Link Aggregation Control Protocol (LACP) in AOS

Version 7

     

    Link Aggregation

     

    ADTRAN AOS supports Link Aggregation, which is defined in IEEE 802.3ad, and allows switches to aggregate Ethernet ports between ADTRAN switches or other switch manufacturers that conform to the 802.3ad specification. Link Aggregation allows you to bundle multiple Ethernet ports to form a single logical channel. An ADTRAN switch can support up to 6 channel groups; each of which can contain up to 8 ports per. This is beneficial in two ways: increased link capacity and providing for redundancy.

     

    When configuring Link Aggregation, all ports within the group must be configured with the same speed and duplex (Link Aggregation only works on FULL duplex). A port cannot belong to more than one channel  group at the same time. Load balancing is supported across multiple channel groups.

     

    Note that AOS does not support dynamic LACP: Active Mode (generating negotiation request) nor Passive Mode (responding to negotiation request), meaning there is not a control protocol running at all. AOS only supports static Link Aggregation by unconditionally setting the port channel to “on” mode as seen below:

     

    NV1238(config)#interface port-channel 1

    Creating Port Channel interface 1.

     

    NV1238(config-p-chan1)#no shut

    2012.03.06 09:41:03 INTERFACE_STATUS.port-channel 1 changed state to administratively up

     

    NV1238(config-p-chan1)#interface switchport 0/21

     

    NV1238(config-swx 0/21)#channel-group 1 mode on

     

     

    When creating a Port Channel to a multi-port NIC, in a server for example, the NIC must have one Ethernet interface per aggregated switch port and support the IEEE 802.3ad standard for link aggregation. Be sure to check with your NIC manufacturer to ensure it supports 802.3ad, and that it will support the bandwidth of the logical link.

     

    A Port Channel may not be divided between switches; all ports of a Port Channel must physically reside on the same switch (unless in ActivChassis mode). AOS does not support Control Protocol (PAgP). This is a Cisco-proprietary protocol and only runs on Cisco switches.

     

    The configuration example below shows the required commands for doing LACP between an ADTRAN AOS switch and a Cisco switch.


    ADTRAN AOS switch

    !

    interface port-channel 1

      no shutdown

    !

    interface switchport 0/1

      no shutdown

      channel-group 1 mode on

    !

    interface switchport 0/2

      no shutdown

      channel-group 1 mode on

    !

    NOTE: Older AOS swtiches will have interfaces labeled "ethernet" instead of "switchport" - interface ethernet 0/1 vs switchport 0/1

     

    Cisco switch

     

    interface Port-channel 1

    !

    interface FastEthernet0/1

      channel-group 1 mode active

      channel-protocol lacp

    !

    interface FastEthernet0/2

      channel-group 1 mode active

      channel-protocol lacp

     

    NOTE: Depending on the Cisco IOS version, an alternate interface configuration may be as follows:

     

    interface FastEthernet0/1

      channel-protocol lacp

      channel-group 1 mode on