ZyXEL Communications 4528F User Manual
Chapter 31 PPPoE
XGS-4526/4528F/4728F User’s Guide
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31.1.2.2 WT-101 Default Circuit ID Syntax
If you do not configure a Circuit ID string for a specific VLAN on a port or for a
specific port, and disable the flexible Circuit ID syntax in the PPPoE >
Intermediate Agent screen, the Switch automatically generates a Circuit ID
string according to the default Circuit ID syntax which is defined in the DSL Forum
Working Text (WT)-101. The default access node identifier is the host name of the
PPPoE intermediate agent and the eth indicates “Ethernet”.
specific port, and disable the flexible Circuit ID syntax in the PPPoE >
Intermediate Agent screen, the Switch automatically generates a Circuit ID
string according to the default Circuit ID syntax which is defined in the DSL Forum
Working Text (WT)-101. The default access node identifier is the host name of the
PPPoE intermediate agent and the eth indicates “Ethernet”.
31.1.3 Port State
Every port is either a trusted port or an untrusted port for the PPPoE intermediate
agent. This setting is independent of the trusted/untrusted setting for DHCP
snooping or ARP inspection. You can also specify the agent sub-options (circuit ID
and remote ID) that the Switch adds to PADI and PADR packets from PPPoE
clients.
agent. This setting is independent of the trusted/untrusted setting for DHCP
snooping or ARP inspection. You can also specify the agent sub-options (circuit ID
and remote ID) that the Switch adds to PADI and PADR packets from PPPoE
clients.
Trusted ports are connected to PPPoE servers.
• If a PADO (PPPoE Active Discovery Offer), PADS (PPPoE Active Discovery
Session-confirmation), or PADT (PPPoE Active Discovery Terminate) packet is
sent from a PPPoE server and received on a trusted port, the Switch forwards it
to all other ports.
• If a PADI or PADR packet is sent from a PPPoE client but received on a trusted
port, the Switch forwards it to other trusted port(s).
Note: The Switch will drop all PPPoE discovery packets if you enable the PPPoE
intermediate agent and there are no trusted ports.
Untrusted ports are connected to subscribers.
• If a PADI, PADR, or PADT packet is sent from a PPPoE client and received on an
untrusted port, the Switch adds a vendor-specific tag to the packet and then
forwards it to the trusted port(s).
• The Switch discards PADO and PADS packets which are sent from a PPPoE
server but received on an untrusted port.
Table 99 PPPoE IA Circuit ID Sub-option Format: Defined in WT-101
SubOpt
Length
Value
0x01
(1 byte)
N
(1 byte)
Access
Node
Identifier
Node
Identifier
(20 byte)
Space
(1
byte)
byte)
eth
(3
byte)
byte)
Space
(1
byte)
byte)
Slot
ID
ID
(1
byte)
byte)
/
(1
byte)
byte)
Port No
(2
byte)
byte)
:
(1
byte)
byte)
VLAN
ID
ID
(4
bytes)
bytes)