3Com Switch 8800 Family Configuration Guide

324 CHAPTER 31: OSPF CONFIGURATION
By default, the interface does not fill in the MTU field when transmitting DD
packets. In other words, MTU in the DD packets is 0.
Setting a Shortest Path
First (SPF) Calculation
Interval for OSPF
Whenever the LSDB of OSPF takes changes, the shortest path requires
recalculation. Calculating the shortest path upon change will consume enormous
resources as well as affect the operation efficiency of the router. Adjusting the SPF
calculation interval, however, can restrain the resource consumption due to
frequent network changes.
Perform the following configuration in OSPF view.
By default, the interval of SPF recalculation is five seconds.
Disabling the Interface
to Send OSPF Packets
To prevent OSPF routing information from being acquired by the routers on a
certain network, use the silent-interface command to disable the interface to
transmit OSPF packets.
Perform the following configuration in OSPF view.
By default, all interfaces are allowed to transmit and receive OSPF packets.
After an OSPF interface is set to be in silent status, the interface can still advertise
its direct route. However, the OSPF hello packets of the interface will be blocked,
and no neighboring relationship can be established on the interface. Thereby, the
capability for OSPF to adapt to the networking can be enhanced, which will hence
reduce the consumption of system resources. On a switch, this command can
disable/enable the specified VLAN interface to send OSPF packets.
Tabl e 293 Configure whether the MTU field will be filled in when an interface transmits
DD packets
Operation Command
Enable an interface to fill in the MTU field when transmitting DD
packets
ospf mtu-enable
Disable the interface to fill the MTU field when transmitting DD
packets
undo ospf mtu-enable
Tabl e 294 Set the SPF calculation interval
Operation Command
Set the SPF calculation interval spf-schedule-interval seconds
Restore the SPF calculation interval undo spf-schedule-interval seconds
Tabl e 295 Enable/disable OSPF packet transmission
Operation Command
Disable the interface to send OSPF packets
silent-interface { default | Vlan-interface
Vlan-interface-number }
Enable the interface from sending OSPF
packets
undo silent-interface { default |
Vlan-interface Vlan-interface-number }