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Configure Link Aggregation Control Protocol

Learn about Link Aggregation Control Protocol (LACP) on standalone devices. Also, learn how to configure LACP and LAG on standalone devices.

LACP on Standalone Devices

Link Aggregation Control Protocol (LACP) provides a standardized means for exchanging information between partner systems on a link. Within LACP, the local end of a child link is known as the actor and the remote end of the link is known as the partner.

Use Feature Explorer to confirm platform and release support.

LACP is enabled on an aex by setting the mode to either passive or active. To initiate the transmission of LACP data units (PDUs) and response link aggregation control PDUs, you must enable LACP at both the local and remote ends of the links.

  • Active mode—If either the actor or partner is active, the links exchange link aggregation control PDUs. The actor sends link aggregation control PDUs to its protocol partner that convey what the actor knows about its own state and that of the partner’s state.

  • Passive mode—If the actor and partner are both in passive mode, the links do not exchange link aggregation control PDUs. As a result, the aggregated Ethernet links do not come up. In passive transmission mode, links send out link aggregation control PDUs only when the links receive the PDUs from the remote end of the same link.

By default, the actor and partner transmit link aggregation control PDUs every second. You can configure different periodic rates on active and passive interfaces. When you configure the actor and partner interfaces at different rates, the transmitter (actor) honors the receiver’s (partner's) rate.

You configure the interval at which the interfaces on the remote side of the link transmit link aggregation control PDUs by configuring the periodic statement on the interfaces on the local side. It is the configuration on the local side that specifies the behavior of the remote side. That is, the remote side transmits link aggregation control PDUs at the specified interval. The interval can be fast (every second) or slow (every 30 seconds).

LACP for LAG

LACP provides additional functionality for LAGs. LACP is supported on L2 transparent mode in addition to existing support on L3 mode. For information about link aggregation for other SRX Series Firewalls, see the Ethernet Switching User Guide.

LACP provides a standardized means for exchanging information between partner (remote or far-end of the link) systems on a link. This exchange allows their link aggregation control instances to reach agreement on the identity of the LAG to which the link belongs, and then to move the link to that LAG. This exchange also enables the transmission and reception processes for the link to function in an orderly manner.

For example, when LACP is not enabled, a local LAG might attempt to transmit packets to a remote individual interface, which causes the communication to fail. An individual interface is a non-aggregatable interface. When LACP is enabled, a local LAG cannot transmit packets unless a LAG with LACP is also configured on the remote end of the link.

You configure an aggregated Ethernet virtual link by specifying the link number as a physical device. Then you associate a set of ports that have the same speed and are in full-duplex mode. The physical ports can be 100-megabit Ethernet, 1-Gigabit Ethernet, and 10-Gigabit Ethernet.

LACP is supported in standalone deployments, where aex are supported, and in chassis cluster deployments, where aex and redundant Ethernet interfaces are supported simultaneously.

Verify LACP on Standalone Devices

Verify LACP Statistics

Purpose

Display LACP statistics for aggregated Ethernet interfaces (aex).

Action

From operational mode, enter the show lacp statistics interfaces ae0 command.

The output shows LACP statistics for each physical interface associated with the aex, such as the following:

  • The LACP-received counter that increments for each normal hello

  • The numbers of LACP transmit packet errors logged

  • The number of unrecognized packet errors logged

  • The number of invalid packets received

Use the following command to clear the statistics and see only new changes:

Verify LACP Aggregated Ethernet Interfaces

Purpose

Display LACP status information for aggregated Ethernet interfaces.

Action

From operational mode, enter the show lacp interfaces ae0 command.

The output shows aggregated Ethernet interface information, including the following information:

  • The LACP state—Indicates whether the link in the bundle is an actor (local or near-end of the link) or a partner (remote or far-end of the link).

  • The LACP mode—Indicates whether both ends of the aggregated Ethernet interface are enabled (active or passive)—at least one end of the bundle must be active.

  • The periodic link aggregation control PDU transmit rate.

  • The LACP protocol state—Indicates the link is up ifit is collecting and distributing packets.