I have a Cisco USB ethernet device plugged in to my 12.04lts. It shows up in lsusb as ASIX Electronics Corp. AX88772 and dmesg notes it:

asix 5-1:1.0: eth1: register 'asix' at usb-000:06:00.0-1 ASIX AX88772 USB 2.0 Ethernet c0:c1:c0:94:f7:bd

(Updating...) I see it listed in /etc/udev/rules.d/70-persistent-net.rules as...

# USB device 0x0b95:0x7720 (usb)

SUBSYSTEM=="net"", ACTION=="add", DRIVERS=="?*", ATTR{address}=="c0:c1:c0:94:f7:bd", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL="eth*", NAME="eth1"

So USB has it, and part of the network system has it, but there is no eth1 in ifconfig and ifup eth1 says

Ignoring unknown interface eth1=eth1

How do I get it working?