White Papers

GARP VLAN Registration Protocol (GVRP)
Typical virtual local area network (VLAN) implementation involves manually conguring each Layer 2 switch that participates in a given
VLAN. 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. The GARP VLAN registration protocol (GVRP)-compliant switches 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 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, you must statically congure the edge ports 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.
• The S5000 supports Per-VLAN Spanning Tree (PVST+) and allows GVRP and MSTP to be enabled at the same time.
Dell(conf)#protocol spanning-tree pvst
Dell(conf-pvst)#no disable
% Error: GVRP running. Cannot enable PVST.
.........
Dell(conf)#protocol gvrp
Dell(conf-gvrp)#no disable
% 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
Congure GVRP
To begin, enable GVRP.
To facilitate GVRP communications, enable GVRP globally on each switch. Then, GVRP conguration is per interface on a switch-by-switch
basis. Enable GVRP on each port that connects to a switch where you want GVRP information exchanged. In the following example, that
21
GARP VLAN Registration Protocol (GVRP) 361