none of the special features of bonded ports described in this section
apply.
-There are many forms of bonding, but ovs-vswitchd currently implements
-only a single kind, called "source load balancing" or SLB bonding.
-SLB bonding divides traffic among the slaves based on the Ethernet
-source address. This is useful only if the traffic over the bond has
-multiple Ethernet source addresses, for example if network traffic
-from multiple VMs are multiplexed over the bond.
+There are many forms of bonding of which ovs-vswitchd implements only
+a few. The most complex bond ovs-vswitchd implements is called
+"source load balancing" or SLB bonding. SLB bonding divides traffic
+among the slaves based on the Ethernet source address. This is useful
+only if the traffic over the bond has multiple Ethernet source
+addresses, for example if network traffic from multiple VMs are
+multiplexed over the bond.
Enabling and Disabling Slaves
-----------------------------
When a slave becomes disabled, the vswitch immediately chooses a new
output port for traffic that was destined for that slave (see
-bond_enable_slave()). It also sends a "gratuitous learning packet" on
-the bond port (on the newly chosen slave) for each MAC address that
-the vswitch has learned on a port other than the bond (see
-bond_send_learning_packets()), to teach the physical switch that the
-new slave should be used in place of the one that is now disabled.
-(This behavior probably makes sense only for a vswitch that has only
-one port (the bond) connected to a physical switch; vswitchd should
-probably provide a way to disable or configure it in other scenarios.)
+bond_enable_slave()). It also sends a "gratuitous learning packet",
+specifically a RARP, on the bond port (on the newly chosen slave) for
+each MAC address that the vswitch has learned on a port other than the
+bond (see bond_send_learning_packets()), to teach the physical switch
+that the new slave should be used in place of the one that is now
+disabled. (This behavior probably makes sense only for a vswitch that
+has only one port (the bond) connected to a physical switch; vswitchd
+should probably provide a way to disable or configure it in other
+scenarios.)
Bond Packet Input
-----------------
otherwise very simple in that, after LACP negotiation is complete,
there is no need for special handling of received packets.
+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.
+
SLB Bonding
-----------