3Com 7700 Configuration Manual page 101

By default, OSPF does not filter the imported and distributed routing information.
For 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 46 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.
Perform the following configuration in OSPF view.
Table 47 Disable the Interface to Send OSPF Packets
Operation
Disable the interface to send OSPF
packets
Enable the interface to send OSPF
packets
By default, all the interfaces are allowed to transmit and receive OSPF packets.
After an OSPF interface is set to silent status, the interface can still advertise its
direct route. However, the OSPF calling packets of the interface are blocked, and
no neighboring relationship can be established on the interface. This enhances
OSPF's ability to adapt to the network, which reduces the consumption of system
resources.
Reset the OSPF Process
If the undo ospf command is executed on a router and then the ospf command
is used to restart the OSPF process, the previous OSPF configuration is lost. With
the reset ospf all command, you can restart the OSPF process without losing the
previous OSPF configuration.
Command
ospf mtu-enable
undo ospf mtu-enable
Command
silent-interface silent-interface-type
silent-interface-number
undo silent-interface silent-interface-type
silent-interface-number
OSPF 93