Channels

Every Wi-Fi network communicates on a channel, a portion of the spectrum available. The 802.11 standard defined 14 channels, but different countries may limit exactly which channels may be used. In the United States, for example, a WAP may only use channels 1 through 11. These channels have some overlap, so it's not a good idea to have two nearby WAPs to use close channels like 6 and 7. Most WAPs use channel 1, 6, or 11 by default to keep the channels as far apart as possible. You can fine-tune a network by moving WAPs to other channels to avoid overlap with other, nearby WAPs. This is especially important in environments with many wireless networks sharing the same physical space.