Skip to main content
Super User

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

6
  • 802.11n is usually over 70% efficient. That is, your TCP/IPv4 throughput in a tool like iperf will be over 70% of your average PHY rate, and if you can hold the 300Mbps PHY rate (as is typical in perfect conditions) you should see well over 200Mbps. Of course a wireless-to-wireless transfer cuts that in half, so maybe that was your 90Mbps case?
    – Spiff
    Commented Mar 12, 2017 at 4:06
  • @Twisty Channel 1 at 40 MHz bonds 20MHz channels 1 and 5. Channel 11 at 40 MHz bonds 20MHz channels 11 and 7. So it has as much overlap as 20MHz channels on 5 and 7: 10MHz of overlap. So a quarter of your two 40MHz channels would be overlapping.
    – Spiff
    Commented Mar 12, 2017 at 4:12
  • @D'oh...of course. Channels 5 (and 7) would be the extension channels. I was trying to make it out that one would use a 40 MHz wide channel centered on channel 1 and 11, which is not correct. Need sleep...
    – I say Reinstate Monica
    Commented Mar 12, 2017 at 4:21
  • @Spiff - you seem to have wandered right past the 50% loss in actual speed from it being only half-duplex.
    – Ecnerwal
    Commented Mar 12, 2017 at 15:28
  • @Ecnerwal No, the half duplex is why it's only 70+% efficient instead of 94% efficient like full duplex Ethernet. Network flows are not symmetric. Tiny 802.11 acks and TCP acks take a very small percentage of the airtime compared to the 1500 byte data frames of a download.
    – Spiff
    Commented Mar 12, 2017 at 17:01