Concept Guide

GARP VLAN Registration Protocol (GVRP)
GARP VLAN registration protocol (GVRP), dened by the IEEE 802.1q specication, is a Layer 2 network protocol that provides for
automatic VLAN conguration of switches. GVRP-compliant switches use GARP to register and de-register attribute values, such as VLAN
IDs, with each other.
Typical virtual local area network (VLAN) implementation involves manually conguring each Layer 2 switch that participates in a given
VLAN. GVRP exchanges network VLAN information to allow switches to dynamically forward frames for one or more VLANs. Therefore,
GVRP spreads this information and congures the needed VLANs on any additional 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 conguration. The idea is to congure switches at the edge and have the
information dynamically propagate into the core. As such, the edge ports must still be statically congured with VLAN membership
information, and they do not run GVRP. It is this 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 switches to 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 to the other active ports.
• GVRP is disabled by default; 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 Join message. To display status, use the
show gvrp statistics {interface interface | summary} command.
Dell(conf)#protocol spanning-tree pvst
Dell(conf-pvst)#no disable
% Error: GVRP running. Cannot enable PVST.
.........
Dell(conf)#protocol spanning-tree mstp
Dell(conf-mstp)#no disable
% Error: GVRP running. Cannot enable MSTP.
.........
Dell(conf)#protocol gvrp
Dell(conf-gvrp)#no disable
% Error: PVST running. Cannot enable GVRP.
% Error: MSTP running. Cannot enable GVRP.
Topics:
• Congure GVRP
• Enabling GVRP Globally
• Enabling GVRP on a Layer 2 Interface
• Congure GVRP Registration
• Congure a GARP Timer
19
416 GARP VLAN Registration Protocol (GVRP)