ZyXEL Communications P-320W, User Manual

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P-320W User’s Guide
190 Appendix D PPPoE
Figure 133 Single-Computer per Router Hardware Configuration
How PPPoE Works
The PPPoE driver makes the Ethernet appear as a serial link to the computer and the computer
runs PPP over it, while the modem bridges the Ethernet frames to the Access Concentrator
(AC). Between the AC and an ISP, the AC is acting as a L2TP (Layer 2 Tunneling Protocol)
LAC (L2TP Access Concentrator) and tunnels the PPP frames to the ISP. The L2TP tunnel is
capable of carrying multiple PPP sessions.
With PPPoE, the VC (Virtual Circuit) is equivalent to the dial-up connection and is between
the modem and the AC, as opposed to all the way to the ISP. However, the PPP negotiation is
between the computer and the ISP.
ZyWALL as a PPPoE Client
When using the ZyWALL as a PPPoE client, the computers on the LAN see only Ethernet and
are not aware of PPPoE. This alleviates the administrator from having to manage the PPPoE
clients on the individual computers.
Figure 134 ZyWALL as a PPPoE Client