Manually shutting down unidirectional links

As shown in Figure 11, Device A and Device B are connected through two fiber pairs.

Configure DLDP to detect unidirectional links. When a unidirectional link is detected, the administrator must manually shut down the port.

1. Configure Device A:

   # Enable DLDP globally.

   <DeviceA> system-view
   [DeviceA] dldp enable
   

   # Configure GigabitEthernet 1/0/1 to operate in full duplex mode and at 1000 Mbps, and enable DLDP on the port.

   [DeviceA] interface gigabitethernet 1/0/1
   [DeviceA-GigabitEthernet1/0/1] duplex full
   [DeviceA-GigabitEthernet1/0/1] speed 1000
   [DeviceA-GigabitEthernet1/0/1] dldp enable
   [DeviceA-GigabitEthernet1/0/1] quit
   

   # Configure GigabitEthernet 1/0/2 to operate in full duplex mode and at 1000 Mbps, and enable DLDP on the port.

   [DeviceA] interface gigabitethernet 1/0/2
   [DeviceA-GigabitEthernet1/0/2] duplex full
   [DeviceA-GigabitEthernet1/0/2] speed 1000
   [DeviceA-GigabitEthernet1/0/2] dldp enable
   [DeviceA-GigabitEthernet1/0/2] quit
   

   # Set the port shutdown mode to manual.

   [DeviceA] dldp unidirectional-shutdown manual
   

2. Configure Device B:

   # Enable DLDP globally.

   <DeviceB> system-view
   [DeviceB] dldp global enable
   

   # Configure GigabitEthernet 1/0/1 to operate in full duplex mode and at 1000 Mbps, and enable DLDP on it.

   [DeviceB] interface gigabitethernet 1/0/1
   [DeviceB-GigabitEthernet1/0/1] duplex full
   [DeviceB-GigabitEthernet1/0/1] speed 1000
   [DeviceB-GigabitEthernet1/0/1] dldp enable
   [DeviceB-GigabitEthernet1/0/1] quit
   

   # Configure GigabitEthernet 1/0/2 to operate in full duplex mode and at 1000 Mbps, and enable DLDP on it.

   [DeviceB] interface gigabitethernet 1/0/2
   [DeviceB-GigabitEthernet1/0/2] duplex full
   [DeviceB-GigabitEthernet1/0/2] speed 1000
   [DeviceB-GigabitEthernet1/0/2] dldp enable
   [DeviceB-GigabitEthernet1/0/2] quit
   

   # Set the port shutdown mode to manual.

   [DeviceB] dldp unidirectional-shutdown manual
   

3. Verify the configuration:

   # Display the DLDP configuration globally and on all the DLDP-enabled ports of Device A.

   [DeviceA] display dldp
    DLDP global status: Enabled
    DLDP advertisement interval: 5s
    DLDP authentication-mode: None
    DLDP unidirectional-shutdown mode: Manual
    DLDP delaydown-timer value: 1s
    Number of enabled ports: 2
   
   Interface GigabitEthernet1/0/1
    DLDP port state: Bidirectional
    Number of the port’s neighbors: 1
     Neighbor MAC address: 0023-8956-3600
     Neighbor port index: 1
     Neighbor state: Confirmed
     Neighbor aged time: 11s
   
   Interface GigabitEthernet1/0/2
    DLDP port state: Bidirectional
    Number of the port’s neighbors: 1
     Neighbor MAC address: 0023-8956-3600
     Neighbor port index: 2
     Neighbor state: Confirmed
     Neighbor aged time: 12s
   

   The output shows that both GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 are in bidirectional state, which means both links are bidirectional.

   # Enable the monitoring of logs on the current terminal on Device A. Set the lowest level of the logs that can be output to the current terminal to 6.

   [DeviceA] quit
   <DeviceA> terminal monitor
   <DeviceA> terminal logging level 6
   

   The following log information is displayed on Device A:

   <DeviceA>%Jul 12 08:29:17:786 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/1 link status is DOWN.
   %Jul 12 08:29:17:787 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/1 is DOWN.
   %Jul 12 08:29:17:800 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/2 link status is DOWN.
   %Jul 12 08:29:17:800 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/2 is DOWN.
   %Jul 12 08:29:25:004 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/1 link status is UP.
   %Jul 12 08:29:25:005 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/1 is UP.
   %Jul 12 08:29:25:893 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/2 link status is UP.
   %Jul 12 08:29:25:894 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/2 is UP.
   

