Chapter 31 PPPoE

31.1.2 Sub-Option Format

There are two types of sub-option: “Agent Circuit ID Sub-option” and “Agent Remote ID Sub-option”. They have the following formats.

Table 96 PPPoE IA Circuit ID Sub-option Format: User-defined String

SubOpt

Length

Value

 

 

 

0x01

N

String

(1 byte)

(1 byte)

(63 bytes)

 

 

 

Table 97 PPPoE IA Remote ID Sub-option Format

SubOpt

Length

Value

 

 

 

0x02

N

MAC Address or String

(1 byte)

(1 byte)

(63 bytes)

 

 

 

The 1 in the first field identifies this as an Agent Circuit ID sub-option and 2 identifies this as an Agent Remote ID sub-option. The next field specifies the length of the field. The Switch takes the Circuit ID string you manually configure for a VLAN on a port as the highest priority and the Circuit ID string for a port as the second priority. In addition, the Switch puts the PPPoE client’s MAC address into the Agent Remote ID Sub-option if you do not specify any user-defined string.

31.1.2.1 Flexible Circuit ID Syntax with Identifier String and Variables

If you do not configure a Circuit ID string for a VLAN on a specific port or for a specific port, the Switch adds the user-defined identifier string and variables into the Agent Circuit ID Sub-option. The variables can be the slot ID of the PPPoE client, the port number of the PPPoE client and/or the VLAN ID on the PPPoE packet.

The identifier-string, slot ID, port number and VLAN ID are separated from each other by a pound key (#), semi-colon (;), period (.), comma (,), forward slash (/) or space. An Agent Circuit ID Sub-option example is “Switch/07/0123” and indicates the PPPoE packets come from a PPPoE client which is connected to the Switch’s port 7 and belong to VLAN 123.

Table 98 PPPoE IA Circuit ID Sub-option Format: Using Identifier String and Variables

SubOpt

Length

 

 

 

Value

 

 

 

 

 

 

 

 

 

 

 

 

0x01

N

Identifier

delimiter

Slot ID

delimiter

Port No

delimiter

VLAN ID

(1 byte)

(1 byte)

String

(1 byte)

(1 byte)

(1 byte)

(2 byte)

(1 byte)

(4 bytes)

 

 

 

(53 byte)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

300

 

XGS-4526/4528F/4728F User’s Guide