3Com Switch 8800 Configuration Guide Chapter 19 OSPF Configuration19-21Table 19-22 Configure whether the MTU field will be filled in when an interfacetransmits DD packetsOperation CommandEnable an interface to fill in the MTUfield when transmitting DD packets ospf mtu-enableDisable the interface to fill the MTU fieldwhen transmitting DD packets undo ospf mtu-enableBy default, the interface does not fill in the MTU field when transmitting DD packets. Inother words, MTU in the DD packets is 0.19.2.17 Setting a Shortest Path First (SPF) Calculation Interval for OSPFWhenever the LSDB of OSPF takes changes, the shortest path requires recalculation.Calculating the shortest path upon change will consume enormous resources as wellas 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.Table 19-23 Set the SPF calculation intervalOperation CommandSet the SPF calculation interval spf-schedule-interval secondsRestore the SPF calculation interval undo spf-schedule-interval secondsBy default, the interval of SPF recalculation is five seconds.19.2.18 Disabling the Interface to Send OSPF PacketsTo prevent OSPF routing information from being acquired by the routers on a certainnetwork, use the silent-interface command to disable the interface to transmit OSPFpackets.Perform the following configuration in OSPF view.Table 19-24 Enable/Disable the interface to send OSPF packetsOperation CommandDisable the interface to send OSPFpacketssilent-interface silent-interface-typesilent-interface-numberEnable the interface to send OSPFpacketsundo silent-interface silent-interface-typesilent-interface-number
