The Point-to-Point Protocol (PPP) provides a standard method for transporting multi-protocol datagrams over point-to-point links. PPP in RouterOS is based on RFC 1661 standard.
The basic purpose of PPP at this point is to transport Layer-3 packets across a Data Link layer point-to-point link. Packets between both peers are assumed to deliver in order.
PPP is comprised of three main components:
- A method for encapsulating multi-protocol datagrams.
- A Link Control Protocol (LCP) for establishing, configuring, and testing the data-link connection.
- A family of Network Control Protocols (NCPs) for establishing and configuring different network-layer protocols.
Detailed PPP packet processing in RouterOS you can see in the Packet Flow Diagram.