Example for Configuring OSPFv3 DR Election

This section describes how to set the DR priority on an interface for DR election on a broadcast network.

Networking Requirements

On the network shown in Figure 1, Device A has the highest priority (100) on the network and is elected as the DR; Device C has the second highest priority and is elected as the BDR. Device B has the priority of 0 and cannot be elected as a DR or a BDR; no priority is configured for Device D, and therefore, and Device D uses the default value (1).

Figure 1 Networking for configuring OSPFv3 DR election

Interface 1 in this example represents GE 0/1/0.

Configuration Notes

Reconfiguring the DR priority for the router does not change the DR or BDR on a network. You can use either of the following methods to re-elect a DR or BDR. However, the following methods will disconnect OSPFv3 neighbors. Therefore, use the following methods only when necessary.

Restart the OSPFv3 processes on all routers.
Configure the shutdown and undo shutdown commands on the interfaces where the OSPFv3 neighbor relationships are established.

Configuration Roadmap

Configure the router ID on each router, enable OSPFv3, and specify the network segment.
Check the DR/BDR status with the default priority.
Configure the DR priority on the interface and check the DR/BDR status.

Data Preparation

To complete the configuration, you need the following data:

Router ID (1.1.1.1) and priority (100) of Device A
Router ID (2.2.2.2) and priority (0) of Device B
Router ID (3.3.3.3) and priority (2) of Device C
Router ID (4.4.4.4) and priority (1) of Device D

Procedure

Assign an IPv6 address to each interface.
For configuration details, see Configuration Files in this section.

Configure basic OSPFv3 functions.

# Configure DeviceA, enable OSPFv3, and set its router ID to 1.1.1.1.

[*DeviceA] ospfv3
[*DeviceA-ospfv3-1] router-id 1.1.1.1
[*DeviceA-ospfv3-1] quit
[*DeviceA] interface gigabitethernet 0/1/0
[*DeviceA-GigabitEthernet0/1/0] ospfv3 1 area 0
[*DeviceA-GigabitEthernet0/1/0] quit
[*DeviceA] commit

# Configure DeviceB, enable OSPFv3, and set its router ID to 2.2.2.2.

[*DeviceB] ospfv3
[*DeviceB-ospfv3-1] router-id 2.2.2.2
[*DeviceB-ospfv3-1] quit
[*DeviceB] interface gigabitethernet 0/1/0
[*DeviceB-GigabitEthernet0/1/0] ospfv3 1 area 0
[*DeviceB-GigabitEthernet0/1/0] quit
[*DeviceB] commit

# Configure DeviceC, enable OSPFv3, and set its router ID to 3.3.3.3.

[*DeviceC] ospfv3
[*DeviceC-ospfv3-1] router-id 3.3.3.3
[*DeviceC-ospfv3-1] quit
[*DeviceC] interface gigabitethernet 0/1/0
[*DeviceC-GigabitEthernet0/1/0] ospfv3 1 area 0
[*DeviceC-GigabitEthernet0/1/0] quit
[*DeviceC] commit

# Configure DeviceD, enable OSPFv3, and set its router ID to 4.4.4.4.

[*DeviceD] ospfv3
[*DeviceD-ospfv3-1] router-id 4.4.4.4
[*DeviceD-ospfv3-1] quit
[*DeviceD] interface gigabitethernet 0/1/0
[*DeviceD-GigabitEthernet0/1/0] ospfv3 1 area 0
[*DeviceD-GigabitEthernet0/1/0] quit
[*DeviceD] commit

# Display the neighbors of DeviceA. You can view the DR priority and the neighbor status. By default, the DR priority is 1. DeviceD is the DR, and DeviceC is the BDR.

The router with the greatest router ID is the DR when routers have the same priority. If an Ethernet interface of the router becomes a DR, the other broadcast interfaces of the router have the highest priority in DR election.

[~DeviceA] display ospfv3 peer
    OSPFv3 Process (1)


    OSPFv3 Area (0.0.0.0)
    Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
    2.2.2.2       1   2-Way/DROther    00:00:32    GE0/1/0         0
    3.3.3.3       1   Full/Backup      00:00:36    GE0/1/0         0
    4.4.4.4       1   Full/DR          00:00:38    GE0/1/0         0

# Display the neighbors of DeviceD. The command output shows that all neighbors of DeviceD are in the Full state.

[~DeviceD] display ospfv3 peer
    OSPFv3 Process (1)


    OSPFv3 Area (0.0.0.0)
    Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
    1.1.1.1       1   Full/DROther     00:00:32    GE0/1/0         0
    2.2.2.2       1   Full/DROther     00:00:35    GE0/1/0         0
    3.3.3.3       1   Full/Backup      00:00:30    GE0/1/0         0

Set the DR priority of the interface.

