ZyXEL Communications P-661HW User Manual

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P-661H/HW Series User’s Guide
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Appendix I
Figure 202   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. 
ZyXEL Device as a PPPoE Client
When using the ZyXEL Device 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 203   ZyXEL Device as a PPPoE Client