Example for Configuring OSPFv3 Route Summarization on an ABR

This section provides an example showing how to configure OSPFv3 route summarization on an ABR.

Networking Requirements

Routes with the same IPv6 prefix can be summarized into one route. On a large-scale OSPFv3 network, route lookup may slow down because of the large size of the routing table. To reduce the routing table size and simplify management, configure route summarization. With route summarization, if a link connected to a device within an IPv6 address range that has been summarized alternates between Up and Down, the link status change is not advertised to the devices beyond the IPv6 address range. This prevents route flapping and improves network stability.

In Figure 1, all devices run OSPFv3. To reduce the routing table size, simplify route management, and improve network stability, it is required that the ABR be configured to summarize the routes with the same prefix (2001:DB8::) into route 2001:DB8::/32 and advertise it only to area 0.

Figure 1 Example for configuring OSPFv3 route summarization on an ABR

Interfaces 1 through 3 in this example represent GE 0/1/0, GE 0/1/8, and GE 0/1/16, respectively.

Configuration Roadmap

The configuration roadmap is as follows:

Assign an IP address to each interface to ensure that devices on the network can communicate with each other.
Configure basic OSPFv3 functions on all devices.
Configure OSPFv3 route summarization on the ABR.

Data Preparation

To complete the configuration, you need the following data:

Areas 0 and 1
Router ID (1.1.1.1) of Device B
Router ID (2.2.2.2) of the ABR
Router ID (3.3.3.3) of Device A
Router ID (4.4.4.4) of Device C

Procedure

Configure an IP address for each interface. For configuration details, see "Configuration Files" in this section.

Configure basic OSPFv3 functions.

# Configure Device A.

[~DeviceA] ospfv3 1
[*DeviceA-ospfv3-1] router-id 3.3.3.3
[*DeviceA-ospfv3-1] area 0.0.0.1
[*DeviceA-ospfv3-1-area-0.0.0.1] quit
[*DeviceA-ospfv3-1] quit
[*DeviceA] commit
[~DeviceA] interface gigabitethernet0/1/8
[~DeviceA-GigabitEthernet0/1/8] ospfv3 1 area 1
[*DeviceA-GigabitEthernet0/1/8] quit
[*DeviceA] commit

# Configure Device B.

[~DeviceB] ospfv3 1
[*DeviceB-ospfv3-1] router-id 1.1.1.1
[*DeviceB-ospfv3-1] area 0.0.0.0
[*DeviceB-ospfv3-1-area-0.0.0.0] quit
[*DeviceB-ospfv3-1] quit
[*DeviceB] commit
[~DeviceB] interface gigabitethernet0/1/0
[~DeviceB-GigabitEthernet0/1/0] ospfv3 1 area 0
[*DeviceB-GigabitEthernet0/1/0] quit
[*DeviceB] commit

# Configure Device C.

[~DeviceC] ospfv3 1
[*DeviceC-ospfv3-1] router-id 4.4.4.4
[*DeviceC-ospfv3-1] area 0.0.0.1
[*DeviceC-ospfv3-1-area-0.0.0.1] quit
[*DeviceC-ospfv3-1] quit
[*DeviceC] commit
[~DeviceC] interface gigabitethernet0/1/16
[~DeviceC-GigabitEthernet0/1/16] ospfv3 1 area 1
[*DeviceC-GigabitEthernet0/1/16] quit
[*DeviceC] commit

# Configure the ABR.

[~ABR] ospfv3 1
[*ABR-ospfv3-1] router-id 2.2.2.2
[*ABR-ospfv3-1] area 0.0.0.0
[*ABR-ospfv3-1-area-0.0.0.0] quit
[*ABR-ospfv3-1] area 0.0.0.1
[*ABR-ospfv3-1-area-0.0.0.1] quit
[*ABR-ospfv3-1] quit
[*ABR] commit
[~ABR] interface gigabitethernet0/1/0
[~ABR-GigabitEthernet0/1/0] ospfv3 1 area 0
[*ABR-GigabitEthernet0/1/0] quit
[*ABR] interface gigabitethernet0/1/8
[*ABR-GigabitEthernet0/1/8] ospfv3 1 area 1
[*ABR-GigabitEthernet0/1/8] quit
[*ABR] interface gigabitethernet0/1/16
[*ABR-GigabitEthernet0/1/16] ospfv3 1 area 1
[*ABR-GigabitEthernet0/1/16] quit
[*ABR] commit

# Run the display ospfv3 peer command to check whether the ABR establishes an OSPFv3 neighbor relationship with Device A, Device B, and Device C. The following example uses the command output on the ABR:

[~ABR] 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/DR          00:00:35   GE0/1/0               0       
OSPFv3 Area (0.0.0.1)
Neighbor ID      Pri State            Dead Time  Interface          Instance ID
4.4.4.4            1 Full/Backup      00:00:40   GE0/1/16               0       
3.3.3.3            1 Full/Backup      00:00:31   GE0/1/8               0

# Run the display ospfv3 lsdb command on the ABR to check the OSPFv3 LSDB information. The Inter-area-prefix LSA field in the LSDB of area 1 shows that no summarization is performed for the routes. Therefore, the routes advertised to area 0 are not summarized.

