Comment 1 for bug 1461576

The ['openstack']['network']['openvswitch']['bridge_mapping_interface'] is defined to be:

   # Create OVS data network bridge for the physical network and configure it
   # with the specified port. If nil or empty string is specified, the data
   # network bridge will not be created.
   # Format: <data network bridge name>:<external interface>
   #
   # Example: bridge_mapping_interface = br-eth1:eth1
   default['openstack']['network']['openvswitch']['bridge_mapping_interface'] = nil

Perhaps you are thinking about the L3 properties which were implemented as two separate properties.

   # Name of bridge used for external network traffic. This should be set to
   # empty value for the linux bridge
   default['openstack']['network']['l3']['external_network_bridge'] = 'br-ex'

   # Interface to use for external bridge.
   default['openstack']['network']['l3']['external_network_bridge_interface'] = 'eth1'

The ['openvswitch']['bridge_mapping_interface'] was defined similar to how the ['openvswitch']['bridge_mappings'] property is defined.

   # Comma-separated list of <physical_network>:<bridge> tuples
   # mapping physical network names to the agent's node-specific OVS
   # bridge names to be used for flat and VLAN networks. The length of
   # bridge names should be no more than 11. Each bridge must
   # exist, and should have a physical network interface configured as a
   # port. All physical networks listed in network_vlan_ranges on the
   # server should have mappings to appropriate bridges on each agent.
   #
   # Example: bridge_mappings = physnet1:br-eth1
   default['openstack']['network']['openvswitch']['bridge_mappings'] = nil