Hello Mr. Spencer, Thank you for your great questions.

Q. "B/G/N-Mixed—(Default) Connects all the wireless client devices at their respective data rates in this mixed mode." What does this mean exactly? Does it mean that I can have some clients using G at G speed; and some clients using N at the faster N speed? And both at the same time?

A. Look at it this way: The AP's can do at N rates 300Mbps that is raw data rate, but given the half duplex environment and management/control over head you end up getting about 150Mbps throughput to share between all clients on that ap/channel. When a b or g client shows up we have to lower the transmission rate on some messages so that they will understand them (Beacons/Probe Response) and before the N clients are allowed to send a message they have to send a RTS/CTS or CTS self at the B/G rates so that they know the N client will be using the channel for whatever period of time the G/B clients work at normal speed, the throughput on the N clients drops to about 100Mbps because of it. Basically the data rate stays the same, the actual throughput will drop.

Q. Should I set the Channel Bandwidth to 20Mhz or 40Mhz? The admin guide says that N will use 40Mhz and B/G will use 20Mhz. What is the difference in practice?

A. The 40mhz band is to increase the data throughput rate that the router runs. This is used in conjunction with the 802.11N band. Unless you also have a N-type card on your desktop/laptop then it is pretty much useless. When running B/G devices I would stay with 20Mhz.

Hope this helps, if any other questions please let me know.

Many thanks for that great info. I think the bottom line is that if you are in a mainly N environment, but with the odd chance of a few G users, then B/G/N is just fine. In practice, 100Mbps has got to be fine for most setups.

With respect to the 2nd question, is the bottom line that if I'm using B/G/N, and can/should turn 40Mhz on, and that I will get a better throughput?

Thanks.

Personally, I have never used this in a mixed environment, I mostly have G devices at home.(Only one N device). If you have more N devices, I say sure turn it on. the though-put on those N devices should be good.

Eric Moyers

I realize this is a very old thread, but I'm confused as I dig into this. If the B/G uses a completely different radio channel frequency method (DSSS) than N (OFDM), then how on earth does one send a RTS / CTS that the devices using a different mode would recognize and respect? To me, that seems like saying that a radio automatically knows if a signal received is FM or AM on the same frequency and automatically switches (actually, doing that would be *easier* than DSSS to OFDM).