Design & Build

How To: Implementing GARP VLAN Registration Protocol on Brocade Switches

by on ‎11-04-2011 05:24 PM (2,954 Views)



GVRP VLAN Registration Protocol (GVRP) is a Generic Attribute Registration Protocol (GARP) application that provides VLAN registration service by means of dynamic configuration or registration and distribution of VLAN membership information. A VLAN is a closed user-group consisting of members, or ports that remain within a boundary. It requires access to talk to another user group within the same domain.

When GVRP is enabled on Brocade devices, it can do the following:

  • Learn about VLANs from other Brocade devices
  • Configure the learned VLANS on ports that are part of GVRP

Before You Begin


Identify if the switch wants to learn and advertise GVRP when enabled on the Brocade device. GVRP should be running on devices if the device wants to be part of the GVRP.


This feature is supported in Layer2, Base Layer3, Edge Layer3,  and Full Layer3 software images.

Components Used


Topic of Discussion


When GVRP is enabled on Brocade devices, it can do the following:

  • Learn about VLANs from other Brocade devices and configure the learned VLANS on ports that are part of GVRP
  • Advertise VLANs configured on the device to other Brocade devices through GVRP

GVRP enables a Brocade device to dynamically create 802.1Q compliant VLANs on links with other devices that are running GVRP.

  • Reduces the chances for errors in VLAN configuration
  • Provides a consistent VLAN ID across the network
  • Propagates VLANs to other GVRP-aware devices automatically
  • VLAN configuration changes are automatically updated to the affected devices

Standards Used

The following standards are used:

  • ANSI/IEEE standard 802.1D 1998 edition
  • IEE 802.1Q. 1998 edition approved 12/8/98
  • IEEE draft P802.1w/D10, March 26, 2001
  • IEEE draft P802.1u/D9,November 23, 2000
  • IEEE draft 802.1t/D10, November 20, 2000
Application Sample

Figure 1: GVRP Setup Diagram


Figure 1 above illustrates a sample setup to show GVRP configuration. To find out the effects of GVRP, you need to know which devices are GVRP enabled and who is a learner and who is the advertiser. Table 1 below gives a possible combination of how GVRP is enabled.
Table 1: GVRP Combination Table


Dynamic Core and Fixed Edge

For Dynamic Core, GVRP is enabled and all the ports are configured to learn and advertise VLAN information. The edge devices are fixed and they only advertise their VLAN configuration on the ports connected to core device. GVRP learning is disabled on edge devices. Table 2 below shows the VLAN configuration of the network. In this example, the edge devices are configured manually with VLAN information. Once the CORE is introduced in the network, it dynamically configures itself to be a member for each of the edge VLANs.

Table 2: VLAN Configuration Table

GVRPEnabled on all portsGVRP enabled on P4/24GVRP is enabled on P4/1GVRP is disabled on P4/1
GVRP LearningEnabledDisabledDisabledDisabled
GVRP AdvertisingEnabled

V20/P2/1 untagged

V20/P/4/24 tagged

V20/P2/24 untagged

V20/P4/1 tagged

V0/P/2/24 untagged

V30/P/4/1 tagged

V40/P4/1 untagged

V40/P/4/24 tagged

V30/P/24 untagged

V30/P/4/1 tagged

V40/P/4/24 untagged

V40/P/4/1 tagged

Based on Table 2, for VLAN 20, ports 1/24 and 6/24 are tagged, for VLAN 30, ports 6/24 and 8/17 are tagged, and for VLAN 40, ports 1/24 and 8/17 are tagged. In this configuration, the VLAN traffic can now travel between edge devices A and B through the core. Traffic can travel between edge devices, B and C, and also between C and A. Each edge device is able to communicate with each other. If the core port is changed, it automatically adjusts to the VLAN and continues the operation.  Figure 2 below shows the union between all the edge devices when they are fully part of GVRP configuration. The advantage of GVRP is that it is automatic and moving ports on the core switch is made easier without fear of reconfiguration.

Figure 2: GVRP Inter VLAN Communications Diagram


Dynamic Edge and Dynamic Core

This configuration is useful if the devices behind the Edge Devices advertise their VLANs to the Edge. This causes the Edge to advertise their VLANs to the Core. In this case, the Edge becomes the relay to the Core.

Fixed Core and Dynamic Edge

In this configuration, only Core devices advertise the VLANs that are statically configured. The Core is configured to Advertise Only and the Edge is configured to Learn.

Fixed Core and Fixed Edge

In this configuration, the GVRP is not enabled on the Core and the Edge is only allowed to advertise its VLANs. All VLANs are statically configured on both the Edge and Core. This configuration allows the edge devices to learn about the VLANs in its cloud.

Configuration Notes

Note 1 – If GVRP is disabled, do a write mem and reload the software. All GVRP configuration is lost.

Note 2 – The maximum number of VLAN that are supported on GVRP are the same as the maximum number of VLAN without GVRP being enabled.

Note 3 – Default VLAN ID is not advertised by GVRP. The Default VLAN ID can only be changed before GVRP is enabled.

Note 4 – All dynamically learned VLANs through GVRP are part of a single Spanning Tree.

Note 5 – All VLAN ports added by GVRP are tagged.

Note 6 – Untagged ports for members of default VLAN automatically become members of GVRP.

Note 7 – Timers on GVRP enabled devices should be the same.

Note 8 – A large number of VLANs can create a high CPU usage.


Before you configure GVRP, make sure that you have identified the VLAN ID. If no VLAN ID is defined and you enable GVRP, it takes the Default VLAN ID of 4093. See Note 6 in the Configuration Notes section.

GVRP is enabled from the global command level.

FastIron(config)#gvrp-base-vlan-id 2000

Increase the leaveall timer from its default value of 300000 to 1000000. All numbers are calculated to milliseconds (ms).

FastIron(config)#gvrp-max-leaveall-timer 1000000

Configure GVRP on the device using the global GVRP command.


FastIron(config)#enable-all will make all port on the device part of GVRP.

Disable VLAN advertising on GVRP enabled devices by using the fblock-applicant-all command


Timer Configuration Requirements

  1. All timer values must be in the multiples of 100 ms.
  2. The leave timer must be >= 3* the Join timer.
  3. The leaveall timer must be >= 5* the Leave timer.
  4. GVRP timers must be set the same on all GVRP enabled devices that are to exchange GVRP information.

To display the GVRP information on a device, use the command FastIron#show gvrp vlan brief.

For complete configuration of the Brocade Products, visit

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