Configuring Layer 2 Etherchannels - Cisco 3845 - Security Bundle Router Software Manual

Configuring EtherChannels
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Configuring Layer 2 EtherChannels

You configure Layer 2 EtherChannels by assigning ports to a channel group with the channel-group
interface configuration command. This command automatically creates the port-channel logical
interface.
Although you cannot assign a port configured with an EFP service instance to an EtherChannel, you can
Note
configure service instances on EtherChannel port channels.
Beginning in privileged EXEC mode, follow these steps to assign a Layer 2 Ethernet port to a Layer 2
EtherChannel. This procedure is required.
Command
Step 1 configure terminal
Step 2 interface interface-id
Step 3 switchport mode {access | trunk}
switchport access vlan vlan-id
Cisco ME 3800X and 3600X Switch Software Configuration Guide
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For Layer 2 EtherChannels:
– Assign all ports in the EtherChannel to the same VLAN, or configure them as trunks. Ports with
different native VLANs cannot form an EtherChannel.
– You cannot assign a port configured with a service instance to an EtherChannel.
– If you configure an EtherChannel from trunk ports, verify that the trunking mode is the same on
all the trunks. Inconsistent trunk modes on EtherChannel ports can have unexpected results.
An EtherChannel supports the same allowed range of VLANs on all the ports in a trunking
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Layer 2 EtherChannel. If the allowed range of VLANs is not the same, the ports do not form an
EtherChannel even when PAgP is set to the auto or desirable mode.
– Ports with different spanning-tree path costs can form an EtherChannel if they are otherwise
compatibly configured. Setting different spanning-tree path costs does not, by itself, make ports
incompatible for the formation of an EtherChannel.
For Layer 3 EtherChannels, assign the Layer 3 address to the port-channel logical interface, not to
the physical ports in the channel.
For configuring Ethernet Virtual Connections (EVCs), you can add a service instance to an
EtherChannel port channel.
Purpose
Enter global configuration mode.
Specify a physical port, and enter interface configuration mode.
For a PAgP EtherChannel, you can configure up to eight ports of
the same type and speed for the same group.
For a LACP EtherChannel, you can configure up to 16 Ethernet
ports of the same type. Up to eight ports can be active, and up to
eight ports can be in standby mode.
An EtherChannel port cannot be a port configured with a
Note
service instance.
Assign all ports as static-access ports in the same VLAN, or
configure them as trunks.
If you configure the port as a static-access port, assign it to only
one VLAN. The range is 1 to 4094.
Chapter 28 Configuring EtherChannels
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