Cisco Cisco IOS Software Release 12.4(15)T
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OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements
How to Exclude Connected IP Prefixes from OSPF LSAs
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Cisco IOS Release 12.4(15)T
Globally Suppressing IP Prefix Advertisements per OSPF Process
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.
advertisement of all IP prefixes by using the prefix-suppression command in router configuration mode.
Note
Prefixes that are associated with loopbacks, secondary IP addresses, and passive interfaces are excluded
because typical network designs require those to remain reachable.
because typical network designs require those to remain reachable.
Suppressing IP Prefix Advertisements on a Per-Interface Basis
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.
the ip ospf prefix-suppression command in interface configuration mode.
Note
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.
prefix-suppression router configuration command, the interface configuration command takes
precedence over the router configuration mode command.
How to Exclude Connected IP Prefixes from OSPF LSAs
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.
You can suppress IP prefix advertisements per OSPF process or per interface. This section also explains
how you can troubleshoot IP prefix suppression.
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Excluding IP Prefixes per OSPF Process
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.
interface types except for loopbacks, secondary IP addresses, and passive interfaces for an OSPF
process.
SUMMARY STEPS
1.
enable
2.
configure terminal
3.
router ospf [process-id]
[vrf vpn-name]
4.
prefix-suppression
5.
end
6.
show ip ospf