Cisco Systems N5KC5596TFA manual LACP Marker Responders

Configuring Port Channels

Understanding LACP

Table 6: Channel Modes for Individual Links in a Port channel

Channel Mode	Description
passive	LACP mode that places a port into a passive
	negotiating state, in which the port responds to LACP
	packets that it receives but does not initiate LACP
	negotiation.
active	LACP mode that places a port into an active
	negotiating state, in which the port initiates
	negotiations with other ports by sending LACP
	packets.
on	All static port channels, that is, that are not running
	LACP, remain in this mode. If you attempt to change
	the channel mode to active or passive before enabling
	LACP, the device returns an error message.
	You enable LACP on each channel by configuring
	the interface in that channel for the channel mode as
	either active or passive. When an LACP attempts to
	negotiate with an interface in the on state, it does not
	receive any LACP packets and becomes an individual
	link with that interface; it does not join the LACP
	channel group.

Both the passive and active modes allow LACP to negotiate between ports to determine if they can form a port channel, based on criteria such as the port speed and the trunking state. The passive mode is useful when you do not know whether the remote system, or partner, supports LACP.

Ports can form an LACP port channel when they are in different LACP modes as long as the modes are compatible as in the following examples:

•A port in active mode can form a port channel successfully with another port that is in active mode.

•A port in active mode can form a port channel with another port in passive mode.

•A port in passive mode cannot form a port channel with another port that is also in passive mode because neither port will initiate negotiation.

•A port in on mode is not running LACP.

LACP Marker Responders

Using port channels, data traffic may be dynamically redistributed due to either a link failure or load balancing. LACP uses the Marker Protocol to ensure that frames are not duplicated or reordered because of this redistribution. Cisco NX-OS supports only Marker Responders.

Cisco Nexus 5000 Series NX-OS Interfaces Configuration Guide, Release 5.2(1)N1(1)

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