ABI Research expects 802.11n access point shipments to take off over the next five years.

Business Class 802.11n Ready to Deploy New Equipment with Backward Compatibility and Future- Proof Standards Helps Organizations Boost Performance and Deliver on the Latest Wireless Applications White Paper Abstract Today s Web applications, IP video streams, VoIP systems and mobile devices are placing more and more demand on wireless networks. Every day, users at hotels, office lobbies, trade show floors, meeting rooms, and convention halls break out all manner of laptops, dual mode phones, netbooks, PDAs, and mobile devices expecting to connect to a wireless LAN. Wireless connectivity is rapidly becoming a utility, like power outlets in the air. Consequently, enterprises of every size and shape have been steadily upgrading wireless equipment especially now that security and ease of use/installation issues have been strengthened. Widespread use of the 802.11n standard for wireless LANs is helping enterprises meet user density demands, boost performance significantly, and deliver wireless coverage over previously inconceivable ranges. This white paper explores 802.11n technology and applications, while offering business leaders a solid educational foundation for making wireless deployment and purchasing decisions.

Mobility, User Density, Performance, Convergence and Cost Issues Drive Demand for Better Wi-Fi As more people with Wi-Fi devices descend on company networks, enterprises need to enhance or upgrade their wireless LANs. Remote employees need to stay connected to corporate networks. Users want to be able to roam around an office or campus without being tethered to Ethernet jacks. Fortunately, rapid advances in wireless technology have boosted performance, as well as security and ease- of-use features. Video, podcasting, rich Internet applications (RIA), video conferencing (even in HD), VoIP, Web 2.0 apps and the general trend toward Web applications have all been placing pressure on networks wired and unwired. If you consider video alone, the bandwidth challenges are glaringly obvious. Everyone with a laptop, netbook, gaming device, cell phone, dual mode phone or other such device essentially has a TV in their pocket sucking up extraordinary amounts of bandwith. Companies are also producing significantly more video and audio for their Web sites. Web 2.0 is as much about video (YouTube, Seesmic, etc.) as it is about social networking. Employee tutorials, product pitches, trade show demos, and keynote presentations are all either streaming or archiving across the Web. While the proliferation of wireless networks, devices and bandwidth applications may be unstoppable, companies can easily adjust infrastructures to relieve bandwidth crowding and user density issues. New 802.11n wireless access points and unified switches feature technologies that allow radio signals to travel faster and further and for a larger number of users than with previous 802.11a/b/g equipment. The equipment is especially helpful where companies make use of Virtual Private Networks (VPNs). VPN encryption adds significant overhead to data channels, but newer, faster, farther-reaching wireless technology lessens that additional burden. It should also be noted that 802.11n equipment can be deployed to cut costs. As the range and speed you gain by deploying 802.11n increase, the number of APs required to cover specific areas of your premises is reduced. The new APs increase the number of concurrent users able to access the network, as well. Couple this with the productivity gains associated with improved connectivity, faster connections and more rapid file transfers, and you have a recipe for considerable cost savings. Wireless Infrastructure Upgrade Drivers Complex, mission-critical applications are moving to the Web A growing number of devices depend on wireless access Voice-over-WLAN (VoWLAN) and dual-mode phones require guaranteed bandwidth and high Quality of Service (QoS) Wireless IP Surveillance requires guaranteed bandwidth and substantial security Voice, data and video convergence Video conferencing and video consumption are on the rise More real-time financial and ordering transactions are occurring over wireless networks Challenging RF environments (factories, warehouses, urban centers) demand better wireless coverage What is 802.11n? Technology Overview IEEE 802.11n is an amendment to the IEEE 802.11-2007 wireless networking standard. The new standard improves network throughput speeds and distances set by previous standards like 802.11b and 802.11g. Technologies based on 802.11n increase maximum raw (PHY) data rates from 54 Mbps to a maximum of 600 Mbps (with dual-band, 2.4-GHz and 5-GHz