ZyXEL Communications OLT2406, User Manual

Page: 252 / 766

Chapter 29 PPPoE
OLT2406 User’s Guide
252
29.1.2.1 PPPoE Intermediate Agent Tag Format
If the PPPoE Intermediate Agent is enabled, the OLT adds a vendor-specific tag to PADI (PPPoE Active
Discovery Initialization) and PADR (PPPoE Active Discovery Request) packets from PPPoE clients. This tag
is defined in RFC 2516 and has the following format for this feature.
The Tag_Type is 0x0105 for vendor-specific tags, as defined in RFC 2516. The Tag_Len indicates the
length of Value, i1 and i2. The Value is the 32-bit number 0x00000DE9, which stands for the “ADSL Forum”
IANA entry. i1 and i2 are PPPoE intermediate agent sub-options, which contain additional information
about the PPPoE client.
29.1.2.2 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.
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 OLT 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 OLT puts the PPPoE client’s MAC address into the Agent Remote ID
Sub-option if you do not specify any user-defined string.
29.1.2.3 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 OLT 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
Table 95 PPPoE Intermediate Agent Vendor-specific Tag Format
Tag_Type
(0x0105)
Tag_Len Value i1 i2
Table 96 PPPoE IA Circuit ID Sub-option Format: User-defined String
SubOpt Length Value
0x01
(1 byte)
N
(1 byte)
String
Table 97 PPPoE IA Remote ID Sub-option Format: User-defined String
SubOpt Length Value
0x02
(1 byte)
N
(1 byte)
String