What does "If 0 " or "If 1 " tells me in lsusb -t -v ?

[anneranch]

I have edited / cut most of the output


qw@qw-desktop:~$ lsusb -t -v

|__ Port 3: Dev 5, If 0, Class=Wireless, Driver=btusb, 12M
ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
|__ Port 3: Dev 5, If 1, Class=Wireless, Driver=btusb, 12M
ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
|__ Port 4: Dev 16, If 0, Class=Hub, Driver=hub/7p, 480M
ID 2001:f103 D-Link Corp. DUB-H7 7-port USB 2.0 hub
|__ Port 5: Dev 21, If 0, Class=Mass Storage, Driver=uas, 480M
ID 0bc2:2322 Seagate RSS LLC SRD0NF1 Expansion Portable (STEA)
|__ Port 3: Dev 19, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
ID 046d:c016 Logitech, Inc. Optical Wheel Mouse
|__ Port 1: Dev 17, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M
ID 045e:00f1 Microsoft Corp.
|__ Port 1: Dev 17, If 1, Class=Human Interface Device, Driver=usbhid, 1.5M
ID 045e:00f1 Microsoft Corp.