radios). Current equipment supports PHY rates of 300 Mbps by using two spatial streams at a channel width of 40 MHz (channel bonding). Even though final 802.11n draft approval is expected in Jan 2010 (IEEE), many Draft N products are already available. D-Link has more than 20 SKUs supporting 802.11n. 802.11n enhances earlier standards by adding multiple-input multiple-output (MIMO) and channel bonding/40 MHz operation to the physical (PHY) layer. It also adds frame aggregation at the MAC layer. With MIMO, multiple transmitter and receiver antennas improve system performance over single and double antenna systems. MIMO essentially processes more information. The technology takes multipath signals that arrive at the receiver after line of sight signals have been received. In contrast, non- MIMO 802.11a/b/g networks would perceive multipath signals as interference, which would hinder the receiver s ability to recover message information in the signal. MIMO, on the other hand, uses the multipath signal diversity to improve the receiver s ability to gather message information. MIMO uses Spatial Division Multiplexing (SDM) to combine multiple independent data streams that are transferred simultaneously within one spectral channel of bandwidth. Individual antennae on the transmitter and receiver manage each spatial stream. As the number of spatial data streams is increased, MIMO SDM significantly increases data throughput. Channel bonding, or 40 MHz, transmits data over two separate, non-overlapping channels, thus increasing the amount of data that can be transmitted. The term channel bonding is used because two adjacent 20 MHz bands are bonded as if on a single 40 MHz channel. This effectively doubles the PHY data rate from a single 20 MHz channel. 2

Improved Link Predictability and Reliability 802.11n improves link reliability and predictability, thus enhancing application performance. The MIMO signal processing discussed earlier improves the reliability of wireless links and decreases packet loss. Consistent throughput and less dropped packets enables coverage reliability across the installation. MIMO advantages are evident at both the client and the access point, because it reduces the effects of interference created by building materials, dead zones, and multipath propagation. Backward Compatibility 802.11n/g/a/b Maximum performance for 802.11n benefits significantly when using the 5 GHz band setting (although most 802.11n equipment can work on either 2.4 GHz or 5 GHz bands). Since the 5 GHz band does not have the overlapping radio channels and abundant radio interference that the crowded 2.4 GHz band suffers from, the band is much more robust and clean. In many cases however, enterprises maintain a fair number of 802.11g, and even 802.11b equipment (802.11a operates in the 5 GHz band). In this case, replacing Wi- Fi cards for every client installation may be less than practical. Fortunately, it is easy to maintain a mixed 802.11b/g/n network and adds 802.11n hardware upgrades over time. In this type of scenario, a dual-band set-up is optimal, with 802.11b/g traffic on the 2.4 GHz radio and the 802.11n (and 802.11a) traffic on the 5 GHz radio. Glossary Common Terms and Acronyms LAN - A local area network (LAN) is a computer network covering a small physical area, like a home, office, or small group of buildings, such as a school, or an airport. The defining characteristics of LANs, in contrast to wide-area networks (WANs), include their usually higher data-transfer rates, smaller geographic range, and lack of a need for leased telecommunication lines. WLAN - A wireless LAN (shortly WLAN) is a wireless local area network that links two or more computers or devices to enable wireless communication between devices in a limited area. This gives users the mobility to move around within a broad coverage area and still maintain connection to the network. Wi-Fi - A trademark of the Wi-Fi Alliance, founded in 1999, based on the IEEE 802.11 standards (also called Wireless LAN [WLAN] and Wi-Fi). This certification warrants interoperability between different wireless devices. The term is also used interchangeably with Wireless LAN or Wireless Networks that comply with IEEE 802.11 specifications. IEEE 802. Standards - A family of IEEE standards dealing with local area networks and metropolitan area networks. WDS (Wireless Distribution System) A system that enables the wireless interconnection of access points in an IEEE 802.11 network. It allows a wireless network to be expanded using multiple access points without the need for a wired backbone to link them, as is traditionally required. The notable advantage of WDS over other solutions is that it preserves the MAC addresses of client