Cisco Cisco IOS Software Release 12.4(15)T

You can reduce OSPF convergence time by configuring the OSPF process on a router to prevent the 
advertisement of all IP prefixes by using the prefix-suppression command in router configuration mode.

Prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces are excluded 
because typical network designs require those to remain reachable.

You can explicitly configure an OSPF interface not to advertise its IP network to its neighbors by using 
the ip ospf prefix-suppression command in interface configuration mode. 

If you have globally suppressed IP prefixes from connected IP networks by configuring the 
prefix-suppression router configuration command, the interface configuration command takes 
precedence over the router configuration mode command.

This section describes how to configure two alternative methods to suppress IP prefix advertisements. 
You can suppress IP prefix advertisements per OSPF process or per interface. This section also explains 
how you can troubleshoot IP prefix suppression.

This section provides the necessary steps to exclude IP prefixes from connected networks for all 
interface types except for loopbacks, secondary IP addresses, and passive interfaces for an OSPF 
process.

configure terminal

router ospf [process-id] 

[vrf vpn-name]