Network Latency


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To ensure a network built to support low-latency fulfills its potential, it’s
also critical to take a holistic systems-based approach to network management.

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Network Latency

  1. 1. White paper 2 The Situation 2 Types of Network Latency 2 WAN Design 2 Trading Network Design 3 Other Components toReduce Latency 4 Low-Latency StorageTable of Contents Ultra-low-Latency.. Networking..Facilitating real-time equities, futures, options and otherfinancial transactions nanoseconds faster can be worth millions.Executive SummaryLatency is such a hot topic on Wall Street that some believe it’sthe next big thing.It’s so big that well-known IT veteran Saro Jahani, currentlyCIO of the Direct Edge Stock Exchange, publicly stated at aconference that he wouldn’t be surprised “if the newest titleon The Street was that of a chief latency officer.”Although the “CLO” concept may be yet in its infancy, thedrivers for Jahani’s remarks are easily understood. With themost recent estimates on the impact of latency showing thatevery millisecond lost can result in $100 million per year in lostopportunity, it’s no wonder IT departments at securities firmsare making latency a top priority.In the global electronic financial marketplace, trading systemsare only as good as the infrastructure upon which theyexecute. Securities firms, regardless of size, are adoptinglow-latency networks to remain competitive in an industryincreasingly driven by computerized algorithm trading.TWEET THIS!
  2. 2. Ultra-low-Latency Networking2The SituationWhen it comes to algorithmic trading, everyone’s getting intothe game. No longer limited to a select group of large WallStreet players, now securities firms of all sizes use algos togain competitive advantage and improve profitability.For example, a 2012 survey, conducted by Automated Tradermagazine, found that more than 80 percent of buy-sidefirms currently use systematic algorithms to trade certaininstruments. And that number is expected to rise to97 percent within the next three years.Further, the subset of algo trading called “high-frequencytrading” (HFT) now accounts for more than 50 percent of allmarket volume, according to estimates posted by the TABBGroup, a financial markets research and advisory firm, in July.In a world where so much trading is systematic, milliseconddelays matter. Low-latency, high-performance networking,therefore, has become a competitive imperative.Types of Network LatencyWhen it comes to networking latency in the securitiesindustry, there are two general types: partner-based and firm-based latency.Partner-based latency: This type of latency is the timerequired by partner systems, such as an exchange ormarket data provider, to process messages within theirsystems. A firm clearly can’t control the performance ofits trading partners’ networks, but it can select partnersbased on network performance. To do so, insist on actuallatency measurements, not just service-level agreement(SLA) numbers.Firm-based latency: As the term implies, this type of latencyoriginates from within a firm’s networking systems. The sourceof latency — and how it’s driven out — depends upon the typeof network. These fall into three categories:•Wide area networks (WANs), which communicatemessages to and from trading and campus networksand external providers•Trading networks, which are dedicated to trading andoptimized for the purpose•Campus networks, which are for all business functions notrelated to the actual trading of equitiesWAN DesignCommunicating trading information to partners frequentlyoccurs over a WAN. Because few small and mid-sized firmslay their own fiber-optic networks, what’s most important isasking the service provider whether it utilizes low-latencyarchitectures. These include:•Passive optical components: In general, a low-latencyWAN is constructed of passive optical components thatdo not introduce any significant delay. Among these aremultiplexers, demultiplers and optical add-drop multiplexersas well as either erbium-doped fiber amplifiers (EDFA) orRaman amplifiers.•DCM: To remove pulse distortion over long distances,dispersion compensation modules (DCM) are superior todispersion compensation fiber (DCF) due to DCM’s enormouslatency advantages.•Non-FEC transponders: Transponders send, receiveand optimize signals over a fiber network. Forward errorcorrection (FEC) transponders introduce higher latencyvalue than non-FEC transponders. Therefore, the latterare preferred.Additionally, it’s worth considering the benefits of leasing darkfiber that the firm can light itself versus a “lit” wavelengthprovided by a communications service. All things being equal,dark fiber will provide a lower-latency solution. If a lit wavelengthmakes more sense, however, require the provider to supplyactual latency measurements rather than SLA metrics.Trading Network DesignIn recent years, it has become common to build a networkdedicated to algorithmic trading as a separate environmentfrom other business functions. This enables the deployment ofpurpose-built, ultra-low-latency networking components.One benefit of a separate trading network is cost-effectiveness. Ultra-low-latency components can requiremore upfront investments, making a dedicated tradingnetwork more affordable than deploying low-latencygear systemically.Also, trading environments typically are not virtualized at thistime. Current virtualization technology introduces latency,which defeats any benefits achieved by increasing either CPUor storage utilization efficiency. By segregating the tradingenvironment, a firm can still leverage virtualization in thecampus network and gain all the benefits virtualizing offers.Additionally, creating a dedicated trading network permitsmoving the environment to a colocation facility, eliminating thelatency discussed above when sending data across a WAN.A look at the factors affecting latencyover the last three decades1983 2011 ImprovedCPU Speed 1x10Mhz 4x3GHz › 1.000xMemory Size ≤2MB 8GB ≥ 4,000xDisk Capacity ≤30MB 2TB › 60,000xNet Bandwidth 3Mbps 10Gbps › 3,000xRound-trip Time (RTT) 2.54ms 80 µs 32xSource: It’s Time for Low Latency, Stephen M. Rumble, Diego Ongaro,Ryan Stutsman, Mendel Rosenblum and John K. Ousterhout,Stanford University, 2011TWEET THIS!
