NIC

Network Interface Card. The card between your computer and the network ;)

/sbin/ifconfig -a

should show you all currently installed and detected interface cards in your UBO. If not, try to find it by scrolling through dmesg

dmesg | less -XF

Linux
mii-tool will provide more information about your NIC:

eth0: negotiated 100baseTx-FD flow-control, link ok
 * 1) mii-tool

in this above case it shows I'm using 100baseT full duplex and the link is OK.