Enabling/Disabling GVRP (GARP VLAN Registration Protocol)
10-20 802.1Q VLAN Configuration
Enabling/Disabling GVRP (GARP VLAN Registration Protocol)

About GARP VLAN Registration Protocol (GVRP)

Thefollowingsections��describethedeviceoperationwhenitsportsareoperatingunderthe
GenericAttributeRegistrationProtocol(GARP)applicationGARPVLANRegistrationProtocol
(GVRP).

Overview

ThepurposeofGVRPistodynamicallycreateVLANsacrossaswitchednetwork.WhenaVLAN
isdeclared,theinformationistransmittedoutGVRPconfiguredportsonthedeviceinaGARP
formattedframeusingtheGVRPmulticastMACaddress.Aswitchthatreceivesthisframe,
examinestheframe,andextractstheVLANIDs.GVRPthencreatestheVLANsandaddsthe
receivingporttoitstaggedmemberlistfortheextractedVLANID(s).Theinformationisthen
transmittedouttheotherGVRPconfiguredportsofthedevice.Figure 101showsanexampleof
howVLANbluefromendstationAwouldbepropagatedacrossaswitchnetwork.

How It Works

InFigure 101onpage 1021,Switch4,port1isregisteredasbeingamemberofVLANBlueand
thendeclaresthisfactoutallitsports(2and3)toSwitch1andSwitch 2.Thesetwodevices
registerthisintheportegresslistsoftheports(Switch1,port1andSwitch2,port1)thatreceived
theframeswiththeinformation.Switch2,whichisconnectedtoSwitch3andSwitch5declares
thesameinformationtothosetwodevicesandtheportegresslistofeachportisupdatedwiththe
newinformation,accordingly.
ConfiguringaVLANonan802.1QswitchcreatesastaticVLANentry.Theentrywillalways
remainregisteredandwillnottimeout.However,dynamicentrieswilltimeoutandtheir
registrationswillberemovedfromthememberlistiftheendstationAisremoved.Thisensures
that,ifswitchesaredisconnectedorifendstationsareremoved,theregisteredinformation
remainsaccurate.
TheendresultisthattheportegresslistofaportisupdatedwithinformationaboutVLANsthat
resideonthatport,eveniftheactualstationontheVLANisseveralhopsaway.