  3. 3. 888.706.4239 | 3Although sell-side firms have a track record of benefiting fromcolocation, buy-side firms are increasingly using colocationsites as their utilization of algorithmic and HFT trading grows.Other Components toReduce LatencyTo achieve algorithmic trading goals, securities firms also needspeedy processors, accurate clocks and efficient applicationsto run on top of low-latency network infrastructures.Ultra-fast processors: Six-, eight- and 12-core ultra-fastprocessors enable complex calculations and create accurate,detailed forecasts, simulations and data visualizations. Bydecreasing input/output latency and improving I/O bandwidth,today’s ultra-fast processors help reduce application latencyfrom microseconds to nanoseconds.Ultra-fast processors rev up not only trading applications,but also other securities firm apps such as real-timerisk management. Some manufacturers offer additionalhardware features for enhanced data security and improvedmanagement capabilities.In addition, chip companies continue to push the envelope,pointing to an even faster future. Intel began shippingexperimental 48-core processors to research institutions in2010. Last fall, AMD shipped 16-core processors based on itsnew Bulldozer architecture. Even startups are selling 16-, 34-,64- and 100-core processors.Precise time synchronization: To ensure precise time-stamping of market data, transactions, risk management andother applications, cutting-edge precision time appliancesprovide accuracy to the microsecond — some, even to thenanosecond – improving both regulatory compliance andcompetitiveness for capital markets firms.The latest time synchronization appliances gather datafrom global positioning system data and feature preciseclock management software that works in conjunction withsynchronization hardware. They support industry standardssuch as the Network Time Protocol (NTP) and Precision TimeProtocol (PTP) as well as high-speed network interfaces such10 Gigabit Ethernet and InfiniBand.Efficient applications: In the wake of the global financialcrisis, Wall Street firms are more focused than ever on cost-effectiveness, which extends to the return on investment theirapps provide. Trading software makers therefore strive todesign increasingly efficient transaction processing platformsthat lower transaction costs while providing high-qualitycustomer service.Application optimization adds another layer of efficiency byautomating the provisioning of computer resources in real timeto respond to demand. This not only improves a firm’s abilityto respond to sudden increases in trading volume, but alsoreduces the total cost of operations.Anatomy of a Low-Latency,High-Performance Trading NetworkAlthough networks at individual capital markets firms willcontain technologies most appropriate for the needs of theorganization, the following components can be essential tosuccessfully meeting low-latency goals.•High-speed interconnects: To ensure wire speed datarates, build trading networks using gear that supports10 Gigabit Ethernet, InfiniBand or both. This reducesserialization delay while protecting networks againstmicrobursts — short-term events that create network-clogging congestion.•Ultra-low-latency switches: Mainstream switchmanufacturers such as Arista Networks, Brocade, CiscoSystems, Juniper Networks, Mellanox Technologies andNetScout Systems all offer ultra-low-latency switchesdesigned for high-performance trading networks.These specialized switches offer capabilities specificto such environments, such as latencies measured innanoseconds. The three methods to measure latency are:first in, first out (FIFO); last in, first out (LIFO); and last in,last out (LILO).•Message acceleration: Although numerous reliableproviders offer message acceleration software, a newbreed of purpose-built, hardware-based accelerationappliances are now available from manufactures suchas IBM. They offer sub-millisecond latencies at volumesranging up to millions of messages per second. Frequently,both Ethernet and InfiniBand networking are supported.•Next-generation security: Similar to switches, purpose-built low-latency firewalls from manufacturers such asFortinet and SonicWALL supply multiple functions forunified threat deterrence without impeding networktraffic. Important characteristics include the ability tocontrol applications and also prioritize traffic.•Network management technologies: To ensure a networkbuilt to support low-latency fulfills its potential, it’salso critical to take a holistic systems-based approachto network management. From that perspective, twoessential technologies for low-latency environments arenetwork packet brokers (NPBs) and application-awarenetwork performance management (aaNPM).•NPBs: These purpose-built appliances, frommanufacturers such as NetScout, are intelligentswitches that connect network monitoring andsecurity tools to the underlying network. NPBscapture network behavior, provide packet-processingservices (such as deduplication) and distribute actionabledata back to security and monitoring tools, such asnetwork performance management (NPM) devices.•aaNPM: Although there are many NPM solutions, fortrading networks it’s vital to adopt a solution withthe intelligence of an aaNPM. These products providethe end-to-end visibility into the performance of thecritical applications that reside in low-latency, high-performance trading networks. Providers include Cisco,NetScout and Riverbed Technology.
