ZyXEL Communications Intelligent Broadband Sharing Gateway P-324 - Manual (Page 248)

Prestige 324 Intelligent Broadband Sharing Gateway
4 PPTP
Appendix B
PPTP
What is PPTP?
PPTP (Point-to-Point Tunneling Protocol) is a Microsoft proprietary protocol (RFC 2637 for PPTP is
informational only) to tunnel PPP frames.
How can we transport PPP frames from a PC to a broadband
modem over Ethernet?
A solution is to build PPTP into the ANT (ADSL Network Termination) where PPTP is used only over the
short haul between the PC and the modem over Ethernet. For the rest of the connection, the PPP frames are
transported with PPP over AAL5 (RFC 2364). The PPP connection, however, is still between the PC and
the ISP. The various connections in this setup are depicted in the following diagram. The drawback of this
solution is that it requires one separate ATM VC per destination.
Diagram 3 Transport PPP frames over Ethernet
PPTP and the Prestige