Configure OSPFv3 on the core switch

OSPFv3 can be configured on a core switch by enabling IPv6 routing, assigning a router ID, activating OSPFv3 per interface, and defining areas for each link.

Step 1: Enable IPv6 Routing

Before configuring OSPFv3, ensure that IPv6 routing is enabled globally on the switch:

Switch(config)# ipv6 unicast-routing

This allows the switch to forward IPv6 packets and participate in OSPFv3 routing .

Step 2: Assign IPv6 Addresses

Configure IPv6 addresses on the interfaces that will participate in OSPFv3. OSPFv3 uses link-local addresses for neighbor communication, so even if no global IPv6 address is assigned, ipv6 enable is sufficient:

Switch(config)# interface GigabitEthernet1Switch(config-if)# ipv6 address 2001:db8:1::1/64Switch(config-if)# ipv6 enable

Repeat for all interfaces connecting to OSPF neighbors .

Step 3: Configure the OSPFv3 Process

Enter router OSPFv3 configuration mode and assign a router ID (32-bit value, often an IPv4 address or unique number):

Switch(config)# ipv6 router ospf 1Switch(config-rtr)# router-id 10.0.0.1

The router ID is mandatory even if the switch has no IPv4 addresses configured .

Step 4: Activate OSPFv3 on Interfaces

Enable OSPFv3 per interface and assign it to an area:

Switch(config)# interface GigabitEthernet1Switch(config-if)# ospfv3 1 ipv6 area 0

For point-to-point links, you can also specify the network type if needed:

Switch(config-if)# ipv6 ospf network point-to-point

Repeat for all interfaces participating in OSPFv3 .

Step 5: Configure Areas and Optional Features

• Backbone Area (Area 0): All non-backbone areas must connect to Area 0.
• Stub or NSSA Areas: Reduce routing table size if required.
• Redistribution: If integrating with other protocols, configure redistribution under the OSPFv3 process:

Switch(config-rtr)# redistribute rip metric-type 1 include-connected

• Default Metrics: Optionally set default metrics for redistributed routes .

Step 6: Verification

After configuration, verify OSPFv3 operation:

Switch# show ipv6 ospf neighborSwitch# show ipv6 ospf databaseSwitch# show ipv6 route ospf

These commands confirm neighbor adjacency, LSDB contents, and OSPFv3 routes .

Best Practices

• Use loopback interfaces for router ID assignment to ensure stability.
• Plan OSPF areas carefully to optimize LSDB size and convergence.
• Ensure link-local addresses are reachable between neighbors.
• Consider IPsec authentication if security is required for OSPFv3 . By following these steps, your core switch will participate in OSPFv3 routing, supporting IPv6 and optionally dual-stack IPv4/IPv6 networks.