  4. 4. Ultra-low-Latency Networking 4888.706.4239 | CDW.comThe information is provided for informational purposes. It is believed to be accurate but could contain errors. CDW does not intendto make any warranties, express or implied, about the products, services, or information that is discussed. CDW®, CDW•G®andThe Right Technology. Right Away®are registered trademarks of CDW LLC. PEOPLE WHO GET IT™is a trademark of CDW LLC.All other trademarks and registered trademarks are the sole property of their respective owners.Together we strive for perfection. ISO 9001:2000 certified108144 — 121016 — ©2012 CDW LLCLow-Latency StorageNo discussion of low-latency, high-performance networkingis complete without addressing latency contributed by harddisk-based storage.It’s well established that the performance of traditionaldisk storage is restricted due to the limitations of electro-mechanical devices, including access time, rotational latencyand data transfer rates. In combination, such limitationscan add significant delays into a network that is otherwiseengineered for low latency.Fortunately for the high-speed needs of capital marketsfirms, solid-state storage offers an efficient and cost-effective alternative.Solid-state storage solutions use integrated circuits, ratherthan rotating magnetic media, for storing data and aresometimes also called “flash-based storage.” Solid-statesolutions come in familiar form factors, including drive-shapeddevices or PCI Express cards. As a class, all types of solid-state storage devices are typically referred to as solid state-drives or SSDs.To understand the orders of magnitude in performancethat SSDs offer, a good metric is random input/outputoperations per second (IOPS). According to the StorageNetworking Industry Association (SNIA), an independentindustry organization, enterprise SSDs offer a 475 percentimprovement in IOPS over comparable enterprise hard drives.Once considered out of reach for small and mid-sized firms,solid-state storage solutions are now attractively priced,while costs continue to drop.Best of all, adopting SSDs doesn’t necessarily meanabandoning current hard disk investments. Some SSDs aredeployed as “Tier 0” in an existing storage subsystem. Otherstypes of SSD solutions can serve as a caching resource,allowing them to transparently run front-end current systems.To learn more about CDW’s low-latencysolutions, contact your CDW securitiesand investments account manager, call888.706.4239 or visit interconnect solutionsare some of the most deployedhigh-speed interconnects forlarge-scale simulations, replacingproprietary or low-performancesolutions by providing low-latency,high-bandwidth, high messagerate with complete transportoffload for extremely low CPUoverhead, remote direct memoryaccess (RDMA) and advancedcommunications offloads.Mellanox’s scalable high perfomancecomputing (HPC) interconnectsolutions are paving the road toExascale Computing by deliveringvery high scalability, efficiency andperformance for HPC systemstoday and in the future.Arista Networks has adopted anarchitectural approach to buildinglow-latency cloud networking. Itswire-rate, nonblocking and ultra-low-latency 1Gb/10GbE switches,along with Extensible OperatingSystem (EOS), enable resilient cloudnetworks for transporting data,multimedia, storage and computetraffic. Architecting cloud networks,based on Arista’s 7xxx seriesswitch fabric, offers ways to dothe following:•Reduce network latencies acrossall four axes•Future-proof the networkinfrastructure for latency demands•Implement standard Ethernet,which is widely deployed andoperationally well understoodMyri-10G, for high performancecomputing, provides the benefitsof Ethernet with performanceformerly available only in specialtyinterconnects. Myri-10G networkadapters for HPC support 1.2GbpsMPI ping-pong data rates, withavailable network adapter bondingboosting that rate to 4.5Gbpswith four network links. Kernel-bypass mode consistently deliverslow latency, even on multicoresystems. Zero copy implementationdramatically reduces host-CPUutilization, freeing up computingcycles to focus on computing tasks.Additionally, the technology cancarry TCP/IP and UDP/IP traffic atline rate for legacy CDW.comTWEET THIS!