# Set the DR priority of DeviceA to 100.

[~DeviceA] interface gigabitethernet 0/1/0
[~DeviceA-GigabitEthernet0/1/0] ospfv3 dr-priority 100
[*DeviceA-GigabitEthernet0/1/0] quit
[*DeviceA] commit

# Set the DR priority of DeviceB to 0.

[~DeviceB] interface gigabitethernet 0/1/0
[~DeviceB-GigabitEthernet0/1/0] ospfv3 dr-priority 0
[*DeviceB-GigabitEthernet0/1/0] quit
[*DeviceB] commit

# Set the DR priority of DeviceC to 2.

[~DeviceC] interface gigabitethernet 0/1/0
[~DeviceC-GigabitEthernet0/1/0] ospfv3 dr-priority 2
[*DeviceC-GigabitEthernet0/1/0] quit
[*DeviceC] commit

# Display the neighbors of DeviceA. The command output shows that the DR priority is updated and that the DR and BDR remain unchanged.

[~DeviceA] display ospfv3 peer
    OSPFv3 Process (1)


    OSPFv3 Area (0.0.0.0)
    Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
    2.2.2.2       0   2-Way/DROther    00:00:34    GE0/1/0         0
    3.3.3.3       2   Full/Backup      00:00:38    GE0/1/0         0
    4.4.4.4       1   Full/DR          00:00:31    GE0/1/0         0

# Display the neighbors of DeviceD. The command output shows that DeviceD remains the DR.

[~DeviceD] display ospfv3 peer
    OSPFv3 Process (1)


    OSPFv3 Area (0.0.0.0)
    Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
    1.1.1.1      100   Full/DROther     00:00:36    GE0/1/0         0
    2.2.2.2      0   Full/DROther       00:00:30    GE0/1/0         0
    3.3.3.3      2   Full/Backup        00:00:36    GE0/1/0         0

Re-elect the DR/BDR.
# Restart all routers (or run the shutdown and undo shutdown commands on the interface that establishes the OSPFv3 neighbor relationship), and re-elect the DR/BDR.

Verify the configuration.

# Display the neighbors of DeviceA. The command output shows that DeviceC is the BDR.

[~DeviceA] display ospfv3 peer
   OSPFv3 Process (1)


   OSPFv3 Area (0.0.0.0)
   Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
   2.2.2.2       0   Full/DROther     00:00:31    GE0/1/0         0
   3.3.3.3       2   Full/Backup      00:00:36    GE0/1/0         0
   4.4.4.4       1   Full/DROther     00:00:39    GE0/1/0         0

# Display the neighbors of DeviceD. The command output shows that DeviceA is the DR.

[~DeviceD] display ospfv3 peer
   OSPFv3 Process (1)


   OSPFv3 Area (0.0.0.0)
   Neighbor ID     Pri   State            Dead Time   Interface  Instance ID
   1.1.1.1       100   Full/DR        00:00:39    GE0/1/0         0
   2.2.2.2       0   2-Way/DROther    00:00:35    GE0/1/0         0
   3.3.3.3       2   Full/Backup      00:00:39    GE0/1/0         0

Configuration Files

DeviceA configuration file

#
 sysname DeviceA
#
interface GigabitEthernet0/1/0
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:1001::1/96
 ospfv3 1 area 0.0.0.0
 ospfv3 dr-priority 100
#
ospfv3 1
 router-id 1.1.1.1
 area 0.0.0.0
#
return

DeviceB configuration file

#
 sysname DeviceB
#
interface GigabitEthernet0/1/0
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:1001::2/96
 ospfv3 1 area 0.0.0.0
 ospfv3 dr-priority 0
#
ospfv3 1
 router-id 2.2.2.2
 area 0.0.0.0
#
return

DeviceC configuration file

#
 sysname DeviceC
#
interface GigabitEthernet0/1/0
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:1001::3/96
 ospfv3 1 area 0.0.0.0
 ospfv3 dr-priority 2
#
ospfv3 1
 router-id 3.3.3.3
 area 0.0.0.0
#
return

DeviceD configuration file

#
 sysname DeviceD
#
interface GigabitEthernet0/1/0
 undo shutdown
 ipv6 enable
 ipv6 address 2001:db8:1001::4/96
 ospfv3 1 area 0.0.0.0
#
ospfv3 1
 router-id 4.4.4.4
 area 0.0.0.0
#
return