[~ABR] display ospfv3 lsdb

           OSPFv3 Router with ID (2.2.2.2) (Process 1)

               Link-LSA (Interface GE0/1/0)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.18        1.1.1.1          1740  0x80000010 0x8b9b          1
0.0.0.18        2.2.2.2          1684  0x80000010 0xc249          1

               Link-LSA (Interface GE0/1/16)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.19        2.2.2.2          154   0x80000002 0x33e2          1
0.0.0.19        4.4.4.4          75    0x80000002 0xf927          1

               Link-LSA (Interface GE0/1/8)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.20        2.2.2.2          383   0x8000000e 0x306           1
0.0.0.11        3.3.3.3          232   0x8000000e 0xc146          1

               Router-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum    Link
0.0.0.1         1.1.1.1          1682  0x80000010 0xb42e      1
0.0.0.1         2.2.2.2          384   0x80000014 0x9148      1

               Network-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.18        1.1.1.1          1682  0x8000000f 0xb741
                                Inter-Area-Prefix-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.2         2.2.2.2          154   0x80000001 0x9071 0.0.0.3         2.2.2.2          1726  0x8000000a 0xf315
                                Intra-Area-Prefix-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum   Prefix Reference      
0.0.0.1         1.1.1.1          1682  0x8000000f 0xba9        1 Network-LSA    
                                Router-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum    Link
0.0.0.1         2.2.2.2          70    0x8000000f 0xa0f4      2
0.0.0.1         3.3.3.3          226   0x8000000e 0x904d      1
0.0.0.1         4.4.4.4          71    0x80000002 0xe8f5      1
                                Network-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.19        2.2.2.2          70    0x80000001 0x22d3
0.0.0.20        2.2.2.2          225   0x8000000d 0xdd0f
                                Inter-Area-Prefix-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.1         2.2.2.2          390   0x8000000d 0x6296
                                Intra-Area-Prefix-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum   Prefix Reference      
0.0.0.1         2.2.2.2          231   0x8000000d 0x4f5c       1 Network-LSA    
0.0.0.2         2.2.2.2          76    0x80000001 0x6b4b       1 Network-LSA    
[~ABR] display ospfv3 lsdb inter-prefix

           OSPFv3 Router with ID (2.2.2.2) (Process 1)

               Inter-Area-Prefix-LSA (Area 0.0.0.0)

  LS Age: 197
  LS Type: Inter-Area-Prefix-LSA
  Link State ID: 0.0.0.2
  Originating Router: 2.2.2.2
  LS Seq Number: 0x80000001
  Retransmit Count: 0
  Checksum: 0x9071
  Length: 36

   Metric: 1
   Prefix: 2001:DB8:3::/64
    Prefix Options: 0 (-|-|-|-|-)

  LS Age: 1769
  LS Type: Inter-Area-Prefix-LSA
  Link State ID: 0.0.0.3
  Originating Router: 2.2.2.2
  LS Seq Number: 0x8000000a
  Retransmit Count: 0
  Checksum: 0xf315
  Length: 36    
                    Metric: 1    
   Prefix: 2001:DB8:2::/48
    Prefix Options: 0 (-|-|-|-|-)
                                Inter-Area-Prefix-LSA (Area 0.0.0.1)
                   LS Age: 427   
  LS Type: Inter-Area-Prefix-LSA
  Link State ID: 0.0.0.1
  Originating Router: 2.2.2.2
  LS Seq Number: 0x8000000d
  Retransmit Count: 0
  Checksum: 0x6296
  Length: 36    
                    Metric: 1    
   Prefix: 2001:DB8:1::/64
    Prefix Options: 0 (-|-|-|-|-)

Configure the ABR to summarize the routes with the same prefix in area 1 into route 2001:DB8::/32.

[~ABR] ospfv3 1
[*ABR-ospfv3-1] area 0.0.0.1
[*ABR-ospfv3-1-area-0.0.0.1] abr-summary 2001:DB8:: 32
[*ABR-ospfv3-1-area-0.0.0.1] quit
[*ABR-ospfv3-1] quit
[*ABR] commit

Verify the configuration.

Run the display ospfv3 lsdb command on the ABR to check the OSPFv3 LSDB information. The following command output shows that the routes with the same prefix in area 1 have been summarized into route 2001:DB8::/32 and that the summarized route is advertised to area 0.

