Broadband Advisor

Not convinced that superfast 802.11n Wi-Fi is for you? Allow us to persuade you.

1. Speed: 802.11n promises the fastest wireless networking yet. Figures are somewhat vague, with speeds of 270 to 300 megabits per second (Mbps) commonly quoted.

Most draft-n products typically offer 300Mbps with OFDM, a 2_2 (two receiving and two transmitting streams) configuration and a 40MHz channel width. Real-world throughput will be less - perhaps 75Mbps.

2. Range: You can expect a greatly improved broadcast range with 802.11n. It's tricky to predict the true range of Wi-Fi, but in free air you might get a range of 100ft with 54Mbps 802.11g; this will increase up to 300ft with 802.11n, in theory. In practice, expect a doubling of range indoors, good enough even for the largest of houses.

3. Security: Draft-n devices are the most secure wireless products available - they use Wi-Fi Protected Access 2 (WPA 2).

The original WPA didn't feature all the elements of the 802.11i security standard, but WPA 2 does. In addition to TKIP and the 'Michael' encryption algorithms, 802.11n introduces a new Advanced Encryption Standard (AES)-based algorithm, CCMP, which is considered fully secure.

4. Backward compatibility: 802.11n is backward-compatible with both 11Mbps 802.11b and 54MBps 802.11g wireless networks, meaning you can mix and match Wi-Fi standards on a single network.

This does come at a price, however: 802.11n devices will drop from using two channels to one when it detects older Wi-Fi devices present. This will halve bandwidth.

5. Mimo: Although multiple in, multiple out (Mimo) technology first appeared in late 802.11g devices, 802.11n makes heavy use of it.

Previously, multipath errors (where radio signals bounce off many surfaces and the reflections confusingly arrive at different times) were bad news for 11b and 54g Wi-Fi. 802.11n uses Mimo to extract more bandwidth from these reflections. This makes draft-n a far better bet for 'awkward' locations.

6. Improved sharing: Thanks to the extra bandwidth that 802.11n bestows, it's now possible to share a wireless connection without sacrificing signal strength. In other words, you can run more wirelessly connected PCs before you start to notice a fall-off in bandwidth.

7. Wi-Fi Multimedia support: 802.11n technology is the only wireless technology today with the bandwidth to support multiple high-definition TV streams at 20Mbps each.

This performance is sufficient for supporting a variety of multimedia, including VoIP, data, video and gaming in residential applications. Much of this is down to the fact that draft-n incorporates the 802.11e quality of service (QoS) standard, which guarantees priority for multimedia traffic.

8. Interoperability: Early drafts of 802.11n led to hardware that was notorious for not being interoperable with other vendors' draft-n kit. Although the 802.11n standard won't be ratified till later this year, the Wi-Fi Alliance is now certifying more recent draft 2 802.11n hardware.

This guarantees that mix-and-match draft-n hardware will work together, that they share the same security methods and are backward-compatible. A list of certified products can be found here.

9. Dual-Band 802.11N: Most draft-n kit uses the crowded 2.4GHz band, but the standard also permits 5GHz use. New dual-band hardware, such as the D-Link DIR-855, makes good use of this by confining media streaming to the 'quiet' 5GHz band while day-to-day filesharing and internet connection shares to the 2.4GHz band.

10. Gigabit networking: Plenty of routers come equipped with 100MBps fast ethernet wired ports, which will act as a bottleneck to the faster wireless traffic. Most PCs sold these days have gigabit network ports, so if you buy a draft-n router with gigabit support you'll also upgrade the performance of your wired network.