Lacp Marker Responders; Cisco Nexus 3000 Series Nx-Os Layer 2 Switching Configuration Guide, Release 5.0(3)U1(1 - Cisco Nexus 3000 series Configuration Manual

Configuring EtherChannels
The following table describes the channel modes.
Table 5: Channel Modes for Individual Links in an EtherChannel
Channel Mode
passive
active
on
Both the passive and active modes allow LACP to negotiate between ports to determine if they can form an
EtherChannel, 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 EtherChannel 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 an EtherChannel successfully with another port that is in active mode.
• A port in active mode can form an EtherChannel with another port in passive mode.
• A port in passive mode cannot form an EtherChannel 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 EtherChannels, 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 3000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U1(1)

Description
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.
LACP mode that places a port into an active
negotiating state, in which the port initiates
negotiations with other ports by sending LACP
packets.
All static EtherChannels, 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.
Understanding LACP
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