+Several of the physical switches that support LACP block all traffic
+for ports that are configured to use LACP, until LACP is negotiated with
+the host. When configuring a LACP bond on a OVS host (eg: XenServer),
+this means that there will be an interruption of the network connectivity
+between the time the ports on the physical switch and the bond on the OVS
+host are configured. The interruption may be relatively long, if different
+people are responsible for managing the switches and the OVS host.
+
+Such network connectivity failure can be avoided if LACP can be configured
+on the OVS host before configuring the physical switch, and having
+the OVS host fall back to a bond mode (active-backup) till the physical
+switch LACP configuration is complete. An option "lacp-fallback-ab" exists to
+provide such behavior on openvswitch.
+
+Active Backup Bonding
+---------------------
+
+Active Backup bonds send all traffic out one "active" slave until that
+slave becomes unavailable. Since they are significantly less
+complicated than SLB bonds, they are preferred when LACP is not an
+option. Additionally, they are the only bond mode which supports
+attaching each slave to a different upstream switch.
+