ping

Netgear lies! 802.11n will (probably) not give you higher speed and better coverage

When my ADSL modem and Wi-Fi access-point died I decided I might as well buy the latest and greatest even though 802.11n was still a draft standard. So I bought a new 802.11n Wi-Fi access point/router/ADSL modem (Netgear DG834N) and I fitted 802.11n PCI cards (Netgear WN311B) into the various PC’s we have in the house.

802.11n was supposed to give me wider coverage and higher speed. “Supposed to” is the key in the previous sentence. I have absolutely no better coverage than with 802.11g and the real bandwidth is only very marginally better.

I decided to test using ttcp which is a program that only tests the actual network pipe, it is not a fileserver test. In all tests I ran one copy of ttcp on my Linux server and another copy on the workstations. I first ran ttcp on the PCs equipped with 802.11n PCI cards and then I ran, from the exact same location, the same test on my laptop which is equipped only with 802.11g. So when I say there is no real difference in the network performance it is not just a guess or a feeling, it is based on facts.

I just couldn’t understand why I didn’t get any of the supposed benefits of using pure 802.11n equipment, much higher speed and better coverage, so I did a bit of research (otherwise known as Googling), and this is what I learnt.

The 802.11n standard supports data transmission both in the 2.4 and in the 5 GHz frequency bands. The 2.4 GHz frequency band is the same one used by the 802.11b and 802.11g standards. Where I live I can detect 12 other 802.11g-based access-points. My Netgear DG834N device only supports data-transmission in the 2.4 GHz frequency band which it has to share with all the other access-points. My access-point supports something called “channel expansion mode” to achieve the theoretical 270Mbps, and it can’t do that as it has to avoid problems with the transmission from the other non-802.11n access-point. High bandwidth using the 2.4 GHz frequency band is only possible where there are very few or no other access-points using that frequency band. In other words, if you are in the same situation as I am, lots of neighbours with 802.11b or 802.11g-based access-points, either forget about buying 802.11n-based equipment, or ensure the 802.11n equipment you buy supports the 5 GHz frequency band.

I must admit to feeling cheated. On their website Netgear show how 802.11g gives you speed 1x and coverage 1x whereas 802.11n supposedly gives me 15x speed and 10x coverage. Nowhere did they tell me that would only be the case if the airwaves where practically free of data-transmissions from other 802.11g-based access-points. Since I bought the Netgear DG834N access-point, they have released a dual-band access-point. In other words, it supports both the 2.4 and the 5 GHz frequency bands. And guess what, they do actually tell you on the page for that device that “Dual band wireless networks deliver better connections with less interference”. Come clean Netgear (and other Wi-Fi vendors), tell it as it is, 802.11n-based access-points with 802.11n clients that only support the 2.4 GHz frequency band are probably not going to be any faster than are a 802.11g-based access-point.

Amongst my sources:

• 802.11n – The consequences of abandoning the 5 GHz frontier
• The truth about 802.11n, 2.4Ghz and 5.8Ghz

Tags: 2.4 GHz, 5 GHz, 802.11g, 802.11n, lies, Netgear