Recipe 3.9. Resolving USB Bandwidth Problems


Problem

You receive an error message: USB Controller Bandwidth Exceeded.

Solution

  1. Stop your audio or video device.

  2. Disconnect all other devices from the USB port you are using for your audio or video streaming device, or reconnect only the audio or the video device to another port or hub on another port.

  3. Restart your audio or video device.

  4. Do not connect new devices to the same port or hub as the streaming device.

Discussion

USB host ports are limited to a total maximum bandwidth high-speed USB 1.1 devices are capable of moving data at a maximum rate of 12MBps, while low-speed hosts provide 1.5MBps data rates. USB 2.0 devices can theoretically move data at 480 MBps. When a streaming device begins to stream, it reserves bandwidth on the port the device is connected to, limiting the remaining bandwidth available for other devices. A new device may demand additional bandwidth that the port cannot provide. By using a separate USB host port for streaming devices and another host port for additional devices, you can avoid the bandwidth limitations. Note that USB hubs do not constitute host ports but are merely expansions of a main USB host. Bandwidth reservation and limiting bandwidth available to other devices is considered "by design" according to USB specifications and does not indicate a problem with your hardware.

See Also

The true Univeral Serial Bus (USB) specification and FAQs about USB are available at http://www.usb.org. You will find additional information at http://www.intel.com/technology/usb/ and http://computer.howstuffworks.com/usb.htm.



Windows XP Cookbook
Windows XP Cookbook (Cookbooks)
ISBN: 0596007256
EAN: 2147483647
Year: 2006
Pages: 408

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