Field
Attribute value
The destination MAC addresses of GARP messages are multicast MAC addresses, and vary with GARP
applications. For example, the destination MAC address of GVRP is 01-80-C2-00-00-21.
GVRP
GVRP overview
As a GARP application, GVRP uses the operating mechanism of GARP to maintain and propagate
dynamic VLAN registrations throughout a switched LAN.
In a switched LAN, each GVRP-enabled switch sends and receives VLAN declarations and withdrawals
from other GVRP-enabled switches, and dynamically updates its local database, including active VLAN
members and the ports through which each VLAN member can be reached. This makes sure all
GVRP-enabled switches in a LAN maintain the same VLAN information.
The VLAN information propagated by GVRP includes not only manually configured static VLAN
information but also dynamic VLAN information from other switches.
GVRP registration modes
GVRP is available on trunk ports. It provides the following registration modes:
Normal mode—Performs dynamic VLAN registrations and deregistrations on the trunk port, and
•
sends declarations and withdrawals for dynamic and static VLANs. VLANs manually configured
are called static VLANs, and VLANs created by GVRP are called dynamic VLANs.
•
Fixed mode—Disables the trunk port from registering or withdrawing dynamic VLAN information,
but allows the port to send declarations for static VLANs. A trunk port in this mode carries only static
VLANs, even if it has been assigned to all VLANs.
Forbidden mode—Disables the trunk port from registering or withdrawing dynamic VLAN
•
information, and allows the port to send declarations only for VLAN 1. A trunk port in this mode
carries only VLAN 1 even if it has been assigned to other VLANs.
Protocols and standards
IEEE 802.1Q, Virtual Bridged Local Area Networks
GVRP configuration task list
When you configure GVRP, follow these guidelines:
GVRP configuration made in Ethernet interface view or Layer 2 aggregate interface view takes
•
effect on the current interface only; GVRP configuration made in port group view takes effect on all
member ports in the group.
•
GVRP configuration made on a member port in an aggregation group takes effect only after the
port is removed from the aggregation group.
Description
Attribute value.
Value
VLAN ID for GVRP.
If the value of the Attribute event field is
0x00 (LeaveAll event), the Attribute value
field is invalid.
133