packets across links between access points. WME - Wireless Multimedia Extensions, also known as Wi-Fi Multimedia (WMM) is a Wi-Fi Alliance interoperability certification, based on the IEEE 802.11e draft standard. It provides basic Quality of service (QoS) features to IEEE 802.11 networks. WMM prioritizes traffic according to four Access Categories (AC) - voice, video, best effort, and background. However, it does not provide guaranteed throughput. It is suitable for simple applications that require QoS, such as Voice over IP (VoIP) on Wi-Fi phones. MIMO (multiple-input and multiple-output) Radio technology that uses multiple antennas at both the transmitter and receiver to improve communication performance. MIMO has attracted attention in wireless communications, since it offers significant increases in data throughput and link range without additional bandwidth or transmit power. It achieves this by higher spectral efficiency (more bits per second per hertz of bandwidth) and link reliability or diversity (reduced fading). Multiplexing Combining many signals into a single transmission circuit or channel Source: Wikipedia 11N Advantages What the Technology Leap Means to Users and Enterprises Most companies will migrate to 802.11n to gain performance improvements that enable higher user densities, dramatically better video streaming, improved mobile connectivity, and all the flexibility that comes with untethered, high-bandwidth connections. The current PHY rates of 300 Mbps translate to roughly 185 Mbps in real world environments. In many cases, that can translate into performance that competes with wired 100Mbps connections. Companies are now producing volumes of videos for internal and external consumption, many in high definition (HD) format, which requires 802.11n bandwidth levels for latency-free play. These include training videos, marketing information, social advertisements designed for YouTube, presentations, webcasts, product demonstrations and more. According to techcrunchies.com, videos account for 30 percent of internet traffic. By 2010, they will account for 80 percent of all traffic. Also, High-Definition video will become the order of the day, and HD videos are seven to ten times more bandwidth-hungry. (Source: http://techcrunchies.com/what- percentage-of-internet-traffic-is-video/). 3

The numbers from YouTube alone are staggering. The popular video site has 100 million visitors every month and streams 40% of all online videos (that s 5 billion video streams per month). This amounts to 17 streams per person per month. Fifteen hours of video are uploaded to YouTube every minute. (Source: http://blog. cleancutmedia.com/video/youtube-statistics-the-ultimate-time- suck). Roughly 20% of the videos are professional or commercial in nature (Source: http://ksudigg.wetpaint.com/page/youtube+statisti cs?t=anon). Rich mobile applications for wireless devices will also require more and more wireless bandwidth. Organizations that act quickly to build out their 802.11n networks will be in a better position to leverage these applications; connect with customers, prospects and the public; and drive value in the wireless information channel. Simple employee productivity and efficiency gains alone should more than cover costs. Enterprise-level 802.11n equipment does not require a major capital outlay. and CT scans are often 6-10 megabytes or more in size. Passing these around with any kind of efficiency on a legacy a/b/g network is simply impractical. 802.11n solves this issue, delivering very large files in a fraction of the time. Even dental offices are taking advantage of the technology. Offices with 802.11n access points can deliver tooth x-rays from the office server to a screen at the patient s chair in just seconds. There s no developing, printing and walking film around the office. These offices save time as well as supply costs. Educational institutions across the world are now installing sophisticated wireless networks to meet Web-savvy student demands. They offer wireless connectivity to every nook and cranny of sprawling campuses, and they also install IP cameras for monitoring public areas and preventing crime. Students tend to be heavy consumers of video, audio and similar high-bandwidth instructional materials, so 802.11n is ideal for their mobile orientation. Government organizations are also getting in on the act. 802.11n helps them save money when architecting municipal wireless projects, covering large areas with IP surveillance equipment (without running cable), and offering the public Internet access at libraries, court houses, community centers and other similar venues. ABI Research expects 802.11n access point shipments to take off over the