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:
•
Do not try to configure more than 48 EtherChannels on the switch or switch stack.
Do not try to configure more than 48 EtherChannels on the switch or switch stack.
•Configure a PAgP EtherChannel with up to eight Ethernet ports of the same type.
Configure a PAgP EtherChannel with up to eight Ethernet ports of the same type.
•Configure
a LACP EtherChannel with up to16 Ethernet ports of the same type. Up to
eight ports can be active, and up to eight ports can be in standby
mode.
Configure
a LACP EtherChannel with up to16 Ethernet ports of the same type. Up to
eight ports can be active, and up to eight ports can be in standby
mode.
•Configure all ports in an EtherChannel to operate at the same speeds and duplex modes.
Configure all ports in an EtherChannel to operate at the same speeds and duplex modes.
•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.
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.
•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:
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
Allowed-VLAN list
–Spanning-tree path cost for each VLAN
Spanning-tree path cost for each VLAN
–Spanning-tree port priority for each VLAN
Spanning-tree port priority for each VLAN
–Spanning-tree Port Fast setting
Spanning-tree Port Fast setting
•Do not configure a port to be a member of more than one EtherChannel group.
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
or on different switches in the stack. Individual EtherChannel groups
can run either PAgP or LACP, but they cannot interoperate.
Do
not configure an EtherChannel in both the PAgP and LACP modes.
EtherChannel groups running PAgP and LACP can coexist on the same switch
or on different switches in the stack. Individual EtherChannel groups
can run either PAgP or LACP, but they cannot interoperate.
•Do not configure a Switched Port Analyzer (SPAN) destination port as part of an EtherChannel.
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 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 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 IEEE 802.1x port. If you try to enable IEEE 802.1x
on an EtherChannel port, an error message appears, and IEEE 802.1x is
not enabled.
Do
not configure a port that is an active or a not-yet-active member of an
EtherChannel as an IEEE 802.1x port. If you try to enable IEEE 802.1x
on an EtherChannel port, an error message appears, and IEEE 802.1x is
not enabled.
•If
EtherChannels are configured on switch interfaces, remove the
EtherChannel configuration from the interfaces before globally enabling
IEEE 802.1x on a switch by using the dot1x system-auth-control global configuration command.
If
EtherChannels are configured on switch interfaces, remove the
EtherChannel configuration from the interfaces before globally enabling
IEEE 802.1x on a switch by using the dot1x system-auth-control global configuration command.
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.
Assign
all ports in the EtherChannel to the same VLAN, or configure them as
trunks. Ports with different native VLANs cannot form an EtherChannel.
–If
you configure an EtherChannel from trunk ports, verify that the
trunking mode (ISL or IEEE 802.1Q) is the same on all the trunks.
Inconsistent trunk modes on EtherChannel ports can have unexpected
results.
If
you configure an EtherChannel from trunk ports, verify that the
trunking mode (ISL or IEEE 802.1Q) 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 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.
An
EtherChannel supports the same allowed range of VLANs on all the ports
in a trunking 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.
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.
Note Layer 3 EtherChannels are not supported on switches running the LAN base feature set.
Layer 3 EtherChannels are not supported on switches running the LAN base feature set.
•For
cross-stack EtherChannel configurations, ensure that all ports targeted
for the EtherChannel are either configured for LACP or are manually
configured to be in the channel group using the channel-group channel-group-number mode on interface configuration command. The PAgP protocol is not supported on cross- stack EtherChannels.
For
cross-stack EtherChannel configurations, ensure that all ports targeted
for the EtherChannel are either configured for LACP or are manually
configured to be in the channel group using the channel-group channel-group-number mode on interface configuration command. The PAgP protocol is not supported on cross- stack EtherChannels.
•If cross-stack EtherChannel is configured and the switch stack partitions, loops and forwarding misbehaviors can occur.
If cross-stack EtherChannel is configured and the switch stack partitions, loops and forwarding misbehaviors can occur. |
Default
EtherChannel Configuration
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Channel groups
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Port-channel logical interface
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PAgP mode
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PAgP learn method
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Aggregate-port learning on all ports.
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PAgP priority
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128 on all ports.
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LACP mode
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LACP learn method
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Aggregate-port learning on all ports.
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LACP port priority
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32768 on all ports.
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LACP system priority
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32768
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LACP system ID
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LACP system priority and the switch or stack MAC address.
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Load-balancing
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Load distribution on the switch is based on the source-MAC
address of the incoming packet.
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Ref link : http://www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/12.2_53_se/configuration/guide/swethchl.html#wp1275881
