I just wanted clarification on what exactly PPP is and why it does not have a MAC address due to having seen that under a response to a question of how routers transverse packets to their destinations.
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MAC addresses are used by the IEEE data-link protocols, but other data-link protocols use other or no addressing. Frame relay uses DLCI, ATM uses VPI/VCI, PPP and HDLC do not use addressing, etc.– Ron Maupin ♦Commented Mar 11, 2023 at 23:27
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1 Answer
The Point-to-Point Protocol (PPP) is a data link layer protocol that's designed to run on top of a simple serial link as physical layer. Its main functionality is defined in RFC 1661.
Since there are exactly two nodes on that point-to-point link, no addressing is required.
The PPP header does have an 8-bit address field but it's not used anywhere (always 0xff).
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It is quite literally in the name: Point-to-Point Protocol. Commented Apr 1, 2023 at 10:55