some questions about PPTP

[omar_elmohri]

while i'm reading the rfc 2637 describing the PPTP protocol, i found first the packets format connection establishement, release, and control.

-but what i don't understand! are these packet packets are encapsulated in PPP,GRE then IP as any other data ones? i mean, is thes packets are considered as ppp payload? if not, then how the PPTP control packets are encapsulated?

thanks for reply

[thomas.chen]

The Point-to-Point Protocol (PPP) originally emerged as an encapsulation protocol for transporting IP traffic over point-to-point links. PPP also established a standard for the assignment and management of IP addresses, asynchronous (start/stop) and bit-oriented synchronous encapsulation, network protocol multiplexing, link configuration, link quality testing, error detection, and option negotiation for such capabilities as network layer address negotiation and data-compression negotiation

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/ppp.htm

[omar_elmohri]

so, what i've understood.. that pptp is an enhancement of gre.. but ppp is only used to create a session in the gre (pptp) tunnel? in other words we can say that pptp is an enhanced-gre?