Bridging a bonded network interface on ubuntu to a cisco switch using LACP 802.3ad

There are a lot of out of date howto's for doing bridging on linux. I found a good one - it is really easy (this is works on Ubuntu intrepid):

apt-get install ifenslave

Then change your /etc/network/interfaces - this setup bonds the two interfaces together so both are used to maximise throughput:

auto bond0
iface bond0 inet dhcp
  slaves all
  bond-mode 4
  bond-miimon 100

It is also possible to bridge a bonded interface, with a interfaces file like this (you'll also need bridge-utils):

auto bond0
iface bond0 inet manual
    slaves eth1 eth0
    bond-mode 4
    bond-miimon 100

auto br0
iface br0 inet static
 address 192.168.0.1
 netmask 255.255.255.0
 network 192.168.0.0
 broadcast 192.168.0.255
 gateway 192.168.0.254
        bridge_ports bond0
        bridge_fd 9
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off
 dns-nameservers 192.168.0.1
 dns-search my.lan

You switch needs to support 802.3ad, which apparently most modern ones do. I have it working with cisco following their howto, which boils down to:

Router> enable 
Router# configure terminal
Router(config)# interface port-channel 1
Router(config-if)# interface g1/0/24
Router(config-if)# channel-group 1 mode active 
Router(config-if)# exit
Router(config)# interface g1/0/23
Router(config-if)# channel-group 1 mode active 
Router(config-if)# end
Router# copy run start

This should give you lines like this (show run):

interface GigabitEthernet1/0/23
 channel-group 1 mode active
!
interface GigabitEthernet1/0/24
 channel-group 1 mode active
!