Real-world tests of 802.11n technology: How does it rate?

Last week, I took a look at what various hardware providers are saying about the performance of their new 802.11n or 'Wireless N' product lines. The general message was that the next generation of wireless systems are faster and more powerful than ever before: up to five times faster along with up to twice the range. These high throughput devices are designed specifically with the needs of today's users in mind with high quality streaming media being consumed at an increasing rate.

Anybody who's used a wireless access-point or router will know that you never really get the types of range or coverage claimed on the box. Real world conditions tend to interfere and dramatically reduce the access point's coverage. Structural barriers like walls and doors will of course greatly reduce the range, while electronic interference coming from microwave ovens and mobile devices will cause throughput to suffer. I read a recent summary of the Farpoint Group's research on the causes and effects of interference; microwave ovens caused throughput to be reduced by up to 62%; Bluetooth headsets reduced throughput by 20%; and some wireless devices such as cordless phones reduced throughput by 100%. Now these examples are pretty extreme but they do highlight some of the many sources of interference in an average household or workplace.

So how will 802.11n devices really perform in the home? I've taken out my old Netgear DG834PN 'RangeMax' modem/router and replaced it with the DG834N from Netgear's latest 'RangeMax Next' line in hope of finding out whether or not 802.11n is worth all the fuss. While the DG834PN is capable of 108 Mbps if using the correct client adaptors, I have been using it in standard 802.11g mode (54 Mbps) as my wireless adaptors are 802.11g/n; not the Netgear 108 Mbps units.

While the external appearance of the two routers couldn't be more different (gone are the flashing blue lights), in terms of hardware, the two devices are exactly the same — a reset button, ADSL connector, power socket, and a four-port hub. All very straight forward. In terms of configuration, there is little to do. Make sure everything's plugged in to the right place, switch it on, browse to the admin page, and start the setup wizard. The router attempts to detect the connection type and automatically configure itself. In my case this worked brilliantly, my only input being the ISP-provided username and password. The actual software of the router is identical to that of the previous model which is nice as I don't have to learn anything new! Of course there is an additional option in the wireless configuration menu: 270Mbps! It's worth noting that if you're using the wireless access point at full speed then there are only two options for encryption: None or WPA-PSK [TKIP] + WPA2-PSK [AES]. If you have any older wireless clients that only support WEP encryption then it's going to be time to do some upgrading — this is really for the best as even home users should avoid using WEP; it's too easily broken.

That's the installation covered. Now for some simple tests. I must point out that these tests are not carried out with scientific precision; they are simple performance indicators in a real world environment to give me an idea of how the two technologies compare for day-to-day use.

The first test is of throughput. Grab a 1-GB file (in my case a .vob) and see how long it takes to transfer from a wireless machine to a computer connected to the wired LAN ports.

'Wireless G' transfer time: 9 minutes

'Wireless N' transfer time: 6 minutes

The second test was throughput again, but this time from one wireless client to another. The test is with the same 1GB file.

'Wireless G' transfer time: 14 minutes

'Wireless N' transfer time: 9 minutes

The third test was again of throughput, but this time rather than measuring the transfer times of a specific file, I wanted to see how streaming media performance varied. To do this I had one machine playing a 192-Kbps iTunes radio station and a second machine playing music from the shared iTunes library of the first machine. Both machines use wireless networking of 802.11g / 802.11n. The results of this test were interesting; I found that while using 802.11g both the first and second machines played music faultlessly, no jitter or re-buffering required. While using 802.11n, designed for HD streaming media with 'Steady-Stream' technology — I actually had some problems. Even with the buffering set to maximum, the Internet radio station frequently cut off and decided to re-buffer. I would have put this down to random Internet congestion except streaming music from the shared iTunes library also suffered, constantly stopping to re-buffer.

My final test was range. Very simply, I took my notebook and moved down my garden until the signal became unusable. The DG834PN 'RangeMax' router had actually significantly increased my range over the unit I had previously installed (a standard Belkin 802.11g modem/access point); with the DG834PN I would get about 50 meters down the garden while maintaining a useable connection. I was pretty happy with this considering the router is actually in a cupboard under the stairs at the centre of the house. The 'RangeMax Next' again gave a considerable improvement. I found with the DG834N that I gained another 30-40 meters, allowing me to sit right at the bottom of the garden. I'm sure this will be appreciated in the summer, allowing me to disappear to a quiet spot!

Overall, I have to say that I'm happy with the performance increases. The throughput has increased by around 30% which can only be a good thing. It means copying large files over the wireless network is a little less painful than before! Increased range was not particularly important to me as the previous 'RangeMax' unit performed exceptionally well; however, the added coverage is a bonus, and I certainly can't complain about it. The only disappointment comes with the loss of quality and consistency while using streaming media services. It seems particularly strange seeing as Netgear are pushing their 'Steady-Stream' technology: "…a technology called 'Steady-Stream', which ensures your wireless network offers a steady constant connection, with sufficient bandwidth available to stream, download, browse the Internet, and transfer files all at the same time. With RangeMax™ NEXT Wireless N technology you should not experience any more frustrating interruptions or freezes, just a constant connection that enables you and your household to use the Internet and wireless network as you choose, whenever you choose." Hopefully, the next firmware update will resolve this issue…

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