deploy WDM in the metro access network.
    The power consumption of these systems has been dramatically reduced through continued advances in silicon processing power, coding technologies, and optical components. As an example, a 2RU platform with less than 100 W of power is able to provide transit capacity for 40 wavelengths and drop capacity for 8x10GbE.
    With all these advanced WDM technologies, delivering 10GbE wavelengths can be easily deployed in the metro access networks.

Moving to 10GbE is a great first step

Moving to 10GbE access networks from OC-3 or even OC-48 access rings can seem like a dramatic step for many capex-constrained service providers. However, increasingly this move is becoming the first step toward cost-effectively addressing the service and bandwidth demand of fixed and mobile consumers.

Capping of legacy SONET access rings and pushing all new service and infrastructure demands to Carrier Ethernet will maximize the return on investment for all service providers. In some cases, it may make sense to transition the SONET network from dedicated fiber pairs to wavelengths on a WDM access network. That same WDM access network can provide all the wavelengths required for 10GbE connectivity to support the roll out of a Carrier Ethernet infrastructure for E-service demands.

With the transition to an all WDM 10GbE metro access network underway, the service provider can focus on deployment of 1-Gbps Carrier Ethernet services to businesses, knowing that a low-cost-per-bit infrastructure will be in place to maximize the return on investment. Additionally, with the dynamic optical network in place, the service provider does not need to focus on forecasting unpredictable adoption bandwidth demands or the mix of wireline and wireless services. As the services delivered by the network mature and the bandwidth grows, the service provider can be assured that future demands can by addressed by the flexible, high-capacity architecture that forms the foundation.

Peter Green, P.Eng, is senior product manager for Carrier Ethernet at BTI Systems.

By Jon Anderson, Clearfield Inc.

With the advent of LTE/4G technology, our communication industry frequently hears and sees that copper T1 service to cell tower sites is quickly becoming inadequate. Wireless carriers continue to increase the number of new cell sites and to upgrade existing 3G sites to 4G/LTE. These carriers are more frequently requesting a minimum of 50-Mbps Ethernet initial service to these new tower sites and Ethernet upgrades to existing T1 services -- often with follow-on commitments to add 150-Mbps Ethernet service with just a three- or four-month notice.

This surge in cell backhaul bandwidth demand threatens to overwhelm facilities sooner rather than later. For example, historically the typical cell site might have been served with eight T1s. More recently, SONET ring networks were extended to include cell sites to facilitate dropping off a mixture of T1, DS3, and Ethernet type circuits. Now, not only is the number of new cell tower sites growing, but these sites are being designed to accommodate as many as six wireless carriers each. The result of this explosion in bandwidth is the need for fiber-fed connectivity based on Carrier Ethernet.

The emergence of Carrier Ethernet transport
The SONET unidirectional path-switched ring (UPSR) architecture continues to be very popular for mobile backhaul given its huge embedded base, variety of interfaces, and scalable bandwidths across OC-3/12/48/192 backbone rates. In addition, SONET offers proven reliability with less than 50-ms ring switching time.

Yet there is a new technology trend in network architectures to support cell-site tower locations – Carrier Ethernet transport. Typically these active platforms support Gigabit Ethernet to 10-Gigabit Ethernet backbone optics and are very scalable.

The drivers behind this new service provider model are quite logical: the ubiquity of the Ethernet interface (whether copper RJ-45 or optical 10/100/1000 Mbps), the advancement of ITU-T G.8031/2 standards for ring protection switching (also sub-50 ms), and five-9s of reliability. These technological advancements will enable Carrier Ethernet to become the predominant technology for serving the ever-growing demand for cell backhaul. In addition, the sheer volume of Ethernet chip sets across the application landscape has facilitated lower silicon component costs, greater availability, and reliability improvements.

At the heart of the acceptance of this network topology is Ethernet Protection Ring Switching (EPRS). EPRS was defined by the ITU and Metropolitan Ethernet Forum (MEF), is widely accepted, and continues to evolve into more complex network architectures with the recent announcement of Carrier Ethernet 2.0 by the MEF. ERPS began at ITU-T as part of the G.8032 Recommendation to provide sub-50-ms protection and recovery switching for Ethernet traffic in a ring topology while ensuring there are no loops formed at the Ethernet layer. G.8032v1 supported a single-ring topology and G.8032v2 supports multiple ring/ladder topologies.

Additional Carrier Ethernet service definitions are expected as new standards-based features are created, implemented in silicon, and deployed in active systems.

All of this bodes well for the continued use of Carrier Ethernet to meet 4G/LTE requirements for bandwidth increases and to expedite the push for fiber ring deployments to cell sites. In some sense cell backhaul is fast becoming the FTTx of the “Mobile Device Generation.”

Don’t neglect the Physical Layer
Yet with all of the technological advances on the active platform side of equation, service providers often neglect the challenges related to the Physical Layer until the installation and service due dates are almost upon them. With up to six cell carriers per new cell tower site and thousands of new tower sites popping up across the nation, service providers are understandably seeking deployment improvements, efficiencies, and best methods for delivering fiber handoffs to multiple carriers.

