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Infrastructure Cutting the cord Now that 802.11ac is speeding up wireless networking, do we still need Ethernet? Danny Bradbury finds out. by Danny Bradbury, freelance technology journalist W e’ve come a long way since we first cut the cord. The first commercially useful Wi-Fi standards were ratified in 1999, and enabled a generation of users to roam around the office - but few of them did it all the time. Often, people working in businesses still clung to wired Ethernet as a way to connect devices that needed reliable, fast network traffic. Now, with a new generation of Wi-Fi standard in play, that may be changing. Wi-Fi communication speeds were still slow at the beginning, with 11Mbits/sec the norm. Speeds increased, but so did the bandwidth requirements in the average office, as IP telephony and video applications flourished. Wi-Fi worked, mostly, for watching YouTube videos at lunch, but if you really wanted to be sure that your VOIP call went through, wired Ethernet was the way to go. In late 2013, 802.11ac revolutionised the Wi-Fi space. It operates on the 5GHz band, rather than on the 2.4GHz spectrum that has been so heavily used by prior Wi-Fi standards like 802.11a, and its high-speed predecessor 802.11n (which could operate on both). The other benefit of 802.11ac is that it uses wider ‘channels’ (windows of radio spectrum that access points and clients can connect through). It uses 80MHz compared to 802.11n’s 40MHz, effectively doubling the amount of data that can be pushed through a single channel. These enhancements are complemented by better compression, and technology to prioritise traffic, which will please users of low-latency applications such as IP telephony. They push the theoretical limit of 802.11ac to multiple Gigabits per second, but in practice, as with all theoretical estimates targeting perfect physical environments, the reality is far slower - around 400- 800Mbit/sec, say. Still, this development has led Gartner to predict that by 2018, 40% of enterprises will specify Wi-Fi as the default connection for non-mobile devices. That’s possible, as long as you’re happy with speeds like that to do the desktop, but it will require some forethought and work. Distance from the router is one consideration, said Dr. Kevin Curran, senior member of the IEEE, which defines these wireless standards. Higher-frequency communications systems like 802.11ac have a shorter reach, meaning that if a client device is too far from a wireless ac router, it will fall back to 802.11n, removing much of that benefit. “If you’re right beside your router in the same room or near, then I’d recommend AC because it’ll be faster,” he said. “But if you’re on the edge of a large building then you’re unlikely to get the connection with 8022.11ac. It’s a distance thing, really. It depends how far away you are.” In that sense, you can’t just rip and replace wired with wireless - you may have to redesign the LAN to accommodate the various nooks and crannies of the office. The other issue is the uplink. Wi-Fi access points still have to connect to the corporate network via an Ethernet uplink. Using a wireless access point serving 802.11ac devices as the sole connectivity hub will burden its uplink with more bandwidth. That will require some rethinking of the back-end network architecture, and potentially some expensive upgrades, as Irwin Lazar, vice president at analyst firm Nemertes Research, points out. And if you’re currently using deskphones powered via Ethernet, removing that link will present some redesign issues. By all means experiment with moving completely to wireless operations, but be prepared for the hidden complexities. It won’t be an easy ride. 46 Probrand Group Magazine Probrand Group Magazine