Gazettabyte 100G Metro Position Paper

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100 Gigabit: The Coming Metro OpportunityA Position Paper by GazettabyteOctober 2011

Contents Summary Status of 100 Gigabit deployments 100 Gigabit networking drivers Network congestion Data centre, PoP interconnects and 100 Gigabit services Technology options for 100 Gigabit The IEEE 100 Gigabit Ethernet interfaces The 10x10 MSA Coherent transmission Non-coherent transmission The coming battle for the metro 100 Gigabit metro transport Direct-detection point-to-point Direct-detection WDM Coherent metro

Developments to watch How the metro technologies will play out Cost performance Pluggable form factor Power consumption and compactness Cost reduction roadmap and standards Position statement Conclusions Acknowledgements

Gazettabyte Roy Rubenstein

SummaryOne hundred Gigabit-per-second (100Gbps) optical networking technology is staking its claim in the network. Like 10Gbps, rst introduced a decade ago, 100Gbps can expect to be a bedrock technology for years to come. The technology is already carrying live trafc in the network core, albeit so far in a modest number of deployments. The industry has already settled on coherent technology for long-haul (>1,000km) optical transmission. In contrast, a variety of technologies will be used for the emerging 100Gbps cost-conscious metro market. These include direct-detection as well as coherent technology. Indeed several 100Gbps direct-detection and coherent choices for the metro have already been announced. The 100Gbps metro market is an attractive opportunity for equipment, optical module, optical component and chip makers though it will be challenging and ercely competitive. For any proposed 100Gbps metro technology to be adopted widely, it must meet several important requirements: Have an attractive cost-performance Have a relatively low power consumption and be compact - ideally pluggable. Have a product roadmap that maintains the cost-performance advantage. Direct detection has an important lead on coherent technology in terms of cost and pluggability. This gives the technology a window of opportunity before coherent comes down in price and becomes compact enough to t within a CFP. Coherent will eventually become the predominant 100Gbps technology for the metro. But coherent designs are relatively complex and developments in telecom take time. If that proves the case, then direct detection can expect to secure an important role in the metro.

Status of 100 Gigabit deploymentsThe rst 100Gbps optical transmission link was deployed by Verizon Communications in its European network in December 2009. Linking Frankfurt to Paris, the 900km route was already carrying more than 30, 10Gbps light paths. Since then Ciena (which acquired Nortel's Metro Ethernet Networks division that supplied the rst 100Gbps system) has deployed 100Gbps systems for a variety of customers including service providers xed and mobile, cable operators and large research organisations. Alcatel-Lucent, which launched its 100Gbps system in June 2010, says it has sold 1,000, 100Gbps lines, with 800 already deployed. And in September 2011, Innera announced its DTN-X platform based on a 5x100Gbps photonic integrated circuit that will transport data over a 500Gbps super-channel. The DTN-X will become available in the rst half of 2012 and is expected to reduce the cost of 100Gbps long-haul transport. Industry analysts are largely upbeat about the 100Gbps market. Ovum, Infonetics Research and LightCounting all expect strong demand for 100Gbps in the coming years, with volumes ramping from 2013-14. The one note of caution is sounded by market research rm, Telecom Pragmatics, which warns of industry hyperbole and that volume deployments of 100Gbps could be a decade away.

Infonetics' view is China could even accelerate the uptake of 100Gbps before 2013. China is planning a huge rollout of bre-to-the-x (FTTx) and the three main operators - China Telecom, China Unicom and China Mobile - are all interested in 100Gbps given the inevitable trafc growth in their core networks. China Telecom and China Unicom have strong requirements for 100Gbps dense wavelength division multiplexing (DWDM) systems and plan eld trials by the year end or early 2012, while China Mobile will skip 40Gbps and go straight to 100Gbps, says ZTE. Huawei says it has already conducted a trial with China Telecom and that some of the operator's provincial branches have conducted their own 100Gbps eld trials. The Chinese vendor stresses there will be 100Gbps commercial deployment in the coming months, highlighting the China's Yangtze River Delta region in particular. Service providers say that rst deployments of 100Gbps metro will coincide with long-haul deployments although volume deployments of 100Gbps metro will come later. Equally, while the content service providers that operate "mega-data centres" are very interested in 100Gbps, the technology is still too expensive when compared with 10Gbps. But once 100Gbps technology becomes available at a competitive price-point compared to 10Gbps, the transition to 100Gbps will likely occur quickly.

