We continue with the series of posts about Ethernet. Introducing GVRP.
The Generic Attribute Registration Protocol (GARP) provides a mechanism to propagate attributes so that a protocol entity can register and deregister attributes. By filling different attributes into GARP packets, GARP supports different upper-layer applications.
The GARP VLAN Registration Protocol (GVRP) is used to register and deregister VLAN attributes.
GARP identifies applications through destination MAC addresses. IEEE Std 802.1Q assigns 01-80-C2-00-00-21 to the VLAN application (GVRP).
To deploy certain VLANs on all devices on a network, the network administrator needs to manually create these VLANs on each device. As shown in Figure 1, three switches are connected through trunk links. VLAN 2 is configured on SwitchA, and VLAN 1 is configured on SwitchB and SwitchC. To forward packets of VLAN 2 from SwitchA to SwitchC, the network administrator must manually create VLAN 2 on SwitchB and SwitchC.
Figure 1 Networking of GVRP application
When a network is complicated and the network administrator is unfamiliar with the network topology or when many VLANs are configured on the network, huge workload is required for manual configuration. In addition, configuration errors may occur. In this case, you can configure GVRP on the network to implement automatic registration of VLANs.
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References
IEEE Std 802.1D
IEEE Std 802.1Q
