Cabled Ethernet vs. WLAN’s

We did some fairly major renovation of the previous house we lived in and (amongst other things) had the electrician pull ethernet cabling to all rooms. As I also had a small 4-port ISDN PBX, this meant that I could connect by cable a PC and a telephone in every single room of the house. Back then, I only ever used wi-fi if for example I wanted to sit in the garden and work with the laptop.

So wi-fi was an occasional access method and an excellent one at that. Now I have two PCs in different parts of the house that are permanently connected via wi-fi and I plan on connecting other devices as well. It has been a lot fiddlier than I thought it would be. After some initial problems with getting a good enough signal to both PCs, it is working alright. But wi-fi is no match for a good old cabled connection.

I’m currently renting the house we live in so I can’t go around drilling holes in the walls, but next time I buy a house again I will have ethernet cables installed in all the rooms. Maybe newer WLAN standards will get rid of the problems with WLANs but here are some of the major issues with using it as the primary data transfer method:

Bandwidth

All my wi-fi devices are configured for 802.11g, in other words, a theoretical bandwidth of 54 Mbit/sec, but in practice somewhere closer to half of that. The difference in speed is so obvious when doing anything other than ordinary web-browsing where the limiting factor is the internet connection. I’ve got my photo albums stored on the server and there is a noticeable time lag between viewing photos on one of the wirelessly connected PCs and a cable connected PC using fast Ethernet (100 Mbit/sec). I have in the last couple of years occasionally digitised old VHS videotapes. I shudder at the thought of transferring a video by wi-fi to the server.

Shared media

related to the Bandwidth issue. With wi-fi you are using a shared media, and if you are not careful about which wi-fi channels you are using, you may even be sharing the media with your neighbours. Last time I ran Netstumbler on the laptop I saw (including my own) 16 different WLANs. 10 of them use channel 11, 3 use channel 1, 2 use channel 6 and 1 uses channel 12. With 802.11b and 802.11g there is an overlap in the frequency range used by the 14 (Europe) different channels. That frequency overlap means that WLANs that unless channels are chosen carefully, transmissions on one WLAN can slow down the performance of the other WLANs. To ensure there is no frequency overlap, the “safe” channels are 1, 6 and 11. Most resources I have seen on the internet refer to channel 6 being the factory-default channel on most wi-fi devices. My own network scanning around the world shows channel 11 to be the default. So my Access Point is set to channel 1. The other networks in my neighbourhood also using channel 1 are not very powerful. For more information on the frequency overlap of wi-fi channels I would recommend these articles:

Wireless phones and wi-fi

One related aside to shared media; many articles and manuals mention that microwave ovens and wireless phones use the same frequency band used by 802.11b and 802.11g WLANs. I think all newish wireless phones in Europe use the DECT standard, at least mine do. I did a quick internet search and DECT doesn’t use the same frequency band as wi-fi, so this must be a US only problem.

Security

Security is still an issue. Many people don’t know what they are doing or don’t seem to be thinking it through properly. From where I live I can access 3 open WLANs. I discussed this with an acquaintance who also works in the IT industry. His comment was that his access point also was open as he didn’t have any network traffic worth securing. I then asked him what he would do if somebody used his connection to download paedophile content, it would potentially be traceable to his home. I don’t know about the UK (where I currently live) but according to an article I just read in a German IT magazine, You can (in Germany) be prosecuted if your WLAN is used for illegal activities and you have not done anything to secure it. So security is important. Anybody who as read anything on wi-fi security will know that the first security mechanism available for wi-fi, WEP, is useless. But I’ve got a media-player device that only supports WEP which means I either have to use WEP on all devices or not use that particular device wirelessly. Well, I may have a work-around for that, more on this in a later post. But my issue with WLAN security is that it is too complicated for many people or they don’t take it seriously. The various encryption methods (WEP, WPA with TKIP or AES, WPA2) don’t exactly make it easier. And some older (but not that old) devices in effect don’t support any security.

Thursday, January 18th, 2007 LAN, Wireless LAN

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