The cell-site location often represents a harsh environment in which to land these small- to medium-count fiber cables and involves special requirements for separate (non-shared) fiber facilities, separate demarcation points, lockable access fiber cabinets, outdoor NEMA 4 rated fiber cabinets, as well as hut-based fiber cross-connect panel/frame equipment. Existing fiber cable routes near cell sites may be small count, thereby limiting bandwidth without expensive fiber cable overbuilds. Wireless carriers may require multimode fiber cross-connect panel fiber connector/terminations to accommodate the lower-cost Gigabit Ethernet SFPs in their active platforms.

The fiber distribution portfolio used in these environments must address the basic challenges inherent in the central office/hub/outside plant/cell-site environments to gracefully improve fiber deliverability and fiber management for cell backhaul. The point of every component within a fiber management system -- from the cladding on the fiber, cable jacketing, optical component packaging, and the route paths within them -- is to protect and reduce the risk of fiber damage. Period.

Fiber distribution and management equipment that does not accomplish this in an easy and intuitive way is over-thought and costs you money. Fiber management should be approached with three simple goals in mind:

    The first and most important objective is to minimize your fiber risk in the cable plant.
    The second goal is to attempt to eliminate deployment and maintenance headaches.
    Third is to reduce the cost of broadband deployment via careful attention to not only lower capital equipment prices, but also lower operational costs.

Perhaps the biggest key to achieving these three objectives is to reduce risk by eliminating as much interaction with fiber jumpers and the fiber tail as possible. Fiber management equipment that integrates fiber distribution and slack storage within a small footprint enables the service provider to quickly and conveniently deploy the fiber as well as access it at a later time if necessary.

In addition, the costs of delivering the fiber to the site should not be overlooked. A simple in-ground drop cable would be convenient, but often is not possible. New developments in ruggedized microduct that enable service providers to push the fiber through existing conduit -- even environments previously considered exhausted -- are being brought to market and should be investigated.

Bringing together the whole package
While consumer demands for bandwidth will drive the use of Carrier Ethernet, careful system engineering and plant design will enable the service provider to create a backhaul network that economically meets the needs of the wireless carrier. Careful consideration of not only the active electronics but the physical layer as well as will ensure Carrier Ethernet is an economical business driver for the entire industry.

Jon Anderson is an applications engineer at Clearfield Inc. He joined Clearfield’s Market Segment Application Engineering team with nearly 40 years of experience in the telecommunications and data networking industry with companies such as Fujitsu, Teltrend, Lynch Communications, and Alcatel. He has direct engineering and application experience with a variety of optical platforms and technologies such as SONET (TDM), DWDM, Ethernet, and FTTx. Jon studied at Seattle Pacific University and Clover Park Technical College where he earned his degree in telecommunications.

Submarine capacity supplier GlobeNet, a subsidiary of Brazil’s Oi, will use optical transport equipment from Alcatel-Lucent (Euronext Paris and NYSE: ALU) in its recently announced project to link Colombia to its existing undersea fiber optical network (see “GlobeNet undersea cable route to link Colombia and Miami”). The equipment will provide GlobeNet the ability to support 100-Gbps wavelengths over the new 1000-km route, which will serve the need for broadband services between Colombia, the United States, and other Latin American countries.

Alcatel-Lucent will supply an integrated 100G-capable wet plant of cable and high-bandwidth repeaters, power feed equipment, and its 1620 Light Manager (LM) submarine line terminal equipped with coherent technology. The ultimate design capacity of the route will be more than 8 Tbps “on each connectivity path,” according to GlobeNet and Alcatel-Lucent.

The GlobeNet submarine cable system currently spans 22,000 km with landing points in Rio de Janeiro and Fortaleza in Brazil, Maiquetía in Venezuela, St. David’s in Bermuda, Boca Raton in Florida, and Tuckerton in New Jersey. The new extension will land on Colombia’s Atlantic coast.

Said Erick W. Contag, GlobeNet’s COO, “GlobeNet is committed to meeting the need for high-quality capacity to offer an improved experience for all of our customers. Our collaboration with Alcatel-Lucent is based on our confidence in the low latency, reliability, and speed of their solution, as well as their ability to seamlessly and efficiently introduce this extension to Colombia while maintaining all our existing network services.”

Powered by Aurora Networks’ Trident7® platform the national communications service provider in Andorra, now provide their 52,000 subscribers with the fastest upload and download speeds when compared to all other service providers worldwide. Andorra Telecom has strategically invested in a FTTH access network, convinced that true broadband is one of the pillars needed to become an excellent broadband communications operator.

Aurora Networks’ Trident7 PON solution enhances Andorra’s capability to deliver the right technology for emerging services such as IP video, OTT (Over-The-Top) video, and commercial services. With Aurora Networks’ solution, Andorra Telecom’s network can meet current market needs and service requirements, while also being ready for the service demands required in 7-10 years.

“Providing our customers with access to high value services is our priority. Being top of this list just reinforces that we are going in the right direction,” said Jaume Salvat, director general, Andorra Telecom. “With its flexibility and scalability, Aurora Networks’ Trident7 platform has provided us with the opportunity to deliver today’s advanced services with the quality of service and experience our subscribers have come to demand.”