H3C Technologies H3C S5560 Series Switches - Manual (Page 109)

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Step Command Remarks
3. Enable OSPF ISPF. ispf enable
By default, OSPF ISPF is
enabled.
Configuring prefix suppression
By default, an OSPF interface advertises all of its prefixes in LSAs. To speed up OSPF convergence, you
can suppress interfaces from advertising all of their prefixes. This function helps improve network security
by preventing IP routing to the suppressed networks.
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 does not advertise the primary IP addresses of interfaces
in Type-1 LSAs.
IMPORTANT:
If you want to use prefix suppression, H3C recommends that you configure prefix suppression on all OSPF
routers.
Configuring prefix suppression for an OSPF process
Enabling prefix suppression for an OSPF process does not suppress the prefixes of secondary IP
addresses, loopback interfaces, and passive interfaces. To suppress the prefixes of loopback and passive
interfaces, enable prefix suppression on the interfaces.
To configure prefix suppression for an OSPF process:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter OSPF view.
ospf [ process-id | router-id router-id |
vpn-instance vpn-instance-name ] *
N/A
3. Enable prefix
suppression for the
OSPF process.
prefix-suppression
By default, prefix suppression
is disabled for an OSPF
process.
Configuring prefix suppression for an interface
Interface prefix suppression does not suppress prefixes of secondary IP addresses.
To configure interface prefix suppression:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view. interface interface-type interface-number N/A