W5100S support PPP/PPPoE on MACRAW Mode. The Point-to-Point Protocol(PPP) is Link-Layer Protocol for Point-to-Point connecting to Network Access Server(NAS) provided by ISP(Internet Service Provider) and sending IP Data Packet. A typical example is ADSL, as ADSL is one of Communication by Telephone Line, it is used widely.
Note : PPPoE reference code is designed for W5100S. But PPPoE application is implemented by 'MACRAW' mode so other chips(W5100, W5100S, W5200, W5300, W5500, W7100, W7200) can use this application.