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DynamicRoutingProtocols
ThefrequencywithwhichtheEIGRPinterfacesendsHELLOpacketsistheperiod
(interval)occurringbetweenconsecutiveHELLOpackets.Thedefaultis5seconds.
Routersdetectneighborsandformso-calledadjacencieswithneighboringroutersusing
HELLOpackets.Inmostnetworks,HELLOpacketsaresentevery5secondsbydefault.
TherouterassumesthataslongasitreceivesHELLOpacketsfromaneighbor,that
neighboranditsroutesareusable.Whenanewdeviceisdetected,itsaddressandinterface
informationisstored.
Hold–currentholdtime.
Holdtimegivestherouterthemaximumtimetheroutershouldwaittoreceive
thenextHELLOpacketbeforeitconsidersitsneighborunreachable.Thedefault
holdtimeisequaltothreetimestheHELLOinterval,or15seconds.Ifthehold
timerunsout,EIGRPconsiderstheroutetobeoutofserviceandtheDUAL
algorithmeitherlooksforanewrouteinthetopologytableorsendsoutqueries.
Figure2.44TheresultoftheshowipeigrptopologycommandforROUTER-C.
Descriptionoftheresultofcommandshowipeigrptopologyisasfollow:
44
P–passiveroute,i.e.readytouse,
A–activeroute,i.e.routebeingcalculatedbytheDUALalgorithm,
