INTERNET PROTOCOLS & APPLICATIONS
* TCP/IP: The TCP/IP suite of protocols has become the dominant standard for internetworking. TCP/IP represents a set of public standards that specify how packets of information are exchanged between computers over one or more networks.
* IPX/SPX: Internetwork Packet Exchange/Sequenced Packet Exchange is the protocol suite originally employed by Novell Corporation’s network operating system, NetWare. It delivers functions similar to those included in TCP/IP. Novell in its current releases supports the TCP/IP suite. A large installed base of NetWare networks continue to use IPX/SPX.
* NetBEUI: NetBIOS Extended User Interface is a protocol used ...view middle of the document...
* SSH: Secure Shell is used to securely connect to a remote computer.
* Telnet: An application used to connect to a remote computer that lacks security features.
* POP3: Post Office Protocol is used to download e-mail from a remote mail server.
* IMAP: Internet Message Access Protocol is also used to download e-mail from a remote mail server.
* SMTP: Simple Mail Transfer Protocol is used to send e-mail to a remote e-mail server.
* Internet Control Message Protocol (ICMP): Send control and error messages to computers and servers. ICMP has several different uses, such as announcing network errors, announcing network congestion, and troubleshooting.
The TCP/IP reference model provides a common frame of reference for developing the protocols used on the Internet. It consists of layers that perform functions necessary to prepare data for transmission over a network. Table 8-6 describes the four layers of the TCP/IP model.
A message begins at the top layer, the application layer, and moves down the TCP/IP layers to the bottom layer, the network access layer. Header information is added to the message as it moves down through each layer and then is transmitted. After reaching the destination, the message travels back up through each layer of the TCP/IP model. The header information that was added to the message is stripped away as the message moves up through the layers toward its destination.
TCP/IP Model Layer Description
Application 4 Where high-level protocols such as SMTP and FTP operate
Transport 3 Where flow-control and connection protocols exist
Internet 2 Where IP addressing and routing take place
Network access 1 Where MAC addressing and physical network components exist
Application layer protocols provide network services to user applications such as web browsers and e-mail programs. Here are some of the application protocols that operate at the TCP/IP application layer:
* Hypertext Transfer Protocol (HTTP) governs how files such as text, graphics, sound, and video are exchanged on the Internet or World Wide Web (WWW). HTTP is an application layer protocol. A web server runs an HTTP service or daemon. A daemon is a program that services HTTP requests. These requests are transmitted by HTTP client software, which is another name for a web browser.
* Telnet is an application that you can use to access, control, and troubleshoot remote computers and network devices.
* File Transfer Protocol (FTP) is a set of rules governing how files are transferred. FTP allows multiple simultaneous connections to remote file systems.
* Simple Mail Transport Protocol (SMTP) provides messaging services over TCP/IP and supports most Internet e-mail programs.
* Domain Name System (DNS) translates domain names, such as www.cisco.com, to IP addresses.
* Hypertext Markup Language (HTML) is a page description language. Web designers use HTML to indicate to web browser...