Notes on ubuntu network card fixed and floating IP, this is my setting on Nvidia TX2.
Other versions of ubuntu Linux should also be available
Modify
/etc/network/interfaces

Floating IP setting method

iface eth0 inet dhcp

Fixed IP setting method

# The primary network interface
auto eth0
iface eth0 inet static
    address 192.168.0.108
    netmask 255.255.255.0
    network 192.168.0.0
    broadcast 192.168.0.255
    gateway 192.168.0.1
    dns-nameservers 168.95.1.1 8.8.8.8
    dns-domain ccc.tc
    dns-search ccc.tc

Restart the network

 /etc/init.d/networking restart