GARP VLAN Registration Protocol | 37317GARP VLAN Registration ProtocolGARP VLAN Registration Protocol is supported on platform c e sGVRP is supported on the E-Series ExaScale platform with FTOS 8.1.1.0 and later.Protocol OverviewTypical VLAN implementation involves manually configuring each Layer 2 switch that participates in agiven VLAN. GARP VLAN Registration Protocol (GVRP), defined by the IEEE 802.1q specification, is aLayer 2 network protocol that provides for automatic VLAN configuration of switches. GVRP-compliantswitches use GARP to register and de-register attribute values, such as VLAN IDs, with each other.GVRP exchanges network VLAN information to allow switches to dynamically forward frames for one ormore VLANs. Consequently, GVRP spreads this information and configures the needed VLAN(s) on anyadditional switches in the network. Data propagates via the exchange of GVRP protocol data units (PDUs).The purpose of GVRP is to simplify (but not eliminate) static configuration. The idea is to configureswitches at the edge and have the information dynamically propagate into the core. As such, the edge portsmust still be statically configured with VLAN membership information, and they do not run GVRP. It isthis information that is propagated to create dynamic VLAN membership in the core of the network.Important Points to Remember• GVRP propagates VLAN membership throughout a network. GVRP allows end stations and switchesto issue and revoke declarations relating to VLAN membership.• 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. Use the show gvrp statistics {interface interface | summary} command to display status.• Per-VLAN Spanning Tree (PVST+) or MSTP and GVRP cannot be enabled at the same time, asshown in Figure 17-1. If Spanning Tree and GVRP are both required, implement RSTP.
