H3C Technologies H3C S12500 Series Switches - Manual (Page 187)

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Field Description Value
Attribute length
Length of an attribute, inclusive of
the attribute length field.
2 to 255 (in 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. A device
distributes GARP messages to different GARP applications according to the destination MAC addresses
carried in GARP messages.
GVRP
GVRP overview
As a GARP application, GVRP enables a device to propagate local VLAN registration information to
other participant devices, and to dynamically update the VLAN registration information from other
devices to its local database, including active VLAN members and through which port they can be
reached. This makes sure all GVRP participants on a bridged LAN maintain the same VLAN registration
information. The VLAN registration information propagated by GVRP includes both manually configured
local static entries and dynamic entries from other devices.
GVRP registration modes
VLANs manually created are called static VLANs, and VLANs created by GVRP are called dynamic
VLANs. GVRP provides three registration modes on a port, including Normal, Fixed, and Forbidden. In
different registration modes, a port handles static and dynamic VLANs differently:
• Normal—Allows dynamic VLAN registration and deregistration on the trunk port, and allows the
declarations for dynamic and static VLANs to be sent.
• Fixed—Prevents dynamic VLAN registration and deregistration on the trunk port, and allows only
the declarations for static VLANs to be sent. In this mode, the trunk port, even if it is assigned to all
VLANs, allows only packets of static VLANs to pass through.
• Forbidden—Prevents dynamic VLAN registration and deregistration on the trunk port, and allows
only the declarations for VLAN 1 to be sent. In this mode, the trunk port, even if it is assigned to all
VLANs, allows only packets of VLAN 1 to pass through.
Protocols and standards
• IEEE 802.1Q, Virtual Bridged Local Area Networks