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Cisco ME 3400 EthernetAccess Switch SoftwareConfiguration Guide
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Chapter17 Configuring Flex Link s Configuring Flex Links
•A backup link does not have to be the same type (Fast Ethernet, Gigabi t E the rne t, or p or t ch an nel)
as the active link. However, you should conf igure both Fle x Links with similar characteristics so tha t
there are no loops or changes in behavior if the standby link begins to forward traffic.
•STP is disabled on Flex Link ports. If STP is configured on the switch, Flex Links do not participate
in STP in all VLANs in which STP is configured. With STP not running, be sure tha t t here are no
loops in the configured topology.\
Note STP is available only on NNIs.
Configuring Flex Links
Beginning in privileged EXEC mode, follow these steps to configure a pair of Flex Li nks :
This example shows how to configure an interface with a backup interface and to verify the
configuration:
Switch# configure terminal
Switch(conf)# interface fastethernet0/1
Switch(conf-if)# no shutdown
Switch(conf-if)# switchport backup interface fastethernet0/2
Switch(conf-if)# end
Switch# show interface switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------------------------
FastEthernet0/1 FastEthernet0/2 Active Up/Backup Standby
FastEthernet0/3 FastEthernet0/4 Active Up/Backup Standby
Port-channel1 GigabitEthernet0/1 Active Up/Backup Standby
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Specify the interface, and enter interface configuration
mode. The interface can be a physical Layer 2 interface or
a port channel (logical interface). The port-channel range
is 1 to 48.
Step3 no shutdown Enable the port, if necessary. By default, UNIs are
disabled, and NNIs are enabled.
Step4 switchport backup interface interface-id Configure a physical Layer 2 interface (or port channel)
as part of a Flex Link pair with the interface. When one
link is forwarding traffic, the other interface is in standb y
mode.
Step5 end Return to privileged EXEC mode.
Step6 show interface [interface-id] switchport backup Verify the configuration.
Step7 copy running-config startup config (Optional) Save your entries in the switch startup
configuration file.