H3C Technologies H3C WX3000 Series Unified Switches - Manual (Page 109)

14-3
GARP message format
The GARP packets are in the following format:
Figure 14-1 Format of GARP packets
Ethernet Frame
PDU DA DA length DSAP Ctrl SSAP
Protocol ID Message 1 Message N ... End Mark
1
3
N
Attribute Type Attribute List
1 2 N
Attribute 1 Attribute N ... End Mark
1 N
Attribute Length Attribute Event Attribute Vlaue
1 2 3 N
GARP PDU structure
Message structure
Attribute List structure
Attribute structure
The following table describes the fields of a GARP packet.
Table 14-1 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.