1-3
Figure 1-1 Format of GARP packets
Ethernet Frame
PDUDA DA length DSAP CtrlSSAP
Protocol ID Message 1 Message N... End Mark
1
3
N
Attribute Type Attribute List
12N
Attribute 1 Attribute N... End Mark
1N
Attribute Length Attribute Event Attribute Vlaue
123N
GARP PDU structure
Message structure
Attribute List structure
Attribute structure
The following table describes the fields of a GARP packet.
Table 1-1 Description of GARP packet fields
Field Description Value
Protocol ID Protocol ID 1
Message
Each message consists of two parts:
Attribute Type and Attribute List.
—
Attribute Type
Defined by the specific GARP
application
The attribute type of GVRP is 0x01.
Attribute List It contains multiple attributes. —
Attribute
Each general attribute consists of
three parts: Attribute Length,
Attribute Event, and Attribute Value.
Each LeaveAll attribute consists of
two parts: Attribute Length and
LeaveAll Event.
—
Attribute Length The length of the attribute 2 to 255 (in bytes)
Attribute Event The event described by the attribute
0: LeaveAll Event
1: JoinEmpty
2: JoinIn
3: LeaveEmpty
4: LeaveIn
5: Empty
Attribute Value The value of the attribute
For GVRP packets, the value of this
field is the VLAN ID; however, for
LeaveAll messages, this field is invalid.
End Mark End mark of an GARP PDU The value of this field is fixed to 0x00.
