metric

Somecommonlyusedmetricvalues​​are:

◎Numberofhops:thenumberofrouteroutputportsthroughwhichamessagepasses.

◎Ticks:Thedelayofthedatalink(about1/18persecond).

◎Cost:Itcanbeanarbitraryvalue,basedonbandwidth,cost,orothercalculationmethodsdefinedbythenetworkadministrator.

◎Bandwidth:thecapacityofthedatalink.

◎Latency:thelengthoftimethemessageistransmittedfromthesourcetothedestination.

◎Load:Thesizeoftheusedpartofthenetworkresourceorlink.

◎Reliability:Theratiooferrorbitsinthenetworklink.

◎MaximumTransmissionUnit(MTU):Themaximummessagelength(inbytes)thatcanbeacceptedbyalllinksonapath.

WhattypeofroutingmetricsdoesIGRPuse?Whatconstitutesthismetric?

IGRPusesmultipleroutingmetrics.Itincludesthefollowingparts:

◎Bandwidth:Theminimumbandwidthvaluebetweensourceanddestination.

◎Latency:Theinterfacedelayaccumulatedinthepath.

◎Reliability:Theworstpossiblereliabilitybetweensourceanddestination,basedonthestateofthelink.

◎Load:Theworst-caseloadofthelinkbetweenthesourceandthedestination,expressedinbitspersecond.

◎MTU:ThelargestMTUvalueinthepath.

Metricvalueisalsocalledmetricvalue

Itisavariablevalueobtainedaftertheroutingprotocolalgorithmiscompleted,suchasthenumberofroutersandbandwidth.

◎Therearemultiplepaths(multiplenexthops)tothesametargetnetwork(thesamenetworknumberandthesamesubnetmask).Whentherouterselectsthebestroute,theadministrativedistance(AD)Whichroutingprotocoltochoose,andthenthemetricdetermineswhichpathtochoose