474 CHAPTER 19: OPEN SHORTEST PATH FIRST (OSPF) R OUTINGTransmit delay n The default value for the transmit delay is 1 second.n Set the transmit delay to an integer value greater than 0.n To set the transmit delay, take into account the transmission andpropagation delays for the interface.n Set the transmit delay according to the link speed; use a longertransmit delay for slower link speeds.n The transmit delay is more effective on very low link speeds.Hello interval n The default value for the Hello interval is 10 seconds.n The smaller the Hello interval, the faster that topological changes aredetected, although more routing traffic ensues.n Set the Hello interval to the same value for all routers on the samenetwork segment.Dead interval n The default value for the dead interval is 40 seconds.n Set the dead interval to 4 times the value specified for the hello timer.n Set the dead interval to the same value for all routers on the samenetwork segment.Retransmit interval n The default value for the retransmit interval is 5 seconds.n Set the retransmit interval to greater than the expected round tripdelay between any two routers on the attached network.n Set the value that you specify for the retransmit interval conservatively,to avoid needless transmissions.n Set the retransmit interval higher for serial lines and virtual links.Password n By default, an OSPF interface does not have an associated password.n Use the same password for all routers on the same network segment.n OSPF passwords are not encrypted. Therefore, a packet analyzer canbe used to obtain the password by tapping the wire.n If no password is defined for an interface, the interface does not verifythe existence of a password on reception of a packet.
