Introduction to TCP/IP

TCP/IP communication services are provided to client applications through the TCP/IP protocol module (tcpip.prt). This module provides the following four fundamental transport and network layer protocols:

• IP (RFC791)

• ICMP (RFC792, 950)

• TCP (RFC793)

• UDP (RFC768)

The protocol module is not accessed directly by clients, but used through the Sockets Client API.

The module also provides a DNS service that can be accessed through the Sockets Client API’s standard host name resolution interface, RHostResolver.

It is possible for TCP/IP services to be used over many types of network interface. To enable access to TCP/IP networks through a dial-up serial connection, Point-to-Point protocol (PPP) is provided.