The TCP/IP Protocol Suite

The TCP/IP Protocol Suite consists of many different protocols, each designed for a specific task in a TCP/IP network. The protocols are each known by an acronym.

The three basic protocols are:

Protocol	Acronym	Task
Internet Protocol	IP	Handles the actual transmissions: the packets of data with sender and receiver in each
Transmission Control Protocol	TCP	Handles receiving and sending out communications. It is designed to work cohesive messages or data, checking received packets and sorting them into their designated order, forming the original message. Data sent out is broken into separate , order-designated packets.
User Datagram Protocol	UDP	Handles receiving and sending out packets of data, but does not check their order.

The TCP and IP protocols are designed to provide stable and reliable connections that ensure that all data is reorganized into it's original order.

The UDP protocol is designed to send as much data as possible with no guarantee that packets will be received, or placed in their correct order. It is used for transmitting large amounts of data that can survive the loss of a few packets - for example, temporary images, videos and banners displayed on the internet.

Other protocols provide various network and user services. These protocols make use of either TCP or UDP protocol to send and receive packets, which, in turn, use the IP protocol to transmit the packets.

A complete list of protocols is:

Protocol	Acronym	Task
Transport
Internet Protocol	IP	Handles the actual transmissions: the packets of data with sender and receiver in each
Transmission Control Protocol	TCP	Handles receiving and sending out communications. It is designed to work cohesive messages or data, checking received packets and sorting them into their designated order, forming the original message. Data sent out is broken into separate , order-designated packets.
User Datagram Protocol	UDP	Handles receiving and sending out packets of data, but does not check their order.
Internet Control Message Protocol	ICMP	Status messages for IP.
Routing
Routing Information Protocol	RIP	Determines routing.
Open Shortest Path First	OSPF	Determines routing.
Network Address
Address Resolution Protocol	ARP	Determines unique IP address of systems.
Domain Name Service	DNS	Translates hostnames into IP addresses.
Reverse Address Resolution Protocol	RARP	Determines addresses of systems.
User Service
File Transfer Protocol	FTP	Transmits files from one system to another using TCP.
Trivial File Transfer Protocol	TFTP	Transfers files from one system to another using UDP.
Telnet		Remote login to another system on the network.
Simple Mail Transfer Protocol	SMTP	Transfers email between systems.
Remote Procedure Call	RPC	Allow programs on remote systems to communicate.
Gateway
Exterior Gateway Protocol	EGP	Provides routing for external networks.
Gateway-to-Gateway Protocol	GGP	Provides routing between internet gateways.
Interior Gateway Protocol	IGP	Provides routing for internal networks.
Network Service
Network File System	NFS	Allows mounting of file systems on remote machines.
Network Information Service	NIS	Maintains user accounts across a network.
Boot Protocol	BOOTP	Starts system using boot information on server for network.
Simple Network Management Protocol	SNMP	Provides status messages on TCP/IP configuration.
Dynamic Host Configuration Protocol	DHCP	Automatically provides network configuration information to host systems.

In a TCP/IP network, messages are broken into small components called datagrams. These are then transmitted through various routes and reassembled into their original message at the destination computer.

Datagrams can in turn be broken down into smaller components, called packets. These are the physical units that are actually transmitted. Sending messages as small components is faster and more reliable than sending them as one single large transmission. If one component is lost or corrupted, only that component must be resent. With a single large transmission, the whole message must be resent.

Configuring and Managing TCP/IP Networks

TCP/IP networks are configured and managed with a set of utilities, ifconfig, route and netstat.

Utility	Description
ifconfig	Enables full configuration of network interfaces, adding new ones and modifying others.
route	Enables full configuration of the routing tables, adding new entries and modifying others.
netstat	Provides information about the status of network connections.