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 Menu interface, click on 2. Switch Configuration …  | 8. VLAN Menu | 1. VLAN Support. 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.