   The output shows that the port status and link status of both GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 are down and then up.

   # Display the DLDP configuration globally and of all the DLDP-enabled ports.

   <DeviceA> display dldp
    DLDP global status: Enabled
    DLDP advertisement interval: 5s
    DLDP authentication-mode: None
    DLDP unidirectional-shutdown mode: Manual
    DLDP delaydown-timer value: 1s
    Number of enabled ports: 2
   
   Interface GigabitEthernet1/0/1
    DLDP port state: Unidirectional
    Number of the port’s neighbors: 0 (Maximum number ever detected: 1)
   
   Interface GigabitEthernet1/0/2
    DLDP port state: Unidirectional
    Number of the port’s neighbors: 0 (Maximum number ever detected: 1)
   

   The output shows that the DLDP port status of both GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 is unidirectional. DLDP detects unidirectional links on the two ports but does not shut them down.

   The unidirectional links are caused by cross-connected fibers. Manually shut down the two ports:

   # Shut down GigabitEthernet 1/0/1.

   <DeviceA> system-view
   [DeviceA] interface gigabitethernet 1/0/1
   [DeviceA-GigabitEthernet1/0/1] shutdown
   

   The following log information is displayed on Device A:

   [DeviceA-GigabitEthernet1/0/1]%Jul 12 08:34:23:717 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/1 link status is DOWN.
   %Jul 12 08:34:23:718 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/1 is DOWN.
   %Jul 12 08:34:23:778 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/2 link status is DOWN.
   %Jul 12 08:34:23:779 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/2 is DOWN.
   

   The output shows that the port status and link status of both GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 are now down.

   # Shut down GigabitEthernet 1/0/2.

   [DeviceA-GigabitEthernet1/0/1] quit
   [DeviceA] interface gigabitethernet 1/0/2
   [DeviceA-GigabitEthernet1/0/2] shutdown
   

   Correct the fiber connections and bring up the two ports:

   # Bring up GigabitEthernet 1/0/2.

   [DeviceA-GigabitEthernet1/0/2] undo shutdown
   

   The following log information is displayed on Device A:

   [DeviceA-GigabitEthernet1/0/2]%Jul 12 08:46:17:677 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/2 link status is UP.
   %Jul 12 08:46:17:678 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/2 is UP.
   %Jul 12 08:46:17:959 2012 DeviceA DLDP/6/DLDP_NEIGHBOR_CONFIRMED: A neighbor was confirmed on interface GigabitEthernet1/0/2. The neighbor's system MAC is 0023-8956-3600, and the port index is 2.
   %Jul 12 08:46:17:959 2012 DeviceA DLDP/6/DLDP_LINK_BIDIRECTIONAL: DLDP detected a bidirectional link on interface GigabitEthernet1/0/2.
   

   The output shows that the port status and link status of GigabitEthernet 1/0/2 are now up and its DLDP neighbors are determined.

   # Bring up GigabitEthernet 1/0/1.

   [DeviceA-GigabitEthernet1/0/2] quit
   [DeviceA] interface gigabitethernet 1/0/1
   [DeviceA-GigabitEthernet1/0/1] undo shutdown
   

   The following log information is displayed on Device A:

   [DeviceA-GigabitEthernet1/0/1]%Jul 12 08:48:25:952 2012 DeviceA IFNET/3/PHY_UPDOWN: GigabitEthernet1/0/1 link status is UP.
   %Jul 12 08:48:25:952 2012 DeviceA DLDP/6/DLDP_NEIGHBOR_CONFIRMED: A neighbor was confirmed on interface GigabitEthernet1/0/1. The neighbor's system MAC is 0023-8956-3600, and the port index is 1.
   %Jul 12 08:48:25:953 2012 DeviceA IFNET/5/LINK_UPDOWN: Line protocol on the interface GigabitEthernet1/0/1 is UP.
   %Jul 12 08:48:25:953 2012 DeviceA DLDP/6/DLDP_LINK_BIDIRECTIONAL: DLDP detected a bidirectional link on interface GigabitEthernet1/0/1.
   

   The output shows that the port status and link status of GigabitEthernet 1/0/1 are now up and its DLDP neighbors are determined.