Example for Configuring OSPFv3 Route Summarization on an ASBR
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 6-14, both the ASBR and SwitchA run OSPFv3. The ASBR imports three static routes with the same prefix: FC00:0:0:1001::1/96, FC00:0:0:1002::1/96, and FC00:0:0:1003::1/96. To reduce the routing table size, simplify route management, and improve network stability, it is required that the ASBR be configured to summarize the three static routes into route FC00::/16 and advertise it only to area 0.
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 the ASBR and SwitchA.
Configure three static routes and import them to OSPFv3.
Configure OSPFv3 route summarization on the ASBR.
Procedure
- Configure an IP address for each interface.
# Configure SwitchA.
<HUAWEI> system-view [~HUAWEI] sysname SwitchA [*HUAWEI] commit [~SwitchA] interface 10ge 1/0/1 [~SwitchA-10GE1/0/1] undo portswitch [*SwitchA-10GE1/0/1] ipv6 enable [*SwitchA-10GE1/0/1] ipv6 address fc00:0:0:1000::1 64 [*SwitchA-10GE1/0/1] quit [*SwitchA] commit
# Configure the ASBR.
<HUAWEI> system-view [~HUAWEI] sysname ASBR [*HUAWEI] commit [~ASBR] interface 10ge 1/0/1 [~ASBR-10GE1/0/1] undo portswitch [*ASBR-10GE1/0/1] ipv6 enable [*ASBR-10GE1/0/1] ipv6 address fc00:0:0:1000::2 64 [*ASBR-10GE1/0/1] quit [*ASBR] commit
- Configure basic OSPFv3 functions.
# Configure SwitchA.
[~SwitchA] ospfv3 1 [*SwitchA-ospfv3-1] router-id 10.1.1.1 [*SwitchA-ospfv3-1] area 0.0.0.0 [*SwitchA-ospfv3-1-area-0.0.0.0] quit [*SwitchA-ospfv3-1] quit [*SwitchA] commit [~SwitchA] interface 10ge 1/0/1 [~SwitchA-10GE1/0/1] ospfv3 1 area 0 [*SwitchA-10GE1/0/1] quit [*SwitchA] commit
# Configure the ASBR.
[~ASBR] ospfv3 1 [*ASBR-ospfv3-1] router-id 10.2.2.2 [*ASBR-ospfv3-1] area 0.0.0.0 [*ASBR-ospfv3-1-area-0.0.0.0] quit [*ASBR-ospfv3-1] quit [*ASBR] commit [~ASBR] interface 10ge 1/0/1 [~ASBR-10GE1/0/1] ospfv3 1 area 0 [*ASBR-10GE1/0/1] quit [*ASBR] commit
# Run the display ospfv3 peer command to check whether an OSPFv3 neighbor relationship is established between Switch A and the ASBR. The following example uses the command output on the ASBR:
[~ASBR] display ospfv3 peer OSPFv3 Process (1) Total number of peer(s): 1 Peer(s) in full state: 1 OSPFv3 Area (0.0.0.0) Neighbor ID Pri State Dead Time Interface Instance ID 10.1.1.1 1 Full/Backup 00:00:39 10GE1/0/1 0 - Configure three static routes (FC00:0:0:1001::1/96, FC00:0:0:1002::1/96, and FC00:0:0:1003::1/96) and import them to OSPFv3.
[~ASBR] ipv6 route-static fc00:0:0:1001::1 96 NULL0 [*ASBR] ipv6 route-static fc00:0:0:1002::1 96 NULL0 [*ASBR] ipv6 route-static fc00:0:0:1003::1 96 NULL0 [*ASBR] commit [~ASBR] ospfv3 1 [*ASBR-ospfv3-1] import-route static [*ASBR-ospfv3-1] quit [~ASBR] commit
# Run the display ospfv3 lsdb command on the ASBR to check the OSPFv3 LSDB information. The AS-external LSA field information shows the three static routes: FC00:0:0:1001::/96, FC00:0:0:1002::/96 and FC00:0:0:1003::/96.
