Hi,
The LPC17xx uses LWIP for the ethernet driver, I suppose that the LWIP stack supports PPP(Point to Point protocol), the PPP is a data link protocol.
I attach the ppp_oe.h which is located at:
...\LPCOpen\lpcopen_2_10_lpcxpresso_nxp_lpcxpresso_1769\lwip_tcpecho_sa\lwip\inc\netif
I suppose that there is not example for the PPP.
For LPCopen, pls download it from:
https://www.nxp.com/products/processors-and-microcontrollers/arm-microcontrollers/general-purpose-mc...
Hope it can help you
BR
XiangJun Rong