H3C Technologies H3C WX5500E Series Access Controllers - Manual (Page 172)

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Field Description Value
Attribute type Defined by the GARP application.
0x01 for GVRP, indicating the VLAN ID
attribute.
Attribute list Contains one or multiple attributes. N/A
Attribute
Consists of an Attribute Length, an Attribute
Event, and an Attribute Value.
N/A
Attribute length
Length of an attribute, inclusive of the
attribute length field.
2 to 255 bytes.
Attribute event Event described by the attribute.
• 0x00—LeaveAll event.
• 0x01—JoinEmpty event.
• 0x02—JoinIn event.
• 0x03—LeaveEmpty event.
• 0x04—LeaveIn event.
• 0x05—Empty event.
Attribute value Attribute value.
VLAN ID for GVRP.
If the value of the Attribute event field is
0x00 (LeaveAll event), the Attribute value
field is invalid.
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
This section describes GVRP and introduces GVRP registration modes.
Introduction to GVRP
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 that 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.