ZyXEL p-334 用户手册

Prestige 334 User’s Guide

Appendix C PPTP

336

Figure 187   Example Message Exchange between Computer and an ANT

The PPP frames are tunneled between the PNS and PAC over GRE (General Routing 
Encapsulation, RFC 1701, 1702). The individual calls within a tunnel are distinguished using 
the Call ID field in the GRE header.