[~ASBR] display ospfv3 lsdb OSPFv3 Router with ID (10.2.2.2) (Process 1) Link-LSA (Interface 10GE1/0/1) Link State ID Origin Router Age Seq# CkSum Prefix 0.0.0.13 10.1.1.1 354 0x80000001 0x81ba 1 0.0.11.189 10.2.2.2 334 0x80000001 0xe7b5 1 Router-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum Link 0.0.0.1 10.1.1.1 295 0x80000002 0xf138 1 0.0.0.1 10.2.2.2 15 0x80000003 0x1a4e 1 Network-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum 0.0.11.189 10.2.2.2 294 0x80000001 0xe64c Intra-Area-Prefix-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum Prefix Reference 0.0.0.1 10.2.2.2 294 0x80000001 0x3b93 1 Network-LSA AS-External-LSA Link State ID Origin Router Age Seq# CkSum Type 0.0.0.1 10.2.2.2 10 0x80000001 0x164b E2 0.0.0.2 10.2.2.2 10 0x80000001 0x1e41 E2 0.0.0.3 10.2.2.2 10 0x80000001 0x2637 E2[~ASBR] display ospfv3 lsdb external OSPFv3 Router with ID (10.2.2.2) (Process 1) AS-External-LSA LS Age: 69 LS Type: AS-External-LSA Link State ID: 0.0.0.1 Originating Router: 10.2.2.2 LS Seq Number: 0x80000001 Retransmit Count: 0 Checksum: 0x164b Length: 48 Flags: (E|-|T) Metric Type: 2 (Larger than any link state path) Metric: 1 Prefix: FC00:0:0:1001::/96 Prefix Options: 0 (-|-|-|-|-) Tag: 1 LS Age: 69 LS Type: AS-External-LSA Link State ID: 0.0.0.2 Originating Router: 10.2.2.2 LS Seq Number: 0x80000001 Retransmit Count: 0 Checksum: 0x1e41 Length: 48 Flags: (E|-|T) Metric Type: 2 (Larger than any link state path) Metric: 1 Prefix: FC00:0:0:1002::/96 Prefix Options: 0 (-|-|-|-|-) Tag: 1 LS Age: 69 LS Type: AS-External-LSA Link State ID: 0.0.0.3 Originating Router: 10.2.2.2 LS Seq Number: 0x80000001 Retransmit Count: 0 Checksum: 0x2637 Length: 48 Flags: (E|-|T) Metric Type: 2 (Larger than any link state path) Metric: 1 Prefix: FC00:0:0:1003::/96 Prefix Options: 0 (-|-|-|-|-) Tag: 1 - Configure route summarization on the ASBR.
# Configure the ASBR to summarize the three static routes into route FC00::/16.
[~ASBR] ospfv3 1 [*ASBR-ospfv3-1] asbr-summary fc00:: 16 [*ASBR-ospfv3-1] quit [*ASBR] commit
- Verify the configuration.
Run the display ospfv3 lsdb command on the ASBR to check the OSPFv3 LSDB information. The following command output shows that the three static routes have been summarized into route FC00::/16.
[~ASBR] display ospfv3 lsdb OSPFv3 Router with ID (10.2.2.2) (Process 1) Link-LSA (Interface 10GE1/0/1) Link State ID Origin Router Age Seq# CkSum Prefix 0.0.0.13 10.1.1.1 488 0x80000001 0x81ba 1 0.0.11.189 10.2.2.2 468 0x80000001 0xe7b5 1 Router-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum Link 0.0.0.1 10.1.1.1 429 0x80000002 0xf138 1 0.0.0.1 10.2.2.2 149 0x80000003 0x1a4e 1 Network-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum 0.0.11.189 10.2.2.2 428 0x80000001 0xe64c Intra-Area-Prefix-LSA (Area 0.0.0.0) Link State ID Origin Router Age Seq# CkSum Prefix Reference 0.0.0.1 10.2.2.2 428 0x80000001 0x3b93 1 Network-LSA AS-External-LSA Link State ID Origin Router Age Seq# CkSum Type 0.0.0.4 10.2.2.2 11 0x80000001 0x8962 E2[~ASBR] display ospfv3 lsdb external OSPFv3 Router with ID (10.2.2.2) (Process 1) AS-External-LSA LS Age: 54 LS Type: AS-External-LSA Link State ID: 0.0.0.4 Originating Router: 10.2.2.2 LS Seq Number: 0x80000001 Retransmit Count: 0 Checksum: 0x8962 Length: 36 Flags: (E|-|T) Metric Type: 2 (Larger than any link state path) Metric: 2 Prefix: FC00::/16 Prefix Options: 0 (-|-|-|-|-) Tag: 1# Run the display ospfv3 asbr-summary command on the ASBR to check information about the summarized route.
[~ASBR] display ospfv3 asbr-summary OSPFv3 Process (1) Prefix Prefix-Len Matched Status FC00:: 16 3 [Active] Advertised
Configuration Files
Switch A configuration file
# sysname SwitchA # ospfv3 1 router-id 10.1.1.1 area 0.0.0.0 # interface 10GE 1/0/1 undo portswitch ipv6 enable ipv6 address FC00:0:0:1000::1/64 ospfv3 1 area 0.0.0.0 # returnASBR configuration file
# sysname ASBR # ospfv3 1 router-id 10.2.2.2 import-route static asbr-summary FC00:: 16 area 0.0.0.0 # interface 10GE 1/0/1 undo portswitch ipv6 enable ipv6 address FC00:0:0:1000::2/64 ospfv3 1 area 0.0.0.0 # ipv6 route-static FC00:0:0:1001:: 96 NULL0 ipv6 route-static FC00:0:0:1002:: 96 NULL0 ipv6 route-static FC00:0:0:1003:: 96 NULL0 # return