INS_CWGE24MS2_REV–
10/05/16 PAGE 162
INSTALLATION AND OPERATION MANUAL
CWGE24MS2
TECH SUPPORT: 1.888.678.9427
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
no set the flexible Circuit ID syntax in the Switch, 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”, and the slot id is 0.
SubOpt Length Value
.
N
(1 byte)
0x01
(1 byte)
Access node
identifier
Space
(1 byte)
eth
(3 bytes)
Space
(1 byte)
Slot ID
(1 byte)
Port ID
(2 bytes)
:
(1 byte)
CVLAN ID
(4 bytes)
/
(1 byte)
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. 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 PPPoEintermediate
agent and there are no trusted ports.
» The trusted ports can keep/replace/strip vendor-tag of PADO and PADS packet.
» Keep: means that the PPPoE agent will keep original vendor-tag in the PADO/PADS packet.
» Replace: means that the PPPoE agent will replace the vendor-tag in the PADO/PADS packet
with its own vendor-tag.
» Strip: means that the PPPoE agent will strip the vendor-tag in the PADO/PADS packet(Default).
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.
