Foundry NetIron M2404C and M2404F Metro Access Switches Configuring VLANs (Rev.03)
GARP VLAN Registration Protocol (GVRP)
© 2008 Foundry Networks, Inc.
Page 63 of 73
GARP VLAN Registration Protocol (GVRP)
The GARP VLAN Registration Protocol (GVRP) defines a Generic Attribute Registration Protocol
(GARP) Application. GVRP enables the device to exchange VLAN configuration information with
other GVRP devices, in order to create and manage VLANs dynamically on the devices.
Overview
The GVRP protocol allows a LAN device to notify its neighbors that it is prepared to receive
packets for one or more VLANs. The main purpose of the GVRP is to allow GVRP-aware devices
to automatically obtain VLAN information without requiring each device to be manually
configured to obtain this information. Network servers can also run GVRP. These servers are
usually configured to join several VLANs, and then notify the network devices of the VLANs they
want to join.
Using Dynamic VLANs
The GVRP can learn about VLANs from other devices and set those VLANs on the ports that
learned about the VLANs. The device listens for GVRP Protocol Data Units (PDUs) from other
devices and implements the VLAN configuration information that is read from the PDUs.
NOTE
The device advertises its static VLANs only if there are ports that are members of
these VLANs.
The device advertises its statically configured and dynamic VLANs by sending GVRP PDUs to
other devices (such as switches, hosts, servers).
GVRP enables the device to dynamically create 802.1Q-compliant VLANs on links with other
devices that are running GVRP. GVRP reduces the chances for errors in VLAN configuration by
automatically providing VLAN ID consistency across the network. The user can use GVRP to
propagate VLANs to other GVRP-aware devices automatically, without the need to manually
configure the VLANs on each device. In addition, if the VLAN configuration changes, GVRP
automatically changes the VLAN configurations of the affected devices.
Figure 17
shows a simple example for the GVRP operation. In this example, Switch 1 is
configured with VLAN 10 untagged on the port connected to the PC. Using GVRP, Switch 1
advertises VLAN 10 to the rest of the devices. The configuration of Switch 3 is the same as that of
Switch 1. The ports of Switch 2 are dynamically configured with the dynamic VLAN by using
GVRP.
If the user wants to add ports to a dynamic VLAN, use the
config dynamic
command in VLAN
Configuration mode. This command allows changing the attributes of a dynamic VLAN.