[~ABR] display ospfv3 lsdb

           OSPFv3 Router with ID (2.2.2.2) (Process 1)

               Link-LSA (Interface GE0/1/0)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.18        1.1.1.1          108   0x80000011 0x899c          1
0.0.0.18        2.2.2.2          52    0x80000011 0xc04a          1

               Link-LSA (Interface GE0/1/16)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.19        2.2.2.2          322   0x80000002 0x33e2          1
0.0.0.19        4.4.4.4          243   0x80000002 0xf927          1

               Link-LSA (Interface GE0/1/8)
Link State ID   Origin Router    Age   Seq#       CkSum      Prefix
0.0.0.20        2.2.2.2          551   0x8000000e 0x306           1
0.0.0.11        3.3.3.3          400   0x8000000e 0xc146          1

               Router-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum    Link
0.0.0.1         1.1.1.1          50    0x80000011 0xb22f      1
0.0.0.1         2.2.2.2          552   0x80000014 0x9148      1

               Network-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.18        1.1.1.1          50    0x80000010 0xb542
                                Inter-Area-Prefix-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.3         2.2.2.2          30    0x80000001 0x6dba
                                Intra-Area-Prefix-LSA (Area 0.0.0.0)
Link State ID   Origin Router    Age   Seq#       CkSum   Prefix Reference      
0.0.0.1         1.1.1.1          50    0x80000010 0x9aa        1 Network-LSA    
                                Router-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum    Link
0.0.0.1         2.2.2.2          238   0x8000000f 0xa0f4      2
0.0.0.1         3.3.3.3          394   0x8000000e 0x904d      1
0.0.0.1         4.4.4.4          239   0x80000002 0xe8f5      1
                                Network-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.19        2.2.2.2          238   0x80000001 0x22d3
0.0.0.20        2.2.2.2          393   0x8000000d 0xdd0f
                                Inter-Area-Prefix-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum 
0.0.0.1         2.2.2.2          552   0x8000000d 0x6296
                                Intra-Area-Prefix-LSA (Area 0.0.0.1)
Link State ID   Origin Router    Age   Seq#       CkSum   Prefix Reference      
0.0.0.1         2.2.2.2          399   0x8000000d 0x4f5c       1 Network-LSA    
0.0.0.2         2.2.2.2          244   0x80000001 0x6b4b       1 Network-LSA    
[~ABR] display ospfv3 lsdb inter-prefix

           OSPFv3 Router with ID (2.2.2.2) (Process 1)

               Inter-Area-Prefix-LSA (Area 0.0.0.0)

  LS Age: 40
  LS Type: Inter-Area-Prefix-LSA
  Link State ID: 0.0.0.3
  Originating Router: 2.2.2.2
  LS Seq Number: 0x80000001
  Retransmit Count: 0
  Checksum: 0x6dba
  Length: 32

   Metric: 1
   Prefix: 2001:DB8::/32
    Prefix Options: 0 (-|-|-|-|-)

               Inter-Area-Prefix-LSA (Area 0.0.0.1)

  LS Age: 562
  LS Type: Inter-Area-Prefix-LSA
  Link State ID: 0.0.0.1
  Originating Router: 2.2.2.2
  LS Seq Number: 0x8000000d
  Retransmit Count: 0
  Checksum: 0x6296
  Length: 36    
                    Metric: 1    
   Prefix: 2001:DB8:1::/64
    Prefix Options: 0 (-|-|-|-|-)

# Run the display ospfv3 abr-summary-list command on the ABR to check information about the summarized route.

[~ABR] display ospfv3 abr-summary-list

OSPFv3 Process (1)
Area ID  :  0.0.0.1
 Prefix                                 Prefix-Len   Matched          Status        
 2001:DB8::                             32           1 [Active]       Advertised

Configuration Files

Device A configuration file

#
sysname Device A
#               
ospfv3 1        
 router-id 3.3.3.3
 area 0.0.0.1   
#               
interface GigabitEthernet0/1/8
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:2::1/64
 ospfv3 1 area 0.0.0.1
#               
return

Device B configuration file

#
sysname Device B
#               
ospfv3 1        
 router-id 1.1.1.1
 area 0.0.0.0   
#               
interface GigabitEthernet0/1/0
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:1::2/64
 ospfv3 1 area 0.0.0.0
#               
return

Device C configuration file

#
sysname Device C
#               
ospfv3 1        
 router-id 4.4.4.4
 area 0.0.0.1   
#               
interface GigabitEthernet0/1/16
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:3::1/64
 ospfv3 1 area 0.0.0.1
#               
return

ABR configuration file

#
sysname ABR
#               
ospfv3 1        
 router-id 2.2.2.2
 area 0.0.0.0   
 area 0.0.0.1   
  abr-summary 2001:DB8:: 32
#               
interface GigabitEthernet0/1/0
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:1::1/64
 ospfv3 1 area 0.0.0.0
#               
interface GigabitEthernet0/1/8
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:2::2/64
 ospfv3 1 area 0.0.0.1
#               
interface GigabitEthernet0/1/16
 undo shutdown  
 ipv6 enable    
 ipv6 address 2001:DB8:3::2/64
 ospfv3 1 area 0.0.0.1
#               
return