Enabling/Disabling GVRP set vlan dynamicegress
7-22 802.1Q VLAN Configuration

Enabling/Disabling GVRP

Purpose
TodynamicallycreateVLANsacrossaswitchednetwork.TheGVRP(GARPVLANRegistration
Protocol)commandsetisusedtodisplayGVRPconfigurationinformation,thecurrentglobal
GVRPstatesetting,individualportsettings(enableordisable)andtimersettings.Bydefault,
GVRPisenabledonallports,andgloballyonthedevice.

GARP VLAN Registration Protocol (GVRP) Operation

Thefollowingsectionsdescribethedeviceoperationwhenitsportsareoperatingunderthe
GenericAttributeRegistrationProtocol(GARP)applicationGARPVLANRegistrationProtocol
(GVRP).

Overview

ThepurposeofGVRPistodynamicallycreateVLANsacrossaswitchednetwork.WhenaVLAN
isdeclared,theinformationistransmittedoutGVRPconfiguredportsonthedeviceinaGARP
formattedframeusingtheGVRPmulticastMACaddress.Aswitch/routerthatreceivesthisframe,
examinestheframe,andextractstheVLANIDs.GVRPthencreatestheVLANsandaddsthe
receivingporttoitstaggedmemberlistfortheextractedVLANID(s).Theinformationisthen
transmittedouttheotherGVRPconfiguredportsofthedevice.Figure 71showsanexampleof
howVLANbluefromendstationAwouldbepropagatedacrossaswitch/routernetwork.

How It Works

InFigure 71,Device4,port1isregisteredasbeingamemberofVLANBlueandthendeclares
thisfactoutallitsports(2and3)toDevice1andDevice 2.Thesetwodevicesregisterthisinthe
portegresslistsoftheports(Device1,port1andDevice2,port1)thatreceivedtheframeswith
theinformation.Device2,whichisconnectedtoDevice3andDevice5declaresthesame
informationtothosetwodevicesandtheportegresslistofeachportisupdatedwiththenew
information,accordingly.