Etherchannel Configuration Guidelines - Cisco ME 3400G-2CS - Ethernet Access Switch Software Configuration Manual

Configuring EtherChannels

EtherChannel Configuration Guidelines

If improperly configured, some EtherChannel ports are automatically disabled to avoid network loops
and other problems. Follow these guidelines to avoid configuration problems:
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Do not try to configure more than 48 EtherChannels on the switch.
Configure a PAgP EtherChannel including only NNIs.
Configure a LACP EtherChannel including only NNIs.
Configure all ports in an EtherChannel to operate at the same speeds and duplex modes.
All ports in an EtherChannel must be the same type, either UNI or NNI. You cannot add UNIs to an
EtherChannel containing active NNIs.
On UNIs, the EtherChannel mode must always be configured to on.
Enable all ports in an EtherChannel. A port in an EtherChannel that is disabled by using the
shutdown interface configuration command is treated as a link failure, and its traffic is transferred
to one of the remaining ports in the EtherChannel. UNIs are disabled by default. NNIs are enabled
by default.
When a group is first created, all ports follow the parameters set for the first port to be added to the
group. If you change the configuration of one of these parameters, you must also make the changes
to all ports in the group:
– Allowed-VLAN list
Note Spanning Tree Protocol is only supported on NNIs.
Spanning-tree path cost for each VLAN
–
Spanning-tree port priority for each VLAN
–
Spanning-tree Port Fast setting
–
Do not configure a port to be a member of more than one EtherChannel group.
Do not configure an EtherChannel in both the PAgP and LACP modes. EtherChannel groups running
PAgP and LACP can coexist on the same switch. Individual EtherChannel groups can run either
PAgP or LACP, but they cannot interoperate.
You can only have four NNIs on the switch at the same time; therefore, only four ports in an
EtherChannel can support LACP and PAgP at the same time.
PAgP and LACP are only available on NNIs.
Do not configure a Switched Port Analyzer (SPAN) destination port as part of an EtherChannel.
Do not configure a secure port as part of an EtherChannel or the reverse.
Do not configure a private-VLAN port as part of an EtherChannel.
Do not configure a port that is an active or a not-yet-active member of an EtherChannel as an 802.1x
port. If you try to enable 802.1x on an EtherChannel port, an error message appears, and 802.1x is
not enabled.
If EtherChannels are configured on switch interfaces, remove the EtherChannel configuration from
the interfaces before globally enabling 802.1x on a switch by using the dot1x system-auth-control
global configuration command.
Chapter 31 Configuring EtherChannels
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