When we moved into our new apartment, we renewed all wires which included proper cat7 in all rooms. So lets take advantage of it... :)
My primary machine is a laptop that I carry around in the house a lot. This breaks open network connections, due to the IP change when NetworkManager switches from the wired interface to the wireless. To not interrupt existing network connections though, it's vital that the machine's IP stays the same regardless of whether it is hooked up with the wired or wireless. This is where network bonding comes into play. It binds both physical devices wlan and eth into a logical one with a single IP address assigned (by remote DHCP). The kernel then takes care of activating the proper device depending on the wired link state (cable connected).
apt-get install ifenslave me@foo:/etc/NetworkManager $ cat NetworkManager.conf [main] plugins=ifupdown,keyfile dns=dnsmasq [ifupdown] managed=false [keyfile] unmanaged-devices=mac:00:23:ab:cd:ef:14
"unmanaged-devices" tells NetworkManager to leave the bonding device alone and not interfere with it. It refers to the hw address (mac) of the wifi interface.
me@foo:/etc/network $ cat interfaces # Bonding for eth0 and wlan0 at home auto lo iface lo inet loopback # Do not receive dhcp on eth0 auto eth0 iface eth0 inet manual bond-master bond0 bond-primary eth0 # Manually connect wireless to AP #auto wlan0 iface wlan0 inet manual wpa-ssid "YOUR_SSID_HERE" wpa-psk YOUR_WPAKEY_HERE bond-master bond0 # Request dhcp ip for bonded interface iface bond0 inet dhcp bond-mode active-backup bond-miimon 100 bond-slaves none
Due to issues, wlan0 is brought up via 'ifup wlan0' in /etc/rc.local. Happy bonding (state can be observed via (cat /proc/net/bonding/bond0)
me@foo:/ $ cat /proc/net/bonding/bond0 Ethernet Channel Bonding Driver: v3.7.1 (April 27, 2011) Bonding Mode: fault-tolerance (active-backup) Primary Slave: eth0 (primary_reselect always) Currently Active Slave: eth0 MII Status: up MII Polling Interval (ms): 100 Up Delay (ms): 0 Down Delay (ms): 0 Slave Interface: eth0 MII Status: up Speed: 1000 Mbps Duplex: full Link Failure Count: 0 Permanent HW addr: 00:23:ab:cd:ef:13 Slave queue ID: 0 Slave Interface: wlan0 MII Status: up Speed: Unknown Duplex: Unknown Link Failure Count: 0 Permanent HW addr: 00:23:ab:cd:ef:14 Slave queue ID: 0
If one happens to install dropbear on Ubuntu 12.10 with an encrypted disk, network is set to come up as part of initramfs (to remotely unlock the disks). This causes ethX to get an IP address long before bonding has a chance to enslave the device. Removing dropbear and manually running "update-initramfs -u" fixed this issue for me.