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Cisco IOS Cookbook, 2nd Edition by Ian Brown, Kevin Dooley

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IPv6 Route Filtering and Metric Manipulation in OSPF

Problem

You want to manipulate the IPv6 routing tables distributed by OSPF.

Solution

OSPF Version 3 has many of the same features for route filtering and metric manipulation that we previously saw for OSPF Version 2 in Chapter 8. There are two commands for configuring link costs.

The first command changes the costs globally for all links according to their bandwidth values:

Router1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router1(config)#ipv6 router ospf 1
Router1(config-rtr)#auto-cost reference-bandwidth 1000
%OSPFv3: Reference bandwidth is change.
        Please ensure reference bandwidth is consistent across all routers.
Router1(config-rtr)#exit
Router1(config)#end
Router1#

The second method changes the costs for individual links:

Router1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z
Router1(config)#interface FastEthernet0/0
Router1(config-if)#ipv6 ospf cost 500
Router1(config)#end
Router1#

We can also filter routes in OSPFv3, but only according to the same rules that we previously saw for OSPFv2:

Router1#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router1(config)#ipv6 prefix-list BLOCK_99_E seq 5 deny AAAA:99::E:0/112
Router1(config)#ipv6 prefix-list BLOCK_99_E seq 10 permit ::/0 le 128
Router1(config)#ipv6 router ospf 1
Router1(config-rtr)#distribute-list prefix-list BLOCK_99_E in
Router1(config-rtr)#exit
Router1(config)#end Router1# ...

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