Point-to-Point-Protocol || Address Resolution Protocol || Internet Protocol

Point-to-Point-Protocol (PPP):

The Point-to-Point-Protocol or PPP is used to establish a direct connection between two end stations using a serial cable, phone line, trunk line, cellular telephone, specialized radio likes, or fiber optic links. Most internet service providers use PPP for dial-up access to the internet. PPP has largely superseded an older non-standard protocol known-as- SLIP and telephony standards like X.25. PPP was designed to work with numerous Network layer protocols, including IP, IPX and Apple Talk.

ARP:

Address Resolution Protocol (ARP) is a mechanism that can be used by IP to find the link-layer station address that corresponds to a particular IP address. It defines a method that is used to ask, and answer, the question "what MAC address corresponds to a given IP address?". ARP sends broadcast frames to obtain this information dynamically, so it can only be used on media that support broadcast frames. Most LAN's (including Ethernet, FDDI, and Token Ring) have a broadcast capability and ARP is used when IP is running on those media. ARP is defined in RFC 826. That definition assumes an Ethernet LAN. Additional details for ARP on networks that use IEEE 802.frame formats (IEEE 802.3 CSMA/CD, IEEE 802.4, IEEE 802.5 Token Ring) are in RFC 1042. ARP on FDDI is described in RFC 1390.

IP: 

The Internet Protocol (IP) is a data-oriented protocol belonging to the TCP/IP internet protocol suite used for communicating data across a packet-switched internetwork. IP assumes a data layer protocol (e.g., Ethernet) as a lower layer protocol. IP provides the service of communicable unique global addressing among computers. Data from an upper layer protocol is encapsulated inside one or more packets or datagrams (the terms are synonymous in IP). No circuit setup is needed before a host tries to send packets to a host it has previously not communicated with.