Appallingly slow speeds, dropped connections, and routers that are working fine one minute and apparently drop off the face of the Earth the next – anyone who has ever set up a Wi-Fi network will have battled with these problems.
Despite huge advances in speed and range, Wi-Fi remains one of the most unreliable everyday technologies, according to industry experts. For many Australian ISPs, complaints over Wi-Fi drop outs, or even the initial set up of a wireless router, form a large amount of their day-to-day service calls.
What's in this feature:
The Wi-Fi killers – the wrong choice of security protocol, or the gadget installed in next door’s lounge.
How to diagnose and fix the problems you encounter on your wireless network, find interference on your network, extend its range and speed.
List of Wi-Fi and its various standards, how bands and channels actually operate.
The Wi-Fi Killers
What’s the number one threat to the smooth running of your Wi-Fi network? Interference, and plenty of it. It isn’t only interference from neighbouring networks that you have to worry about – indeed, some experts suggest conflicting Wi-Fi traffic is relatively harmless – but all manner of electrical devices inside and outside of your premises (see below).
The sheer ubiquity of wireless networks is staggering. Walking around the block from the PC & Tech Authority offices, we can detect no fewer than 14 Wi-Fi networks (both business and domestic) fighting for attention in the 2.4GHz band. That’s only the 802.11 networks; anything from wireless security cameras to Bluetooth headsets, to the microwave in the office kitchen may also be operating in that unlicensed spectrum or creating interference.
Not only do the majority of homes and businesses now operate Wi-Fi networks, but they’re also increasingly likely to be using 802.11n equipment, which offers a far greater range than previous generation 802.11abg networks.
With an indoor range of up to 70m and the ability to pass through multiple brick walls, there’s every chance that the router from next-door-but-one is sharing the same airspace as yours, whereas that simply wouldn’t have been the case even two years ago. In flats or apartments, where the signal comes from all sides, the problem is multiplied.
The congestion is exacerbated by standard router setups that often leave neighbours sharing the same Wi-Fi channel. “A lot of [Wi-Fi router] manufacturers have a default Wi-Fi channel. Many choose channel 6,” said Roger Tao, strategic technology product manager at the European arm of D-Link, creator of the Boxee Box hardware. Indeed, 5 of the 14 Wi-Fi networks accessible from our offices were fighting for space on the same channel.
With Australian ISPs handing out hundreds of thousands of the similar routers to their customers, you’ll often find clusters of routers sharing the same channel. And if you buy your router from a standard electronics store, it’s not likely to be too different. Some of the newer crop of more modern routers get around this by automatically scanning for the least congested Wi-Fi channel available, but for those of us still using slightly older gear - or just using what was supplied to us via our ISP - this clash of the channels can be a major contributor to Wi-Fi slowdown and drop outs.
Too many cooks
With Wi-Fi traffic reaching rush-hour M5 motorway levels in urban areas, some people are tempted to cheat. By downloading an American or Asian version of your router’s firmware – or even changing the location settings in the current firmware – it’s often possible to unlock the 14th Wi-Fi channel in the 2.4GHz spectrum. As we explained earlier, this is technically illegal because it creeps outside of the unlicensed spectrum: 2.4000-2.4835GHz is the allocated spectrum, while channel 14 operates at 2.484GHz.
While some people might be tempted to bend the rules to avoid Wi-Fi channel congestion switching your router to channel 14 isn’t necessarily a panacea: some client devices simply refuse to operate on channel 14.
Another commonly used tactic to overcome interference is to increase the number of access points, especially in business premises. Yet, according to a Cisco white paper “20 Myths of Wi-Fi Interference”, a Cisco white paper, this can often make matters worse. “Some networks are being deployed with an AP in every room,” the paper states. “It seems intuitive that by having more APs spread around, it’s more likely that a client will be able to operate successfully even when interference is present.
“Unfortunately, when you deploy a dense network of access points, it’s necessary to reduce the transmit signal power of each of the access points. If you don’t reduce the power, the access points generate interference to each other, a phenomenon known as co-channel interference. The reduction in the transmit power of the access point exactly offsets the potential benefit of interference immunity. So, in the end, the interference immunity of a network with a dense deployment of access points isn’t significantly better than that of a less dense deployment.”
In fact, although overlapping networks and co-channel interference can undoubtedly harm the performance of your Wi-Fi devices, it’s more likely that other forms of RF interference are doing more damage to your speeds than the router next door.
It must be noted that lots of Wi-Fi networks doesn’t necessarily mean you’re going to have a problem. In fact, many Wi-Fi networks can quite happily co-exist side-by-side. It’s the ones that can’t that create all the issues.
Roger Tao agrees, explaining that routers are designed to cope in regions with a far higher population density than seen in Western areas - such as Korea or Japan, where the average dwelling will be within range of between 15 and 20 different access points.
The hidden killers
Aside from interference, there are other “hidden” Wi-Fi speed killers – your choice of router security protocol, for instance. “WEP has a greater overhead and can, in some cases, cause a performance loss of up to 30%,” a spokesman for router manufacturer Belkin told us, providing yet another reason to dump the outdated and now insecure mode of traffic encryption. “WPA/WPA2 is more efficient and should, on any modern router, only reduce performance by a maximum of 5-10%. In most cases, however, it won’t be measurable.”
Running a completely unsecured router is the easiest way to maximise traffic throughput, but also the easiest way to hand access to your data to eavesdroppers and give your neighbours carte blanche to download anything they like on your account. As Belkin points out, the small loss of performance using WPA/WPA2 “should be seen as an acceptable exchange” for security.
The positioning of your router can also have a tremendous impact on performance. “Problems start to occur when you get the router in the wrong position, such as on the floor or behind a cabinet,” said Roger Tao. “People are hiding it because they don’t want to see it.”
Click for the next page - We reveal common wireless killers around the house...