Wi-fi Router Neighbor-Friendly Mode?

Solution 1:

In radio terms, this option is allowing you to select between a 20MHz and 40MHz channel width. A 40MHz wide channel allows just a little more than twice the throughput (network bandwidth) of a 20MHz channel (because you get the equivalent of two 20MHz channels plus the "gutter" between them for one signal), but it takes up two channel slots.

In the narrow 2.4GHz band (originally used for b/g with 22MHz overlapping channels), only a single 40MHz channel will fit (note that 802.11n does not allow channels to overlap). This means that all 802.11n routers set to 2.4GHz (most of them) and to 40MHz channel width (fortunately not most of them) will be sharing the exact same radio space, and thus will slow eachother down. This can have an extreme impact in environments like apartment buildings and college dorms, where 802.11n set to 40MHz in the 2.4GHz band may perform worse (in terms of network throughput) than 802.11g.

This is the key reason that the WiFi alliance and, more slowly, manufacturers promote the 5GHz band for 802.11an. It is significantly wider than the 2.4GHz band, and allows for a comfortable number of non-overlapping 40MHz channels. The 5GHz band is also used solely by 802.11an (and limited other network applications), unlike the "general home RF" 2.4GHz band that WiFi shares with older DECT, analogue audio devices, etc (which are not WiFi aware and can significantly impact performance of nearby WiFi networks).

Even in the 5GHz space, though, there are only 2, 4, or 6 (depending on which U-NII bands your devices use, which is something I'm not familiar with) 40MHz channels available, so sticking to 20MHz is decidedly more neighbor-friendly in a crowded environment.

Solution 2:

For higher data transmission rates, your router radio broadcasts over a wider range of frequencies. This wider transmission band is more likely to interact negatively with other wireless networks in close channels.

Looking at the available wireless networks in your area, if you can view the channels those networks are broadcasting on, if there is a space of 5 or more empty channels together, telling your own router to broadcast in the middle-most channel, you're highly unlikely to cause problems with your neighbors networks.

If there is not so much room, it may be nice to use the "friendly" mode.

At the same time, who'll think that a neighbors wireless broadcast too aggressively is the cause of their new network troubles...

Personally, I'd compare real-life network speed between the two options and, if there isn't much difference in real life, I'd stick to the lower of the two.

UPDATE:

The 5 channel spread is an estimate based on realistic environments. If you're in the boonies there's no interference concerns at all. If you're in an average neighborhood, it's highly unlikely you'll find enough space in the available spectrum to avoid interference of some kind with your neighbors