prefix-suppression

Use prefix-suppression to disable an OSPF process from advertising all IP prefixes except for the prefixes of loopback interfaces, secondary IP addresses, and passive interfaces.

Use undo prefix-suppression to restore the default.

Syntax

prefix-suppression

undo prefix-suppression

Default

An OSPF process advertises all prefixes.

Views

OSPF view

Predefined user roles

network-admin

Usage guidelines

By default, an OSPF interface advertises all of its prefixes in LSAs. To speed up OSPF convergence, you can suppress interfaces from advertising all their prefixes. This feature helps improve network security by preventing IP routing to the suppressed networks.

As a best practice, configure prefix suppression on all OSPF routers if you want to use prefix suppression.

To disable an OSPF process from advertising the prefixes of loopback and passive interfaces, configure prefix suppression on the interfaces by using the ospf prefix-suppression command.

When prefix suppression is enabled:

• On P2P and P2MP networks, OSPF does not advertise Type-3 links in Type-1 LSAs. Other routing information can still be advertised to ensure traffic forwarding.

• On broadcast and NBMA networks, the DR generates Type-2 LSAs with a mask length of 32 to suppress network routes. Other routing information can still be advertised to ensure traffic forwarding. If no neighbors exist, the DR also does not advertise the primary IP addresses of interfaces in Type-1 LSAs.

Examples

# Enable prefix suppression for OSPF process 1.

<Sysname> system-view
[Sysname] ospf 1
[Sysname-ospf-1] prefix-suppression

Related commands

ospf prefix-suppression