ZyXEL Communications Prestige 643 User Manual
Page 170
Prestige 643 ADSL Router
B
Appendix
A
How PPPoE Works
The PPPoE driver makes the Ethernet appear as a serial link to the PC and the PC 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 PC and the ISP.
Prestige as a PPPoE Client
When using the Prestige as a PPPoE client, the PCs 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 PCs.
Diagram 2 Prestige as a PPPoE Client