Bond with bridge

auto eth0
iface eth0 inet manual

auto eth1
iface eth1 inet manual

auto bond0
iface bond0 inet manual
slaves eth0 eth1
bond_miimon 100
bond_mode balance-tlb

auto vmbr0
iface vmbr0 inet static
address 192.168.xxx.xxx
netmask 255.255.255.xxx
gateway 192.168.xxx.xxx
bridge_ports bond0
bridge_fd 0
###bridge_vlan_aware yes

Bridge

auto eth1
iface eth1 inet manual
up ip link set eth1 up

auto br1
iface br1 inet manual
        bridge_ports eth1
        bridge_fd 0
        bridge_hello 2
        bridge_maxage 12
        bridge_stp off
        address 192.168.xxx.xxx
        netmask 255.255.255.xxx
        gateway 192.168.xxx.xxx

Tip: Do something when network goes on

post-up (  echo 1 > /sys/devices/virtual/net/$IFACE/bridge/multicast_querier )