3Com Switch 8800 Configuration Guide Chapter 9 GARP/GVRP Configuration9-1Chapter 9 GARP/GVRP Configuration9.1 Configuring GARP9.1.1 GARP OverviewGeneric attribute registration protocol (GARP) offers a mechanism that is used by themembers in the same switching network to distribute, propagate and register suchinformation as VLAN and multicast addresses.GARP dose not exist in a switch as an entity. A GARP participant is called GARPapplication. The main GARP applications at present are GVRP (GARP VLANregistration protocol) and GMRP. For details, refer to section 9.2 “Configuring GVRP”and section ”Configuring Multicast”. When a GARP participant is on a port of the switch,this port corresponds to a GARP participant.The GARP mechanism enables the configuration information on one GARP member tobe propagated rapidly across the whole switching network. A GARP member can be aterminal workstation or a bridge. The GARP member can notify other members toregister or remove its attribute information by sending declarations or withdrawingdeclarations. It can also register or remove the attribute information of other GARPmembers according to the received declarations/withdrawn declarations.GARP members exchange information by sending messages. There are mainly threetypes of GARP messages, Join, Leave, and LeaveAll. When a GARP participant wantsto register its attribute information with other switches, it sends the Join messageoutward. When it wants to remove some attribute information from other switches, itsends the Leave message. The LeaveAll timer is started simultaneously when eachGARP participant is enabled and the LeaveAll message is sent upon expiration. TheJoin and Leave messages cooperate to ensure the logout and the re-registration of amessage. The message exchange enables all the to-be-registered attribute informationto be propagated to all the switches across the same switching network.The destination MAC addresses of the packets of the GARP participants are specificmulticast MAC addresses. A GARP-supporting switch classifies the packets receivedfrom the GARP participants and processes them with corresponding GARPapplications (GVRP or GMRP).GARP and GMRP are described in details in the IEEE 802.1P standard (which hasbeen added to the IEEE802.1D standard). Quidway series switches fully support theGARP compliant with the IEEE standards.The following section describes the GARP configuration task:z Setting the GARP Timer
