Example: Configuring Monitor Link

As shown in Figure 42:

• Device C is a Smart Link device, and Device A, Device B, and Device D are associated devices. Traffic of VLANs 1 through 30 on Device C is dual-uplinked to Device A through a smart link group.

• Implement dual uplink backup on Device C. When the link between Device A and Device B (or Device D) fails, Device C can detect the link fault. It then performs uplink switchover in the smart link group.

For more information about Smart Link, see "Configuring Smart Link."

	IMPORTANT: By default, interfaces on the device are disabled (in ADM or Administratively Down state). To have an interface operate, you must use the undo shutdown command to enable that interface.

1. Configure Device C:

   # Create VLANs 1 through 30.

   <DeviceC> system-view
   [DeviceC] vlan 1 to 30
   

   # Map these VLANs to MSTI 1.

   [DeviceC] stp region-configuration
   [DeviceC-mst-region] instance 1 vlan 1 to 30
   

   # Activate MST region configuration.

   [DeviceC-mst-region] active region-configuration
   [DeviceC-mst-region] quit
   

   # Shut down FortyGigE 1/0/1.

   [DeviceC] interface fortygige 1/0/1
   [DeviceC-FortyGigE1/0/1] shutdown
   

   # Disable the spanning tree feature on the interface.

   [DeviceC-FortyGigE1/0/1] undo stp enable
   

   # Configure the interface as a trunk port.

   [DeviceC-FortyGigE1/0/1] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceC-FortyGigE1/0/1] port trunk permit vlan 1 to 30
   [DeviceC-FortyGigE1/0/1] quit
   

   # Configure FortyGigE 1/0/2 in the same way FortyGigE 1/0/1 is configured.

   [DeviceC] interface fortygige 1/0/2
   [DeviceC-FortyGigE1/0/2] shutdown
   [DeviceC-FortyGigE1/0/2] undo stp enable
   [DeviceC-FortyGigE1/0/2] port link-type trunk
   [DeviceC-] port trunk permit vlan 1 to 30
   [DeviceC-FortyGigE1/0/2] quit
   

   # Create smart link group 1, and configure all the VLANs mapped to MSTI 1 as the protected VLANs for smart link group 1.

   [DeviceC] smart-link group 1
   [DeviceC-smlk-group1] protected-vlan reference-instance 1
   

   # Configure FortyGigE 1/0/1 as the primary port and FortyGigE 1/0/2 as the secondary port for smart link group 1.

   [DeviceC-smlk-group1] port fortygige 1/0/1 primary
   [DeviceC-smlk-group1] port fortygige 1/0/2 secondary
   

   # Enable the smart link group to transmit flush messages.

   [DeviceC-smlk-group1] flush enable
   [DeviceC-smlk-group1] quit
   

   # Bring up FortyGigE 1/0/1 and FortyGigE 1/0/2.

   [DeviceC] interface fortygige 1/0/1
   [DeviceC-FortyGigE1/0/1] undo shutdown
   [DeviceC-FortyGigE1/0/1] quit
   [DeviceC] interface fortygige 1/0/2
   [DeviceC-FortyGigE1/0/2] undo shutdown
   [DeviceC-FortyGigE1/0/2] quit
   

2. Configure Device A:

   # Create VLANs 1 through 30.

   <DeviceA> system-view
   [DeviceA] vlan 1 to 30
   

   # Configure FortyGigE 1/0/1 as a trunk port.

   [DeviceA] interface fortygige 1/0/1
   [DeviceA-FortyGigE1/0/1] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceA-FortyGigE1/0/1] port trunk permit vlan 1 to 30
   

   # Enable flush message receiving on the interface.

   [DeviceA-FortyGigE1/0/1] smart-link flush enable
   [DeviceA-FortyGigE1/0/1] quit
   

   # Configure in the same way FortyGigE 1/0/1 is configured.

   [DeviceA] interface fortygige 1/0/2
   [DeviceA-FortyGigE1/0/2] port link-type trunk
   [DeviceA-FortyGigE1/0/2] port trunk permit vlan 1 to 30
   [DeviceA-FortyGigE1/0/2] smart-link flush enable
   [DeviceA-FortyGigE1/0/2] quit
   

