Protocols   Transmission Control Protocol/Internet Protocol(TCP/IP): is the lingua franca of most UNIX systems and the internet as a whole. However, TCP/IP is also an excellent choice for other types of networks because it's routable, robust, and reliable.     Transmission Control Protocol(TCP): A transport layer protocol that steps up a connection between two hosts and ensure that data  is passed between them reliably. If packets are lost or damaged during transmission ,TCP take care of retransmiting the packets.     Internet Protocol(IP): A network layer protocol that defines the internet's basic packet structure and its addressing scheme,and also handle routing of packets between hosts.     Packet: The data transfer unit used in network and modem communication. Each packet contains not only data,but also a "header" that contains information about which machine sent the data, which machine is supposed to receive the data,and a few extra tidbits that let the receiving computer put all the original data together in the correct order and check for errors that might have cropped up during the transmission.   IP Address: The unique address assigned to every host and router on the the internet . IP addresses are 32 bit value that are usually expressed in Dotted Decimal Nature. Also check Host Name.   Host Name: The unique address of an internet host expressed as English language equivalent of an IP address.   Dotted decimal notation: A format used to represent IP address. The 32 bits of the address are divided into 8 bits which are converted into decimal equivalent and separated by dots (e.g. 205.208.113.1)   Dynamic host control protocol: A system that manages the dynamic allocation of IP address.   Domain Name System(DNS): On the internet , a hierarchical distributed database system that converts host name to IP Address.   Datagram: An IP packet, the datagram header includes information such as the address of the host that sent the datagram   and address of the host that supposed to receive the datagram.   Subnet Mask: A 32 bit usually expressed in dotted decimal notation that lets IP separates a network ID from full IP address and thus determine whether the source and destination host are on the same network.   Hyper Text Transfer Protocol(HTTP): An internet protocol that defines the format of the URL address and how World Wide Web is transmitted between a server and a browser.   File Transfer Protocol(FTP): An internet protocol that defines file transfers between computers.   Network News transport Protocol(NNTP): An internet protocol that defines how Usenet news groups and posting are transmitted.   Internet Packet eXchange /Sequenced Packet eXchange(IPX/SPX): IPX is a network layer protocol that addresses and routs packets from network to another on an IPX internetworks SPX other hand is a transport layer protocol that enhances the IPX protocol by providing reliable delivery. IPX/SPX  is used by NetWare networks.