next five years. The Ideal Solution for Government, Education and Health Care Verticals While 802.11n originally caught on with home power users and small businesses that needed to move large data files, graphic files, movies and audio across wireless home or office networks, new business equipment is fueling 802.11n adoption among enterprises and larger companies. This is especially true in the health care, education and government verticals. Medical providers, for example, are becoming more and more technology-focused. In order to improve office efficiency and deliver critical medical images and documents to key decision makers, medical practitioners need large local network pipes. High-resolution medical images like x-rays, MRIs, Ultrasound videos New IP Hardware, Gadgets, Phones and Cameras Need More Juice New VoIP business phone systems, video conferencing equipment and IP surveillance systems are also poised to leverage wireless networks. For example, dual-mode wireless phones that utilize VoIP systems require robust wireless coverage to reduce latency issues and ensure high quality calls. These phones also need a wireless network that can handle AP to AP hand offs for roaming around the premises. 802.11n delivers on all counts. In addition, with 802.11n, video conferencing systems do not have to be relegated to a hardwired conference room, and IP surveillance cameras can be placed anywhere power outlets exist. Why multimedia applications and latency intolerant applications cannot operate effectively on legacy networks: MPEG 2 HDTV 1080i - 19 to 20 Mbps for a channel WM 9* and MPEG 4-8 Mbps per single stream Microsoft Media Center standard TV stream 8 to 10 Mbps per stream Video Gaming 10 Mbps per console VoIP calls 1 Mbps Audio files/mp3 2 Mbps Digital photography 1+ Mbps Multiple activities with any of these types of media will quickly bring down a 54 Mbps network. (A 54 Mbps physical rate translates into 24 Mbps of actual end-user throughput). Source: Atheros Communications 4

More Users and Devices Require More Connections The number of network-connected devices and users is growing rampantly, so wireless networking will be in a constant race to keep up from here on out. Most people carry multiple devices (one or more of the following - two-way phones, laptops, netbooks, music players, digital cameras, gaming consoles, and so forth). Many of these devices will be Wi-Fi enabled in the near future if they re not already. People have been slowly trained to find Wi-Fi networks, as well. They re using tools like NetStumbler and WeFi to track down wireless networks, for example. Most wireless users have Googled for free hotspots in their area, and most of us have used a Starbucks hotspot at one time or another. All this wireless activity ultimately drives the need for more connectivity and higher density deployments at work and out in the retail world. People just expect a signal. This is particularly true for venues where people gather in large numbers like corporate campuses, schools, malls and airports. Specific verticals like government, education, healthcare/medical, hospitality (hotels, spas), and transportation are natural fits for upgrading to 802.11n. And, as we mentioned earlier, 802.11n can handle more VPN tunnels, so enterprises that need better VPN performance are definitely taking note. Q &A How is bandwidth and reach impacted in mixed a/b/g/n environments? 802.11n networks and clients maintain faster performance rates, even alongside slower 802.11a/b/g equipment. In these types of mixed-mode scenarios, aggregate performance is slower than a pure 802.11n environment, of course. However, the overall throughput exceeds the slowest legacy standard. There are several factors to consider when evaluating your particular situation and performance variance: 802.11n APs coupled with 11n devices will transmit at 11n rates, even in the presence of legacy devices. If you use 5-GHz devices (including legacy 802.11a equipment and new 802.11n equipment) as opposed to 2.4-GHz devices, your aggregate performance will improve. As more 11n devices come online, aggregate performance will improve. 802.11g deployments demonstrated this as they gained traction in the market. This should happen even faster with 802.11n. More laptops are now shipping with 11n support, for example. What s the best strategy for enabling larger user densities? The ideal scenario for boosting network speeds and extending radio reach is to deploy 802.11n access points and client adapters. For full benefits, it is recommended to replace 802.11a/b/g access points one-for-one with 802.11n equipment for optimal user density and bandwidth performance. You will, however, see throughput and range improvements in mixed environments, as well. Why not wait for 802.11n ratification? 