3. Configure Device B:

   # Create VLANs 1 through 30.

   <DeviceB> system-view
   [DeviceB] vlan 1 to 30
   

   # Configure as a trunk port.

   [DeviceB] interface fortygige 1/0/1
   [DeviceB-FortyGigE1/0/1] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceB-FortyGigE1/0/1] port trunk permit vlan 1 to 30
   

   # Enable flush message receiving on the interface.

   [DeviceB-FortyGigE1/0/1] smart-link flush enable
   [DeviceB-FortyGigE1/0/1] quit
   

   # Disable the spanning tree feature on FortyGigE 1/0/2.

   [DeviceB] interface 
   [DeviceB-FortyGigE1/0/2] undo stp enable
   

   # Configure the interface as a trunk port.

   [DeviceB-FortyGigE1/0/2] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceB-FortyGigE1/0/2] port trunk permit vlan 1 to 30
   

   # Enable flush message receiving on the interface.

   [DeviceB-] smart-link flush enable
   [DeviceB-FortyGigE1/0/2] quit
   

   # Create monitor link group 1.

   [DeviceB] monitor-link group 1
   

   # Configure FortyGigE 1/0/1 as an uplink interface for monitor link group 1.

   [DeviceB-mtlk-group1] port fortygige 1/0/1 uplink
   

   # Configure FortyGigE 1/0/2 as a downlink interface for monitor link group 1.

   [DeviceB-mtlk-group1] port fortygige 1/0/2 downlink
   [DeviceB-mtlk-group1] quit
   

4. Configure Device D:

   # Create VLANs 1 through 30.

   <DeviceD> system-view
   [DeviceD] vlan 1 to 30
   

   # Configure FortyGigE 1/0/1 as a trunk port.

   [DeviceD] interface fortygige 1/0/1
   [DeviceD-FortyGigE1/0/1] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceD-FortyGigE1/0/1] port trunk permit vlan 1 to 30
   

   # Enable flush message receiving on the interface.

   [DeviceD-] smart-link flush enable
   [DeviceD-FortyGigE1/0/1] quit
   

   # Disable the spanning tree feature on FortyGigE 1/0/2.

   [DeviceD] interface fortygige 1/0/2
   [DeviceD-FortyGigE1/0/2] undo stp enable
   

   # Configure the interface as a trunk port.

   [DeviceD-] port link-type trunk
   

   # Assign the interface to VLANs 1 through 30.

   [DeviceD-FortyGigE1/0/2] port trunk permit vlan 1 to 30
   

   # Enable flush message receiving on the interface.

   [DeviceD-FortyGigE1/0/2] smart-link flush enable
   [DeviceD-FortyGigE1/0/2] quit
   

   # Create monitor link group 1.

   [DeviceD] monitor-link group 1
   

   # Configure FortyGigE 1/0/1 as an uplink interface for monitor link group 1.

   [DeviceD-mtlk-group1] port fortygige 1/0/1 uplink
   

   # Configure as a downlink interface for monitor link group 1.

   [DeviceD-mtlk-group1] port fortygige 1/0/2 downlink
   [DeviceD-mtlk-group1] quit
   

# When on Device A goes down because of a link fault, verify information about monitor link group 1 on Device B.

[DeviceB] display monitor-link group 1
Monitor link group 1 information:
  Group status     : UP
  Downlink up-delay: 0(s)
  Last-up-time     : 16:38:26 2012/4/21
  Last-down-time   : 16:37:20 2012/4/21
  Up-port-threshold: 1

  Member                    Role       Status
  --------------------------------------------
  FGE1/0/1                  UPLINK     UP
  FGE1/0/2                  DOWNLINK   UP

# Verify information about monitor link group 1 on Device D.

[DeviceD] display monitor-link group 1
Monitor link group 1 information:
  Group status     : DOWN
  Downlink up-delay: 0(s)
  Last-up-time     : 16:37:20 2012/4/21
  Last-down-time   : 16:38:26 2012/4/21
  Up-port-threshold: 1

  Member                    Role       Status
  --------------------------------------------
  FGE1/0/1                  UPLINK     DOWN
  FGE1/0/2                  DOWNLINK   DOWN