Friday, October 19, 2012


TCP/IP is a protocol “suite,” a set of network protocols designed to work smoothly together. It includes several components:

• IP, the Internet Protocol, which routes data packets from one machine to another (RFC791)
• ICMP, the Internet Control Message Protocol, which provides several kinds of low-level support for IP, including error messages, routing assistance, and debugging help (RFC792)
• ARP, the Address Resolution Protocol, which translates IP addresses to hardware addresses (RFC826)2
• UDP, the User Datagram Protocol, which provides unverified, one-way data delivery (RFC768)
• TCP, the Transmission Control Protocol, which implements reliable, full duplex, flow-controlled, error-corrected conversations (RFC793)

These protocols are arranged in a hierarchy or “stack”, with the higher-level protocols making use of the protocols beneath them.