802.11n equipment is ready for deployment right now, and it works well with existing a/b/g networks. Industry experts don t expect the existing draft to change significantly, and they are confident that firmware updates will cover the eventual ratified 802.11n specifications. In other words, you ll be able to keep draft-n products compatible with the new draft through a firmware upgrade (if that s even necessary the draft may stay the same as it exists today). If 3-10 Mbps download speeds are common with Cable, DSL, fiber and T1 connections, why would we need more than the 54 Mbps a 802.11g router provides? A 54 Mbps router or access point provides more than enough bandwidth to support web browsing, email and average-sized data transfers for networks with a limited number of wireless clients. Consider, however, that the 54 Mbps physical rate translates into 24 Mbps of actual end-user throughput. This bandwidth cannot handle simultaneous high-bandwidth activities like streaming video transmissions and multiple VoIP calls on the local network. Understand that the bandwidth refers to total throughput to all connected clients and not to bandwidth per connected clients. Also, legacy equipment offers decent coverage but fails approach the range supported by 802.11n. Can 802.11n handle HD video conferencing feeds and HD video sharing? Yes. Multicast HDTV streams have been well documented with consumer home 802.11n networks. The same results apply to enterprises and workplaces. With the appropriate inbound WAN connection, HD video conferencing feeds can also be shared across the local 802.11n network with ease. 802.11n Ratification Status The current 802.11n standard is in draft status. This means that more specifications will be considered before the standard is finalized and ratified. That said, all parties involved with the draft consider it very stable and expect only minor changes moving forward. According to D-Link partner Atheros (a major 802.11n chipset manufacturer), It is highly likely that there will be few differences between product based on the 2.0 draft of the specification and the final 802.11n specification. In fact, given the maturity of the 2.0 draft, it is expected that changes which occur in the 3.0 draft can be made in draft 2.0 end-products with firmware (software) upgrades. See Figure 1 for Ratification timeline. 5

Figure 1: Ratification Timeline Source: Atheros In mid-2007, the Wi-Fi Alliance started certifying products based on IEEE 802.11n Draft 2.0. These are the draft n products mentioned earlier. This baseline certification covers both 20 MHz and 40 MHz wide channels, and up to two spatial streams, for maximum throughputs of 144.4 Mbps for 20 MHz and 300 Mbps for 40 MHz. A number of vendors in both the consumer and enterprise spaces have built products that have achieved this certification. (Source: Wikipedia) D-Link 802.11n Solutions D-Link is one of the leading innovators in 802.11n hardware with more than 20 SKUs for 802.11n equipment and has achieved numerous awards from industry reviews. We were the first company to offer green routers and switches that provide eco- friendly hardware alternatives without compromising performance. Our customers wanted to wirelessly share USB devices like printers and storage over their networks, so we introduced SharePort technology, which was also an industry first. We were also one of the first companies to introduce SMB Routers with QoS. We re now building on that previous track record with business- class 802.11n APs, APs with plenum rated chassis, wireless controllers and a comprehensive AP management solution called AP Manager II (more on this last product below). D-Link wireless switching solutions include rogue AP detection which helps administrators easily detect and block unauthorized access points that are attempting authentication on the network. Our 802.11n access points also require much less daisy-chaining, because their ranges extend so far. Daisy chaining introduces noise and interference into the air waves. With D-Link 802.11n, you position access points much further apart while connecting far more clients than with legacy equipment. 600 550 500 450 400 350 300 250 200 150 100 50 0 129.9 D-Link Linksys Netgear 365.6 Q4/06 Units 109.2 210.2 324.7 Q1/07 Units 142.8 321.7 Q2/07 Units What follows are some specifications from just a few of our 802.11n offerings (including AP Manager II 441.5 112.4 440.3 459.8 Q3/07 Units 182.1 584 566 Q4/07 Units 293 Source: On-State 2Q 2007 Over the past three years, D-Link has become the leader in 802.11n sales due to our technology leadership and reliable designs. 6

