Port bonding is the aggregation of multiple physical network ports (servant interfaces) that form a new logical interface (master interface). The most common example of port bonding is putting two physical interfaces together to form an active/standby interface. If the active physical port loses carrier, the logical interface fails over to the standby without assistance from higher-level software.

For Avaya SBC Release 8.1.0 and later, only interfaces A1/A2 and B1/B2 can be paired to form a bonded interface. If one pair is bonded, the other pair must also be bonded. The resulting bonds are A1 for the A1/A2 pair and B1 for the B1/B2 pair. Thus, bonding for the A1/A2 and B1/B2 interfaces are either on or off. You cannot have bonding on one pair and no bonding on the other pair.

Consider the following conditions when configuring port bonding:

• After enabling or disabling port bonding, you must reboot the server. Do this reboot during a maintenance period or during low or no traffic periods.

• HA logic does not consider master/servant status when making failover decisions. Physical link failure might be good criteria to consider when making a failover decision, but HA logic is not aware of the link status when port bonding is enabled.

• Bonded interfaces are named A1 and B1. The servant interfaces are renamed by appending _phys to the original name, for example, A1_phys.

  The following diagram shows how the ports are renamed after port bonding is enabled:

  
  
  

  

  
  
  

• Port bonding configurations are not backed up. This means that if you are upgrading to a new release and port bonding was configured on the old system, you must reconfigure port bonding.

• Enabling and disabling port bonding must be done on each server in an SBC pair. If you fail to configure matching port bonding across server pairs, the interfaces will not operate properly.

• If interfaces A2 and B2 are already configured as active interfaces, those interfaces will not work when bonding is enabled. Existing configurations on A1 and B1 will continue to work, but existing configurations on A2 and B2 will cease to work because they are now servant interfaces for the new A1 and B1 bonds. Any configuration that uses A2 and B2 must be deleted before you enable bonding, and possibly reconfigured to A1 or B1, if required.

• The NIC port drivers using port bonding must support Media Independent Interface (MII). Ports that do not support MII cannot use port bonding. Port bonding is also not supported on servers that use the TILEncore-Gx36 network interface card.