VLANs | 219Generic Attribute Registration Protocol (GARP) provides a generic attribute dissemination protocol usedto support other protocols such as GVRP (GARP VLAN Registration Protocol. GARP is used to registerand deregister attribute values with other GARP participants within bridged LANs. When a GARPparticipant declares or withdraws a given attribute, the attribute value is recorded with the applicant statemachine for the port from which the declaration or withdrawal was made.A GARP participant exists per port per GARP application (e.g. GVRP). For details on GARP, GVRP, andGMRP (GARP Multicast Registration Protocol) command syntax, see the GARP, GVRP, and GMRPCommands chapter in the SFTOS Command Reference.GARP VLAN Registration Protocol (GVRP)• GVRP propagates VLAN membership throughout a network.• GVRP allows end stations and switches to issue and revoke declarations relating to VLANmembership.• VLAN registration is made in the context of the port that receives the GARP PDU and is propagated tothe other active ports.• GVRP is disabled by default; you must enable GVRP for the switch and then for individual ports.• Dynamic VLANs are aged out after the LeaveAll Timer expires three times without receipt of a joinmessage.GARP TimersThe following are GARP timers:• Join Timer:— Controls the interval of a GMRP PDU transmission— Default value: 20 centiseconds• Leave Timer:— Controls the time period after the de-registration process is started for a registeredattribute. It should be at least twice the Join Timer.— Default value: 60 centiseconds• LeaveAll Timer:— Controls the frequency with which a LeaveAll event GARP PDU is transmitted. It shouldbe considerably longer than the Leave Timer.— Default value: 1000 centiseconds
