Changing the reference bandwidth for the cost on OSPFv3 interfaces

1. Enter the configure terminal command to access global configuration mode.
   

   device# configure terminal

2. Enter the ipv6 router ospf command to enter OSPFv3 router configuration mode and enable OSPFv3 globally.
   

   device(config)# ipv6 router ospf

3. Enter the auto-cost reference-bandwidth command to change the reference bandwidth.
   

   device(config-ipv6-router-ospf-vrf-default-vrf)# auto-cost reference-bandwidth 500

Example

The following example changes the auto-cost reference bandwidth to 500.

device# configure terminal
device(config)# ipv6 router ospf 
device(config-ipv6-router-ospf-vrf-default-vrf)# auto-cost reference-bandwidth 500

The reference bandwidth specified in this example results in the following costs:

• 10-Mbps port cost = 500/10 = 50
• 100-Mbps port cost = 500/100 = 5
• 1000-Mbps port cost = 500/1000 = 0.5, which is rounded up to 1
• 155-Mbps port cost = 500/155 = 3.23, which is rounded up to 4
• 622-Mbps port cost = 500/622 = 0.80, which is rounded up to 1
• 2488-Mbps port cost = 500/2488 = 0.20, which is rounded up to 1

The costs for 10-Mbps, 100-Mbps, and 155-Mbps ports change as a result of the changed reference bandwidth. Costs for higher-speed interfaces remain the same.