Some existing wireless LANs, based on 802.11abg gear, already "are buckling under video applications," says Andrew Borg, senior research analyst for wireless and mobility at Aberdeen Group, a technology research and consulting firm based in Boston. And the surge in sophisticated mobile devices is making it worse.
In higher education, Borg says, those applications include distance learning, online collaboration and social media; in healthcare, remote medicine and large diagnostic imaging; in physical security, video surveillance; and in offices, media streaming, videoconferencing, online meetings and more.
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The demand increases even more with smartphones and tablets that have Web access and a growing appetite for video. The iPhone 4's FaceTime application, for video chatting over Wi-Fi, is just the most recent and most notable bandwidth-hungry mobile application.
"With the enabling of more mobile multimedia content, my customers' concern is being able to increase network capacity, both technically and economically, to meet demand," says Brad Noblet, a wireless consultant. "Network administrators worry they are fast becoming a public utility for employees and not serving their institution's mission."
Noblet has specialized in scaling WLANs to support growing numbers of users and mobile clients, and soaring traffic volumes, especially in streaming audio and video calling. Part of the solution is the technology underpinnings: there's a big shift now toward deploying 802.11n, with access points that can support throughput of 100Mbps or more, the use of the 5GHz band, and 40MHz-wide channels. But a lot of analysts and IT professionals agree that 11n, by itself, is not the answer to growing demand.
"It's something that users need to consider when shopping for a new WLAN, and [make it] a big part of the request for proposals and subsequent discussions with vendors," says Craig Mathias, of the Farpoint Group mobile consultancy. Initial WLAN planning, for new or upgraded networks, should be future-oriented, "with an eye towards growth in users, applications, data object size, and requirements for time-bounded traffic," he says.
Sometimes, scaling problems are caused by back-end systems, such as RADIUS and DHCP servers, that are not set up to handle lots of mobile users and devices, according to Noblet. "Good routing, protocol throttling, and fat backhaul are the only keys," says ExtremeLabs Managing Director Tom Henderson. "Unless you shoot the users."
Some WLAN vendors can do traffic forwarding at the access point, rather than physically routing every packet through a centralized WLAN controller, notes Rohit Mehra, director of enterprise data communications infrastructure at IDC, a technology research firm.
Layering vendor- or third-party network and RF management applications, and tools to improve client performance, on top of the WLAN make it possible to set and enforce a range of administrative controls: allocating bandwidth and prioritizing traffic by protocol or user are examples, Mehra says.
Device management and security applications can let you set policies for the devices and applications accessing the company network. A company may create a white list of permitted applications, or a black list of banned ones, such as YouTube, Skype, "or other high-bandwidth personal applications," says Khoi Nguyen, group product manager for Symantec's mobile security group. Some policies may be applied or not depending on whether the phone is roaming. These kinds of fine-grained controls are starting to become more common in device management applications, he says.
John Cox covers wireless networking and mobile computing for "Network World."
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