3Com WX3000 Series Operation Manual page 100

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