. DAP-2553 Air Premier N Dual Band PoE Access Point Features: User-Selectable 2.4GHz or 5GHz Frequency Band Operation for Increased Network Capacity 802.3af PoE Support 3 Dipole Antennas to Boost Signal Strength Operable as Wireless Client, Access Point (Wireless Connectivity for Computers), WDS (Wireless Bridge), or WDS with AP Multiple SSID, 802.1Q VLAN WMM (Wireless QoS) Automatic Channel Selection DAP-2590 Air Premier N Dual Band PoE Access Point with Plenum-rated Chassis Features: User-Selectable 2.4GHz or 5GHz Dual Band Draft 802.11n Wireless Connectivity for Business-Class Environments Operable as Wireless Client, Access Point, Wireless Bridge (WDS), or WDS with AP Supports Wi-Fi Multimedia (WMM) QoS Features for Enhanced Performance Supports WPA/WPA2-Personal and WPA/ WPA2-Enterprise Security Features Ideal for Indoor Deployments Plenum-Rated Chassis Designed to Adhere to Building Regulations Advanced Management Options Including AP Manager II, SNMPv3, Secure Telnet, Secure Shell (SSH) and Secure HTTP (HTTPS) Soon available will be the DAP-3520. This is also an AirPremier N Dual Band PoE Access Point, with features similar to the DAP-2553 and DAP-2590. However, the DAP-3520 is designed for exterior deployments in support of small and medium business- class environments or enterprise corporations to provide secure and manageable dual band wireless LAN options for network administrators. D-Link s Free 802.11n Management Solution AP Manager II D-Link AP Manager II helps IT managers realize the benefits of Wireless networking technology without the headaches of decentralized, changing Wi-Fi configurations. The software comes free with D-Link APs and allows you to easily manage a broad mix of access points from one computer across multiple subnet boundaries. With AP Manager II, you can conduct regular maintenance checks without wasting resources by sending personnel out to physically verify each access point. The software is built with a robust SQL database, so it can easily manage hundreds of APs. A Single Centralized Management Solution AP Manager II provides a centralized, Web-based management interface for supporting all APs across a WLAN. The administrator logs in to a PC and all the options are available to manage the access points by IP Address, model name, location or MAC address. With AP Manager II, you can conduct regular maintenance checks without wasting resources by sending personnel out to physically verify each access point. The software is highly scalable and is built with a robust SQL database, so it can easily manage hundreds of APs. The software enables group and multi-configuration management, which allows you to upgrade firmware across all APs via templates designed for specific groups. Maintenance templates can also be applied to groups via template. As a result, you spend less time and resources manually updating APs one-by-one. Deploy 802.11n Now to Reduce Costs, Boost Performance and Extend Range D-Link 802.11n wireless solutions are ready to deploy for all kinds of businesses. Whether you re interested in scaling an existing network, saving money while adding users, or making productivity gains over older, sluggish equipment, we can help. Our latest equipment is the most enterprise IT and home-user friendly ever. The solutions are easy to install, maintain and use, even when you re managing large deployments with dozens of access points. The demand for enterprise wireless is hitting an all-time peak right now. And, as more and more users expect to access video, applications and data wirelessly with a wide range of devices, that demand is only going to increase. Now is the time to start seriously considering 802.11n solutions. For more information on D-Link 802.11n technologies and equipment, please call us at 1-800-326-1688 or visit www.dlink.com. Maximum wireless signal rate derived from IEEE Standard 802.11g and draft 802.11n specifications. Actual data throughput will vary. Network conditions and environmental factors, including volume of network traffic, buildings materials and construction, and network overhead, lower actual data throughput rate. Environmental factors will adversely affect wireless signal range. Wireless range and speed rates are D-Link RELATIVE performance measurements based on the wireless range and speed rates of a standard Wireless G product from D-Link. Maximum throughput based on D-Link draft 802.11n devices. D-Link and the D-Link logo are trademarks or registered trademarks of D-Link Corporation or its subsidiaries in the United States and other countries. All other trademarks or registered trademarks are the property of their respective owners. Copyright 2009 D-Link Corporation/D-Link Systems, Inc. All Rights Reserved. 7