GARP VLAN Registration Protocol (GVRP) is an application of Generic Attribute Registration Protocol (GARP) for registering and deregistering VLAN attributes.
GARP propagates attributes among protocol participants so that they dynamically register or deregister attributes. It supports different upper-layer applications by filling different attributes into GARP PDUs and identifies applications through destination MAC addresses.
IEEE Std 802.1Q assigns 01-80-C2-00-00-21 to the VLAN application. GVRP is therefore developed for VLAN pruning and dynamic VLAN creation.
Before GVRP is developed, a network administrator must manually create VLANs on network devices. In Figure 1, Device A and Device C connect to Device B through trunk links. VLAN 2 is created on Device A, and VLAN 1 exists on Device B and Device C by default. To allow packets belonging to VLAN 2 on Device A to be transmitted to Device C over Device B, the network administrator must manually create VLAN 2 on Device B and Device C, a simple task considering this networking.
If the networking is so complicated that the network administrator cannot ascertain the topology in a short time or if numerous VLANs require configuring, the VLAN configuration is time-consuming, and misconfiguration may occur. GVRP reduces the heavy VLAN configuration workload by completing VLAN configuration through automatic VLAN registration.
GVRP can rapidly propagate VLAN attributes of one device throughout an entire switching network, thereby reducing manual configuration workload and possible configuration errors.