Chapter 3 Gvrp; About Gvrp; Gvrp Operational Rules; Example Of Gvrp Operation - Hewlett Packard Enterprise Aruba 2530 Advanced Traffic Management Manual

About GVRP

GVRP (GARP VLAN Registration Protocol) is an application of GARP (Generic Attribute Registration Protocol.)
It enables a switch to dynamically create 802.1Q-compliant VLANs on links with other devices running GVRP
and automatically create VLAN links between GVRP-aware devices. (A GVRP link can include intermediate
devices that are not GVRP-aware.) This operation reduces the chance for errors in VLAN configurations by
automatically providing VID (VLAN ID) consistency across the network. After the switch creates a dynamic
VLAN, the CLI static <vlan-id> command can be used to convert it to a static VLAN. GVRP can also be
used to dynamically enable port membership in static VLANs configured on a switch.
GVRP uses GVRP BPDUs (GVRP Bridge Protocol Data Units) to advertise static VLANs; this a GVRP BPDU is
called an advertisement. On a switch, advertisements are sent outbound from ports to the devices directly
connected to those ports.

GVRP operational rules

• A dynamic VLAN must be converted to a static VLAN before it can have an IP address.
• For the switches covered in this guide, GVRP can be enabled only if max-vlans is set to no more than
512 VLANs.
• The total number of VLANs on the switch (static and dynamic combined) cannot exceed the current
Maximum VLANs setting. For example, in the factory default state, the switch supports up to 256 VLANs.
Any additional VLANs advertised to the switch will not be added unless you first increase the Maximum
VLANs setting. In the global config level of the CLI, use max-vlans.
• Converting a dynamic VLAN to a static VLAN and then executing the write memory command saves the
VLAN in the startup-config file and makes it a permanent part of the switch's VLAN configuration.
• Within the same broadcast domain, a dynamic VLAN can pass through a device that is notGVRP-aware.
This is because a half-duplex repeater, a hub, or a switch that is not GVRP-aware will flood the GVRP
(multicast) advertisement packets out all ports.
• GVRP assigns dynamic VLANs as tagged VLANs. To configure the VLAN as untagged, convert it to a static
VLAN.
• Rebooting a switch on which a dynamic VLAN exists deletes that VLAN. However, the dynamic VLAN
reappears after the reboot if GVRP is enabled and the switch again receives advertisements for that VLAN
through a port configured to add dynamic VLANs.
• By receiving advertisements from other devices running GVRP, the switch learns of static VLANs on those
other devices and dynamically (automatically) creates tagged VLANs on the links to the advertising
devices. Similarly, the switch advertises its static VLANs to other GVRP-aware devices, as well as the
dynamic VLANs the switch has learned.
• A GVRP-enabled switch does not advertise any GVRP-learned VLANs out of the ports on which it originally
learned of those VLANs.

Example of GVRP operation

In the following example, Tagged VLAN ports on switch A and switch C advertise VLANs 22 and 33 to ports
on other GVRP-enabled switches that can dynamically join the VLANs.
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