What is difference in throughput speed when using a usb adapter on a usb
1.1 usb system vs 2.0 on the same system for the same wifi link? IOW, what is the difference between the speed obtainable under each?- posted
18 years ago
USB 1.1;2.0;wifi speeds
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- posted
18 years ago
HymieGoogle hath wroth:
USB 1.1 is limited to 12Mbit/sec thruput. USB 2.0 high rate limits out at 480Mbits/sec and will handle any wireless USB speed known.
What gets weird is what happens when you plug a USB 2.0 802.11g wireless device into a USB 1.1 port. There are three possible algorithms.
- Take whatever wireless speed is possible and use TCP/IP flow control to throttle the connection. You can get a 54Mbit/sec wireless connection, but with a USB 1.1 port, the thruput will max out at around 9 to 11 Mbits/sec (there's some overhead).
- Slow the wireless connection down to where TCP/IP flow control is not needed. You'll get about a 12 or 18Mbit/sec OFDM (802.11g) connection, with a maximum thruput of 9 to 11 Mbits/sec.
- Turn off 802.11g completely and revert to 802.11b only. The USB device will switch to a maximum speed of 11Mbits/sec with a thruput of about 5Mbit/sec.