virtualbox.org

I am using VirtualBox on Windows XP (SP3). I installed Fedora Linux on the virtual machine.
There are two USB Wifi Adaptors connected to the computer.

When I try to attach both USB Wifi Adaptor by
"Devices -> USB Devices -> Ralink 802.11 n WLAN [0101]
Devices -> USB Devices -> Ralink 802.11 n WLAN [0101]",
it is found that only one adaptor can be attached, but not both.

The only workaround is to use 2 USB Wifi Adaptor with different standards, e.g.
"Devices -> USB Devices -> Ralink 802.11 n WLAN [0101]
Devices -> USB Devices -> Ralink 54M.USB ........ [0001]"

Is it possible to attach 2 identical USB Wifi Adaptors at the same time?

Why would you want to use the USB devices directly when you can give the guest network access by bridging one or both of the adapters?

There is an access point for which a pair of login name and password is required. An unique pair of login name and password can only be used for login for one Wifi Adaptor connected to that access point at one time.

On my PC, one of the WiFi Adaptor connects to that access point which require login. The other WiFi Adaptor act as another access point to which my other laptops or mobile phone can be connected.

This setup can simply be called "WiFi as WAN". Some routers offer this functionality.

There should be no reason in VirtualBox why you can't connect both, if the host and guest OS's allow it, and the dongle itself. Naturally the OS has to be able to distinguish between them, otherwise how is network addressing supposed to work? If the dongles can't be distinguished then that's something you'd need to take up with the manufacturer.

Why would you want to use the USB devices directly when you can give the guest network access by bridging one or both of the adapters?

Bridging on Wifi does not always work. It DOES make sense to pass the adatpers to the guest.

To detailed a bit more mpack's answer : if the devices are the same, they generally end up having the same IDs. Since Virtualbox use these IDs to know which device to attach, you can't attach both at the same time. This is a known limitation.

I'm facing same problem please help me if anybody resolve the issue.

farooq wrote:I'm facing same problem please help me if anybody resolve the issue.

Which issue do you mean? It has not been established above that any VirtualBox issue exists. If the problem is that the device's own driver can't distinguish betweeen two identical devices then you'd have to take that problem up with the manufacturer.

When you enabled the USB filters for your USB-WiFi adapters, what do the values filled in look like?