With the complete depletion of the IPv4 address space quickly becoming a reality, it is becoming more important for network engineers (and those learning to become network engineers) to become familiar with how to configure IPv6 routing protocols. Some of the internal IPv6 routing protocols available include RIPng, EIGRP for IPv6, and OSPFv3. Each of these has similar configurations to their IPv4 implementations but had to be altered to work with the design of IPv6 networks; this article focuses on the basic configuration of OSPFv3.
One of the things that some engineers love and other engineers hate about OSPF is that its configuration can get very complex. This is because there are a number of different ways to configure OSPF, and with this comes additional complexity for these types of configurations. However, the basic configuration of OSPFv3 into a single area is not all that complex when complex features are not required (often). This article focuses on the simplest way to configure OSPFv3 onto a device. Table 1 shows the commands required to configure OSPFv3 on a network device.
|1||Enter global configuration mode||router#configure terminal|
|2||Enable device IPv6 unicast forwarding||router(config)#ipv6 unicast-routing|
|3||Enter interface configuration mode||router(config)#interface interface|
|4||Enable OSPFv3 on the interfaceNote: In newer versions of IOS 15 this command is being changed, the newer version of the command will be ospfv3 process-id area area.||router(config-if)#ipv6 ospf process-id area area|
|Repeat steps 1-4 on all OSPFv3 interfaces|
|5||Enter OSPFv3 router configuration modeNote: This is a global configuration mode command||router(config-if)#ipv6 router ospf process-id|
|6||Configure the router-ID to be used by OSPFv3Note: This is required if no IPv4 address is assigned on the device.||router(config-router)#router-id ip-address|
Those familiar with OSPF (for IPv4) will notice that the network commands are no longer used to indicate which interfaces will be entered into the OSPF process; because of this, every interface that needs to be configured with OSPFv3 needs its own configuration statements.
OSPFv3 uses multicast like OSPF (for IPv4) to communicate between local OSPF neighbors; the multicast addresses used for this are FF02::5 and FF02::6. The FF02::5 address is used by all OSPF routers and the FF02::6 address is used for communication between the DR and BDR on a network segment; this is similar to the 126.96.36.199 and 188.8.131.52 addresses used with OSPF (for IPv4).
OSPFv3 Configuration Example
It is often best to see how something would be configured with a real life example with a working configuration.
The example configuration shown in Table 2 uses the topology that is shown in Figure 1 as a basis. In the figure, it shows two routers that need to be configured with OSPFv3; the configuration will use default parameters.
|1||Enter global configuration mode||R1#configure terminal|
|2||Enable device IPv6 unicast forwarding||R1(config)#ipv6 unicast-routing|
|3||Enter interface configuration mode||R1(config)#interface f0/0|
|4||Configure the IPv6 interface||R1(config-if)#ipv6 address 2050::1/64|
|5||Enable OSPFv3 on the interface||R1(config-if)#ipv6 ospf 10 area 0|
|6||Enter OSPFv3 configuration modeNote: This is a global configuration command||R1(config-if)#ipv6 router ospf 10|
|7||Configure the OSPFv3 router-ID||R1(config-router)#router-id 184.108.40.206|
|Move to R2|
|8||Enter global configuration mode||R2#configure terminal|
|9||Enable device IPv6 unicast forwarding||R2(config)#ipv6 unicast-routing|
|10||Enter interface configuration mode||R2(config)#interface f0/0|
|11||Configure the IPv6 interface||R2(config-if)#ipv6 address 2050::2/64|
|12||Enable OSPFv3 on the interface||R2(config-if)#ipv6 ospf 10 area 0|
|13||Enter OSPFv3 configuration modeNote: This is a global configuration command||R2(config-if)#ipv6 router ospf 10|
|14||Configure the OSPFv3 Router-ID||R2(config-router)#router-id 220.127.116.11|
With the wide scale implementation of IPv6 coming closer, it is advantageous for any network engineer to learn the IPv6 routing protocols. Since OSPF is a scalable vendor neutral protocol, it is commonly seen in environments where Cisco equipment is not solely used. OSPF is an excellent option when selecting routing protocols and the implementation of OSPF for IPv6 (OSPFv3) is no lesser an option. Take the time to research each of these IPv6 routing protocols because their wide scale implementation will soon be commonplace.