Lacp Interaction With Other Features; Etherchannel On Mode; Load-Balancing And Forwarding Methods - Cisco Catalyst 2960-XR Configuration Manual

Configuring EtherChannels
• A port in the active mode can form an EtherChannel with another port that is in the active or passive
• A port in the passive mode cannot form an EtherChannel with another port that is also in the passive
Related Topics
Configuring Layer 2 EtherChannels, on page 123
EtherChannel Configuration Guidelines, on page 120
Default EtherChannel Configuration, on page 119
Layer 2 EtherChannel Configuration Guidelines, on page 122

LACP Interaction with Other Features

The DTP and the CDP send and receive packets over the physical ports in the EtherChannel. Trunk ports send
and receive LACP PDUs on the lowest numbered VLAN.
In Layer 2 EtherChannels, the first port in the channel that comes up provides its MAC address to the
EtherChannel. If this port is removed from the bundle, one of the remaining ports in the bundle provides its
MAC address to the EtherChannel. For Layer 3 EtherChannels, the MAC address is allocated by the active
switch as soon as the interface is created through the interface port-channel global configuration command.
LACP sends and receives LACP PDUs only from ports that are up and have LACP enabled for the active or
passive mode.

EtherChannel On Mode

EtherChannel on mode can be used to manually configure an EtherChannel. The on mode forces a port to
join an EtherChannel without negotiations. The on mode can be useful if the remote device does not support
PAgP or LACP. In the on mode, a usable EtherChannel exists only when the switches at both ends of the link
are configured in the on mode.
Ports that are configured in the on mode in the same channel group must have compatible port characteristics,
such as speed and duplex. Ports that are not compatible are suspended, even though they are configured in
the on mode.
You should use care when using the on mode. This is a manual configuration, and ports on both ends of
Caution
the EtherChannel must have the same configuration. If the group is misconfigured, packet loss or
spanning-tree loops can occur.

Load-Balancing and Forwarding Methods

EtherChannel balances the traffic load across the links in a channel by reducing part of the binary pattern
formed from the addresses in the frame to a numerical value that selects one of the links in the channel. You
can specify one of several different load-balancing modes, including load distribution based on MAC addresses,
IP addresses, source addresses, destination addresses, or both source and destination addresses. The selected
mode applies to all EtherChannels configured on the switch.
OL-29424-01
mode.
mode because neither port starts LACP negotiation.
Catalyst 2960-XR Switch Layer 2 Configuration Guide, Cisco IOS Release 15.0(2)EX1
EtherChannel On Mode
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