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FCW : September 15, 2013
39 CDWG.com | 800.808.4239 Best Practices in Implementing Wireless Networks Building wireless networks requires blending systems engineering --- properly tuning radio frequency, for instance --- with hard-earned knowledge. Although there are many ways to configure and use Wi-Fi, best-in-class organizations should apply these strategies to get the most out of their networks: Practice active management: Wi-Fi networks don't stay in top condition on their own. Good network management practices, including the regular scanning of logs and the active monitoring of devices and usage, will help identify problems before they affect performance. Use managed wireless products: When considering wireless management, the network team should be careful to distinguish between fully managed solutions and those that only offer configuration control and log collection. Simply capturing the configurations of each AP and pushing changes to them uniformly is not true wireless management. Any deployment with more than eight APs will need a fully managed solution. Prioritize usage: A wireless network can reach near capacity even when no one is actively using it. e solution isn't to prohibit casual use, but simply to make sure that mission-critical applications, such as VoIP (unified communications) or transaction processing, and professional uses get priority over nonprofessional or casual usage. By using management configuration, firewalls or Wi-Fi Multimedia (WMM), it's possible to throttle bandwidth. Develop a guest policy carefully: Accommodating guest access to wireless networks is generally considered a requirement for enterprise wireless installations. Any guest policy must balance its requirements for accountability and prevention of "drive-by" connections with the goal of making guest connections simple and quick. Many vendors offer specific guest services, such as captive portals and automated guest provisioning systems that can ease the task of offering guests wireless connectivity. Build security from the start: Many techniques exist to increase overall security for wireless users, but involving security teams from the beginning will make it possible to incorporate key requirements into the architecture design and product selection phases of the project. Optimizing Network Performance with 802.11n Anyone currently considering creation of an enterprise-class wireless infrastructure should be sure to focus on 802.11n and eliminate any pre- 802.11n equipment from the network in order to exceed speeds far above the old 54Mbps. e following strategies can be used to optimize performance of networks based on 802.11n: FOCUS PRIMARILY ON 5GHZ 802.11A BANDS: Legacy wireless equipment often uses the 802.11b/g band, but it can be difficult to get good network performance in that band when 802.11n is deployed. For best performance, devices should employ the 5GHz band whenever possible to ensure that the higher-capacity 40MHz channels can be used and that more devices can share the radio- frequency space in a smaller physical area. USE 802.11N 3X3:3 ACCESS POINTS WHENEVER POSSIBLE: Newer devices and APs coming on the market have three streams across three antennas (3x3:3). ese have a top speed of 195Mbps, or 405Mbps with double-wide channels. e longevity required of APs makes it worthwhile to purchase devices that will extend an organization's refresh cycle. TURN THE POWER DOWN: Wireless devices must share the same radio- frequency space. Additional power simply creates noise and performance slowdowns for adjacent devices and APs. A maximum power level of 50MW or lower will yield better network performance. If users report poor signal strength, the first solution should be to add another access point rather than turning up wireless power. BLOCK LOW SPEED ACCESS: Enterprise networks should block clients from connecting at low data rates by increasing the data rate use for beacon frames (the 10-times-a-second frame that every AP emits to announce its capabilities) as well as the minimum connection speed allowed. e default should be raised above not only the commonly used 1Mbps and 2Mbps, but also over the old 802.11b rate of 11Mbps. is adjustment will have the desired effect of blocking old 802.11b devices from connecting to the network and causing performance problems. Networks that have multicast applications, such as multicast video, should have their minimum data rates increased as well, but will require more sensitive tuning.
August 30, 2013
September 30, 2013