Link Aggregation Control Protocol Modes LACP modes specify whether a port can send LACP packets or only receive LACP packets. Table 2: EtherChannel LACP Modes Both the active and passive LACP modes enable ports to negotiate with partner ports to an EtherChannel based on criteria such as port speed, and for Layer 2 EtherChannels, based on trunk state and VLAN numbers. Ports can form an EtherChannel when they are in different LACP modes as long as the modes are compatible. For example: • A port in the active mode can form an EtherChannel with another port that is in the active or passive mode.
• A port in the passive mode cannot form an EtherChannel with another port that is also in the passive mode because neither port starts LACP negotiation. Link Aggregation Control Protocol Standalone Mode on Ethernet Channel When one end of an EtherChannel has more members than the other, the unmatched ports enter the standalone state. The standalone mode is also called the independent mode. In the standalone mode the port is not bundled in an EtherChannel. The port functions as a standalone data port and it can send and receive BPDUs and data traffic.
In a topology that is not protected from Layer 2 loops by the spanning tree protocol (STP), a port in the standalone state can cause significant network errors. You can enter the port-channel standalone-disable command in the interface configuration mode to put ports into the suspended state instead of the standalone state. The standalone mode is particularly relevant when a port (A) in a Layer 2 LACP EtherChannel is connected to an unresponsive port (B) on the peer. When LACP standalone is disabled on the EtherChannel, all traffic arriving on A is blocked (the default behavior on a switch). In some scenarios, you might want to allow management traffic on such ports.
You can do this by enabling LACP standalone (or independent) mode. To enable the standalone mode on a Layer 2 LACP Etherchannel, use the no port-channel standalone disable command in the interface configuration mode. To disable the Standalone mode and revert to the default use the port-channel standalone disable command in the interface configuration mode. LACP standalone mode is disabled by default. Note Starting with the Cisco IOS XE Dublin 17.10.1 release, you can configure the LACP standalone mode on a Layer 3 EtherChannel.
To configure the standalone mode use the no port-channel standalone disable Configuring EtherChannels Link Aggregation Control Protocol Modes Mode Description active Places a port into an active negotiating state in which the port starts negotiations with other ports by sending LACP packets. passive Places a port into a passive negotiating state in which the port responds to LACP packets that it receives, but does not start LACP packet negotiation. This setting minimizes the transmission of LACP packets. Configuring EtherChannels 6