aadhar
10-21-2009, 08:08 PM
I implement 802.11n in my network with already 802.11b/g existing would this downgrade the entire network to 802.11b speeds?
View Full Version : 802.11n
WHT
10-21-2009, 09:31 PM
11 Mbps B defeats the advantage of 54 Mbps G
11 Mbps B and/or 54 Mbps G defeats the advantage of AirMax M family of N radios.
Therefore, there is no sense in using G if mixed with B clients, and no sense to mix AirMax with non-AirMax units.
11 Mbps B and/or 54 Mbps G defeats the advantage of AirMax M family of N radios.
Therefore, there is no sense in using G if mixed with B clients, and no sense to mix AirMax with non-AirMax units.
mivpl
10-23-2009, 07:39 PM
11 Mbps B and/or 54 Mbps G defeats the advantage of AirMax M family of N radios.
yeow
10-24-2009, 07:12 AM
You won't get your desired 130Mbps (20MHz HT20 for 802.11n) or 300Mbps (40MHz HT40 for 802.11n) as long as one 802.11a or b or g device connects your 802.11n network.
doddel
11-05-2009, 01:41 AM
for those contemplating switching to 802.11n for the sake of bandwidth:
1. some modern chipsets offer this capability at a low price. However they may require the data processing and encryption/decryption to be done elsewhere, i.e. by the CPU on the motherboard. As one normally would apply e.g. wpa-psk this caps speeds quite substantially and eats into CPU capability. Some older chipsets in combination with just a 180 MHz CPU may do better than some modern with a 680 MHz CPU. Check this before buying the radio parts. The manufactures in my opinion have made some severe architectural errors there in order to reach price points.
2. maximum speed is ruled by he ability to demodulate the data reliably from the radio signal. Adding frequency spectrum to a communication channel, i.e. making it 'wider', only increases data transport if per unit of frequency band full use was made of the spectrum and frequency space was in shortage, and not signal strength.
In other words, if e.g. in g mode you run at the full 54 Mbps and there is enough headroom in signal strength it makes sense to make more space available through another 802.11 mode. So the antenna situation, interference situation, and quality of radio circuits is probably more important than the mode. You wiĺl be disappointed if already in the current situation speed was not limited by the mode but by other effects.
3. in a situation with more clients talking to an AP there are issues of
a) the 'hidden node' (one client sending because it cannot hear another sending but so impeding the AP from receiving properly) which requires the RTS/CTS system to be active and
b) the issue of a client having poor signal strength and having negotiated a low bit rate as a consequence of that. It then takes longer to send a certain amount of data and the other clients, despite having great signals, cannot send and receive during the time taken by the slow one. So pay attention to the weakest brothers and do something about that (better antenna, less obstacles)
1. some modern chipsets offer this capability at a low price. However they may require the data processing and encryption/decryption to be done elsewhere, i.e. by the CPU on the motherboard. As one normally would apply e.g. wpa-psk this caps speeds quite substantially and eats into CPU capability. Some older chipsets in combination with just a 180 MHz CPU may do better than some modern with a 680 MHz CPU. Check this before buying the radio parts. The manufactures in my opinion have made some severe architectural errors there in order to reach price points.
2. maximum speed is ruled by he ability to demodulate the data reliably from the radio signal. Adding frequency spectrum to a communication channel, i.e. making it 'wider', only increases data transport if per unit of frequency band full use was made of the spectrum and frequency space was in shortage, and not signal strength.
In other words, if e.g. in g mode you run at the full 54 Mbps and there is enough headroom in signal strength it makes sense to make more space available through another 802.11 mode. So the antenna situation, interference situation, and quality of radio circuits is probably more important than the mode. You wiĺl be disappointed if already in the current situation speed was not limited by the mode but by other effects.
3. in a situation with more clients talking to an AP there are issues of
a) the 'hidden node' (one client sending because it cannot hear another sending but so impeding the AP from receiving properly) which requires the RTS/CTS system to be active and
b) the issue of a client having poor signal strength and having negotiated a low bit rate as a consequence of that. It then takes longer to send a certain amount of data and the other clients, despite having great signals, cannot send and receive during the time taken by the slow one. So pay attention to the weakest brothers and do something about that (better antenna, less obstacles)
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