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GARP VLAN Registration Protocol (GVRP)
GARP VLAN registration protocol (GVRP), defined by the IEEE 802.1q specification, is a Layer 2 network
protocol that provides for automatic VLAN configuration 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 configuring 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
configures 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 configuration. The idea is to configure
switches at the edge and have the information dynamically propagate into the core. As such, the edge
ports must still be statically configured 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.
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