Cisco Catalyst 3750 Metro Command Reference Manual page 504

show interfaces
When a Flex Link interface goes down (LINK_DOWN), VLANs preferred on this interface are moved
to the peer interface of the Flex Link pair. In this example, if interface Gi1/0/6 goes down, Gi1/0/8 carries
all VLANs of the Flex Link pair.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
GigabitEthernet1/0/6
Vlans on Interface Gi 1/0/6:
Vlans on Interface Gi 1/0/8: 1-50, 60, 100-120
When a Flex Link 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 Gi1/0/6 comes up, then VLANs preferred on this interface are blocked on the peer interface
Gi1/0/8 and forwarded on Gi1/0/6.
Switch# show interfaces switchport backup
Switch Backup Interface Pairs:
Active Interface
------------------------------------------------------------------------
GigabitEthernet1/0/6
Vlans on Interface Gi 1/0/6: 1-50
Vlans on Interface Gi 1/0/8: 60, 100-120
This is an example of output from the show interfaces interface-id trunk command. It displays trunking
information for the port.
Switch# show interfaces gigabitethernet1/0/1 trunk
Port
Gi1/0/1
Port
Gi1/0/1
Port
Gi1/0/1
Port
Gi1/0/1
Related Commands Command
switchport access
switchport block
switchport backup interface
switchport mode
switchport protected
switchport trunk
Catalyst 3750 Metro Switch Command Reference
2-476
Backup Interface
GigabitEthernet1/0/8
Backup Interface
GigabitEthernet1/0/8
Mode Encapsulation
auto negotiate
Vlans allowed on trunk
1-4094
Vlans allowed and active in management domain
1-4
Vlans in spanning tree forwarding state and not pruned
1-4
Description
Configures a port as a static-access or a dynamic-access port.
Blocks unknown unicast or multicast traffic on an interface.
Configures Flex Links, a pair of Layer 2 interfaces that provide mutual
backup.
Configures the VLAN membership mode of a port.
Isolates unicast, multicast, and broadcast traffic at Layer 2 from other
protected ports on the same switch.
pruning Configures the VLAN pruning-eligible list for ports in trunking mode.
Chapter 2 Catalyst 3750 Metro Switch Cisco IOS Commands
State
Active Down/Backup Up
State
Active Up/Backup Up
Status Native vlan
trunking 1
OL-9645-10