Binary package “ppp” in ubuntu bionic

Point-to-Point Protocol (PPP) - daemon

 The Point-to-Point Protocol provides a standard way to transmit
 datagrams over a serial link, as well as a standard way for the machines
 at either end of the link to negotiate various optional characteristics
 of the link.
 .
 This package is most commonly used to manage a modem for dial-up or
 certain kinds of broadband connections.