Why 10-Gigabit Ethernet is the new bandwidth currency for metro access networks

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.

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.

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