Interoperability scenarios

Consider the following interoperability scenarios when configuring your EtherChannel or IEEE 802.3ad Link Aggregation.

Additional explanation of each scenario is given after the table.

Table 1. Different AIX and switch configuration combinations and the results each combination will produce.
EtherChannel mode Switch configuration Result
8023ad IEEE 802.3ad LACP OK - AIX® initiates LACPDUs, which triggers an IEEE 802.3ad Link Aggregation on the switch.
standard or round_robin EtherChannel OK - Results in traditional EtherChannel behavior.
8023ad EtherChannel Undesirable - AIX and Switch cannot aggregate. AIX initates LACPDUs, but the switch ignores them and do not send LACPDUs to AIX. Due to missing LACPDU, AIX does not distribute packets on the link/port. The result is loss of network connectivity.
standard or round_robin IEEE 802.3ad LACP Undesirable - Switch cannot aggregate. The result might be from poor performance as the switch moves the MAC address between switch ports

A brief description of each configuration combination follows:

  • 8023ad with EtherChannel :

    In this case, AIX will send LACPDUs, but they will go unanswered because the switch is operating as an EtherChannel. As a result, due to missing LACPDU, AIX will not use the link/port for packets distribution. This will cause loss of network connectivity.

    Note: In this case, the entstat -d command will always report the aggregation is in the Negotiating state. Also, in the entstat output, the section IEEE 802.3ad Port Statistics will show the Distributing is disabled for the Actor.
  • standard or round_robin with EtherChannel:

    This is the most common EtherChannel configuration.

  • standard or round_robin with IEEE 802.3ad LACP:

    This setup is invalid. If the switch is using LACP to create an aggregation, the aggregation will never happen because AIX will never reply to LACPDUs. For this to work correctly, 8023ad should be the mode set on AIX.