Are we near the point where wireless networks can replace good, old Ethernet? A new report from The Burton Group answers that question in the affirmative, saying that the increased speeds and other features of 802.11n should be enough for many companies to cut the wires on their WANs in the next two to three years.
While 802.11n speeds still fall far short of those of gigabit Ethernet, Burton believes that they should be good enough for most uses. In fact, in its list of recommendations on when to deploy 802.11n, one of the criteria listed is "when fast Ethernet [100Mbps] throughput is good enough."
The report supports that assertion by calculating (but not testing) download times over 802.11g, 802.11n, fast Ethernet, and gigabit Ethernet. With a 2MB file, the difference will be negligible for everything but 802.11g, which will take 5 seconds. Downloading an 8MB file over 802.11n should take about 4 seconds if there are 10 users on a given access point, compared to less than a second for both fast and gigabit Ethernet. "Even with 20 users per AP, the file download times ranged from two to eight seconds—still satisfactory for most users," notes the report. These numbers are theoretical, so sprinkle with NaCl as necessary, but they do show that 802.11n speed should be good enough in many cases.
With many companies switching to VoIP for voice traffic, the other big factor is how well 802.11n can handle voice traffic, especially with 10 to 15 users on a single access point. The Burton Group believes that 802.11n will be up to the task. Although latency is up to 20 times higher than that of gigabit Ethernet, the difference will not be enough to impact VoIP. The same can be said of jitter, the amount of variation in the arrival times of VoIP packets. "Jitter can be as high as 150 times that of gigabit Ethernet," notes the report. "But who cares? Again, the difference will have little impact on jitter-sensitive applications such as VoWLAN [voice over WLAN] because the absolute value is so small compared to the VoWLAN jitter budget."
The other major factor in adopting 802.11n is the increased prevalence of laptops in the enterprise. Deploying 802.11n allows companies to meet the needs of a mobile workforce, argues the report, and makes moves, adds, and changes a much simpler process if the employee in question has a laptop and uses VoiP.
There's one red flag: security. The report's authors note that using a WAP is the equivalent of "having an RJ-45 jack in the parking lot." It's much easier for the riff-raff to discover, attach to, and attack a wireless network than it is a wired network. And as anyone who has followed wireless security over the years knows, the use of WiFi opens up a whole new can of worms when it comes to network security. The report argues that most of those risks can be mitigated. "[A]n 802.11n network can be made almost as secure as Ethernet, but that security will come at a greater cost than for a wired Ethernet network."
Reality check
Corporate IT departments are seldom quick to rush headlong into new technologies, though, and 802.11n should be no different. Although 802.11n has reached a stable stage in its development with the release of Draft 2.0 equipment that will be easily upgradable to the final spec, it's still not a tried-and-tested solution, especially in the enterprise. And although it's hard not to buy a new laptop with 802.11n support, corporate purchase cycles are such that there will be a number of laptops still using 802.11g for some time to come—and they'll be left out of the 802.11n lovin'.
Although our recent testing found that some of the current hardware doesn't live up to our expectations, performance should improve as we move towards the official 802.11n spec. Even now, WAPs that support 5.0GHz, 802.11n-only modes appear to offer better throughput than those operating in backwards-compatibility mode.
The Burton Group believes that the end is in sight for Ethernet "as the dominant local area network access technology in the enterprise." That may be a bit of an overstatement, as some applications will continue to demand the high speeds that only a wired, gigabit Ethernet network can provide. And although security on 802.11n may be "almost" as good as wired networks, almost won't be good enough for some companies. In some cases, there's no substitute for good old Cat 5e or Cat 6 cable, and we don't see our near-future being as wireless as Burton predicts.
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