05 November 2008

Wireless Home Network


At the last post I talked briefly about the wireless site survey in networking projects.

Now I want to share my view in things that I personally consider in building wireless home network.
The following points are just my considerations, most home or SOHO users just plug their wireless access points, configure them and they just work fine.

Which Standard to Use

Currently there are four common standards for wireless networking, the 802.11a, 802.11b, 802.11g, and the latest one is 802.11n. These standards use unlicensed frequencies meaning they're all free for all to use.

You can use the frequencies for your wireless networks and you can't complain if your neighbors used up all of the frequencies available and interfere with your wireless signal.
Later on this when I talk about the wireless channels in a moment.

802.11a uses the 5GHz operational frequency and has a data rate transfer of 54Mbps. This standard is not too popular anymore because it has a higher frequency meaning it has higher data rates but with shorter range.
The higher the frequency also makes it more easily absorbed by solid objects around it.

802.11b and 802.11g use 2.4GHz operational frequency. Most wireless access points support both the b and g standards since they both use the same frequency they're both interoperable.
The difference is that the 802.11b has data rate transfer of 11Mbps while the 802.11g has 54Mbps.

The latest one is 802.11n, it uses 5GHz and/or 2.4GHz frequencies and in terms of data rate and wireless range, it has biggest data rate the widest range, some vendors claim their 802.11n access points can have data rates up to 114Mbps.

I don't know the truth about that since I don't have any 802.11n devices yet.
For me I just love the sleek looking design of 802.11n wireless router from Linksys.
Cool, gotta have that someday.

Wireless Access Points Locations

Place the access points in locations that you think can reach all the clients in the network. Consider the interferences from microwave oven or cordless phones.
Also keep in mind about objects that can block, absorb or reflect the signals from the access points such as thick wall or metal surfaces.

The further you get from the access points and the more objects standing between you and the access point, the lower data rate you'd get.

Channels to Use

If one wireless access point is enough to cover your clients, check on the wireless channels that are used by access points installed near your network.
If your access point uses the same channel as your neighbor's, they will interfere the wireless signals.
If you're using more than one access points, set them to use different channels.

In 802.11b and g standards, the common channels or the clean channels that you can use are channel 1, 6, and 11. Use one for each of your access point, do not use the same channel if the signals.
What I mean by clean channels is that these channels are not overlapping each other.
The following is the graphical representation of 802.11b and g wireless channels:

The 802.11a offers more clean channels for you to choose. You can see the wireless channels that you can use for 802.11a:


More on subjects on channels you can find directly at the source at the FCC site.

SSID

Service Set Identifier or SSID is like an ID for your wireless network. I'm sure you already know this, to join wireless network you need to know the SSID or you can scan for the SSID and join it.

You can use many available wireless network sniffers to scan the SSID and the wireless channels used by the wireless networks. Some of them you can find at the list here.
Once again not every sniffer works with your wireless network card, check on it before downloading.

You can use any SSID for your wireless network, your name, company name, etc. The reason I brought this up because if you're using the upper end wireless access points like from Cisco, you can have multiple SSID broadcasted from a single wireless access point.

Maybe you need a free for all SSID for your guests, another SSID for your home users or employees, and another one just for you as the admin.

In Cisco, you can tie these SSIDs to VLANs, this can give you flexibility in deciding different security for each SSID, different access list for them, etc.

Wireless Security


Now this is the most important part of all, the wireless security or the encryption method you want to associate with your SSID.
There are some types of wireless network authentication for security from the open authentication that you can apply for guests on your WLAN to the WPA version 2.
There are also WEP that is not so secure nowadays since people can tap on your signals and decrypt them.
Best to say that WPA or WPA2 are more secure to use in your WLAN, you can also use 802.1x security.

Remember that not all hardware or wireless NIC support all authentication, most of them support the WPA authentication so it's more common to use nowadays.

I got to admit I'm too lazy to give all explanation of them here plus this post takes longer than I expected.
Smarter and more diligent people have describe about this, one of them you can find at wikipedia.

I don't want to make you bore and start on the configuration of Cisco wireless network on the next posts.