Cisco Catalyst 2960 Series, Configuration Manual

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When both interfaces are up, Gi2/0/8 forwards traffic for VLANs 60 and 100 to 120 and Gi2/0/6 forwards
traffic for VLANs 1 to 50.
Switch#
show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet2/0/6
GigabitEthernet2/0/8 Active Up/Backup Standby
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
When a Flex Links interface goes down (LINK_DOWN), VLANs preferred on this interface are moved to
the peer interface of the Flex Links pair. In this example, if interface Gi2/0/6 goes down, Gi2/0/8 carries all
VLANs of the Flex Links pair.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet2/0/6
GigabitEthernet2/0/8 Active Down/Backup Up
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
When a Flex Links interface comes up, VLANs preferred on this interface are blocked on the peer interface
and moved to the forwarding state on the interface that has just come up. In this example, if interface Gi2/0/6
comes up, VLANs preferred on this interface are blocked on the peer interface Gi2/0/8 and forwarded on
Gi2/0/6.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
GigabitEthernet2/0/6
GigabitEthernet2/0/8 Active Up/Backup Standby
Vlans Preferred on Active Interface: 1-50
Vlans Preferred on Backup Interface: 60, 100-120
Switch# show interfaces switchport backup detail
Switch Backup Interface Pairs:
Active Interface Backup Interface State
------------------------------------------------------------------------
FastEthernet1/0/3
FastEthernet1/0/4 Active Down/Backup Up
Vlans Preferred on Active Interface: 1-2,5-4094
Vlans Preferred on Backup Interface: 3-4
Preemption Mode
: off
Bandwidth : 10000 Kbit (Fa1/0/3), 100000 Kbit (Fa1/0/4)
Mac Address Move Update Vlan : auto
Related Topics
Configuring VLAN Load Balancing on Flex Links , on page 383
Flex Links VLAN Load Balancing Configuration Guidelines, on page 379
Restrictions for Configuring Flex Links and MAC Address-Table Move Update, on page 373
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
388
Configuration Examples for Flex Links