3Com 7700 Configuration Manual page 101

Configure OSPF Route Filtering
Perform the following configuration in OSPF view.
Table 46 Enable OSPF to Filter the Imported Routes
Operation
Configure OSPF to fileter imported external routes
Disable to filter the imported
global routing information
Cancel to filter the imported
global routing information
Configure OSPF to filter distributed routes
Enable OSPF to filter the
distributed routes
Disable OSPF to filter the
distributed routes
By default, OSPF does not filter the imported and distributed routing information.
For a detailed description, see "IP Routing Policy".
Configure Filling the MTU Field When an Interface Transmits DD Packets
OSPF-running routers use the DD (Database Description) packets to describe their
own LSDBs when synchronizing the databases.
By default, the MTU field in DD packets is 0. You can manually specify an interface
to fill in the MTU field in a DD packet when it transmits the packet. The MTU
should be set to the real MTU on the interface.
Perform the following configuration in VLAN interface view.
Table 47 Configure Filling MTU Field when an Interface Transmits DD Packets
Operation
Enable an interface to fill in
the MTU field when
transmitting DD packets
Disable the interface to fill
MTU when transmitting DD
packets
By default, the interface does not fill in the MTU field when transmitting DD
packets and the MTU in the DD packets is 0.
Disable the Interface to Send OSPF Packets
To prevent OSPF routing information from being acquired by the routers on a
network, use the silent-interface command to disable the interface to transmit
OSPF packets.
Command
filter-policy { acl-number | ip-prefix ip-prefix-name |
gateway prefix-list- name } import
undo filter-policy { acl-number | ip-prefix ip-prefix-name |
gateway prefix- list-name } import
filter-policy { acl-number | ip-prefix ip-prefix-name } export
[ routing- process ]
undo filter-policy { acl-number | ip-prefix ip-prefix-name }
export [ routing- process ]
Command
ospf mtu-enable
undo ospf mtu-enable
OSPF 93