100 Gigabit networking driversService providers' adoption of 100Gbps optical networking technology has been to expand capacity on key congested network routes. But operators are looking at using the technology more strategically as they plan their next-generation backbones using 100Gbps and future, faster speeds - 200Gbps, 400Gbps and 1 Terabit-per-second (Tbps) - based on coherent detection technology. There is also a demand by content service providers to connect their data centres across the metro. And while multiple 10Gbps services are used now, adopting 100Gbps will bring operational benets. These 100Gbps drivers are now discussed.

Network congestionIP trafc continues to grow yearly. The causes for the trafc growth are well documented: xed broadband subscriber growth, expanding use of video, and the rise of smartphones that benet from new mobile broadband technologies such as HSPA and LTE. Video is by far the most data-intensive content format and is forcing operators to reconsider how they distribute and cache such content in their networks. These drivers will continue and trafc growth will remain exponential although it will slow. Cisco Systems' visual networking index has reduced the yearly xed Internet trafc growth forecast to 32% per annum through to 2015. Service providers use 10Gbps predominantly to carry the growing trafc in their IP backbones. Certain operators such as AT&T have already upgraded their backbone to 40Gbps. For particular congested routes operators have added 100Gbps light paths. For now 100Gbps optical transport technology is in its infancy. Systems vendors' 100Gbps systems are still signicantly more expensive than 10x10Gbps. This should not be surprising. System vendors' systems are rst-generation designs and they have sold relatively few units. In contrast, 10Gbps

technology has had over a decade of cost reduction and been sold in considerable volumes. So much so that 10Gbps continues to come down in price, presenting a moving cost-target for 100Gbps to match. Operators will pay a premium for 100Gbps if it solves network pinch-points since it is cheaper to adopt 100Gbps than light a new bre with the associated outside plant costs. This is how Verizon has used 100Gbps technology to date. But Verizon is also planning its next-generation network, upgrading the backbone to 100Gbps over the next two years. BT's core network, which carries the bulk of its IP, business and voice trafc, consists of 106 nodes: 20 in the inner core are fully meshed, and an outer 86-node core. The core network interfaces to some 1,000 Points-of-Presence (PoPs). The UK incumbent says it will deploy 40Gbps in the core before moving rapidly to 100Gbps. BT expects such deployments to start year-end 2011.

Data centre, PoP interconnects and 100 Gigabit servicesEnterprises and content service providers view 100Gbps technology as a way to enhance connectivity to their businesses and data centres to achieve greater operational efciencies. What is used today to transport services is one or more 10Gbps links. It is more cost effective at present to use Nx10Gbps services than adopt a 100Gbps interface due to their relative costs. The bulk of the services for the next 3-5 years will remain at 10Gbps, for example 10 Gigabit Ethernet and 8 Gbps Fibre Channel storage trafc. But managers of data centres want to reduce the number of 10Gbps links they have to manage by adopting 100Gbps links. Large content service providers such as Google and MSN already have multiple 10Gig links. They also have secured or even own bre. By moving to 100Gbps interfaces they improve equipment port density and free up space as well as reduce the number of ports they must manage. There is also greater capacity efciencies using a 100Gbps link than multiple aggregated 10Gbps ones. Such data centre requirements should be viewed as distinct from service providers' own core and metro network capacity upgrades using 100Gbps, although clearly enterprise and content service provider 100Gbps connectivity requests will impact the telcos' 100Gbps plans. Operators upgrade their core networks rst to 100Gbps and upgrade the metro at a later stage, once the technology comes down in price for the more cost-conscious metro market and once enterprises' requests for 100Gbps services grow in volume. Operators will eventually have requests from their customers for 100Gbps services. At present 10GbE services are sufcient for most enterprises' telecom requirements such as VPNs, phone and data requirements. But over time this will grow and once enterprises require several such 10 GbE services, a 100Gbps service becomes an option. Level 3 Communications expects it will take some ve years before 100Gbps service requests from enterprise become commonplace. In summary,