usb0 interface not see

When I booted the Beaglebone Black from eMMC ,I got 3 interfaces (usb0,lo,eth0) when I did the “ifconfig” command.Then
I tried an SD card with the latest Angstrom image( Angstrom Distribution (BeagleBone, BeagleBone Black - 4GB SD) 2013-06-20 ) downloaded from But, I got only 2 interfaces.(l0,eth0). usb0 is not seen.

Can anyone please help?

Thanks and Regards,