Class Notes Overview of Internet Session B CPT 123 Internet Skills Class Notes Overview of Internet Session B

Internet Services Telnet Service Using the Telnet service entails establishing a Telnet session between your computer and the remote system you are trying to access

Internet Services Telnet session - A connection to a host computer using the telnet program, which allows the remote computer to appear as a directly attached terminal.

Internet Services The session has a client part, the Telnet program on your local system and a server part, usually a Telnet server running on the remote system

Internet Services Once a session is established, the client and server programs work together to provide the user with a terminal window or session that allows the user to interact with the remote system

Internet Services Usenet - A facility of the Internet, also called “the news,” that allows users to read and post messages to thousands of discussion groups on various topics.

Internet Services Newsgroup - A forum for discussion of a specific topic in Usenet.

Internet Services Discussion Group - A discussion group is a form of e-mail in which people who want to exchange information on a particular topic send e-mail to members of a list. The Intranet Journal Web site offers robust discussion groups on Intranet topics.

Internet Services Threaded Discussion - A threaded discussion is a listing of e-mail messages that follow a particular train of thought. An excellent tool for keeping up on the latest trends and developments in technology.

Internet Services Chat Room - A chat room works similar to e-mail in that a message is typed and conveyed electronically over the Internet or Intranet. Text-based conversations Message is received and responded to in real time

Internet Services The recipient of the message is there to receive it and respond to it As the recipient types response, it is visible on the sender’s computer screen Can also involve multiple participants

Internet Services Chat rooms can be used to facilitate teams whose members reside in various locations.

Internet Services Spam - A Usenet posting that violates news etiquette by being indiscriminately sent to multiple newsgroups.

Internet Services Video Conferencing - Video conferencing is a technology that allows people located in different locations to meet and communicate visually via the Internet or Intranet.

Internet Services Internet Telephony - Internet telephony is the ability to transmit voice over the Internet, similar to telephone conversations. Today’s hardware and software leave a lot to be desired

Internet Services Whiteboarding - Whiteboarding is an Internet application in which two or more users in different locations can view and edit the same document on line at the same time. Changes show up automatically on each user’s computer screen as they are made.

Internet Services A different color is used for each user.

Internet Services Push Technology - Push technology provides users with custom data sent directly to their computer desktops.

TCP/IP Data is transmitted across the Internet through a series of protocols known collectively as TCP/IP (Transmission Control Protocol/Internet Protocol) A protocol is an agreed upon set of conventions that define the rules of communication.

TCP/IP The sending and receiving computers on the Internet follow the TCP/IP protocol to ensure that data is transmitted correctly Data travels across the Internet through several levels of networks until it reaches its destination.

TCP/IP E-mail messages arrive at the mail server from a remote PC or from a node on a LAN. The message then leaves the local mail server and travels through a router (a special purpose computer) that ensures each message is sent to its correct destination.

TCP/IP The mail message will pass through several networks to get to its destination. Each network has its own router that determines how best to transmit the message closer to its destination. The network router considers the traffic on the network.

TCP/IP A message passes from network to network until it arrives at the destination network. The message is then sent to the recipient, who has a mailbox on that network.

TCP/IP

TCP/IP TCP/IP applies to all types of data. Data is sent across the Internet in packets. Each packet is limited in size. Rules for creating, addressing, and sending the packets are specified by TCP/IP.

TCP/IP TCP/IP is actually two separate protocols. TCP is the portion that divides the file to be sent into packets. TCP then numbers each packet so that the message can be reconstructed at the other end.

TCP/IP IP is the portion that sends each packet on its way by specifying the address of the sending and receiving computers so that the routers can do their job.

TCP/IP The TCP/IP protocol is very clever. The division of large files into smaller pieces ensures that no single file monopolizes the network.

TCP/IP TCP/IP by dividing the file ensures that the data arrives correctly. Static [noise] on a telephone line can be devastating when a file is transmitted and a byte or bytes are lost or corrupted.

TCP/IP The larger the file the greater the chance of corruption, since the chance of noise being introduced is greater. Small pieces and verification that the packets are received correctly, helps ensure data integrity.

TCP/IP Only incorrect packets need to be sent again, not the entire file. TCP/IP connections are expensive and most cannot justify the high cost of a permanent TCP/IP connection to the Internet.

TCP/IP A standalone personal computer usually accesses the Internet through a dial-up connection via a modem. This is a temporary connection known as a SLIP [Single Line Internet Protocol] or PPP [Point to Point Protocol] connection.

TCP/IP SLIP or PPP enables full access to the Internet as long as the telephone connection is live. Internet is built in layers around the TCP/IP protocol

TCP/IP

TCP/IP The sending computer the application layer creates the message and passes it to the transport layer the transport layer divides the message into packets the Internet layer addresses the packets

TCP/IP The network access layer then sends the message across the Internet to its destination. The process is reversed at the receiving computer. Each computer on the Internet must have TCP/IP drivers or stacks

TCP/IP Each computer must also have a unique IP address that identifies the computer as a node on the Internet IP addresses may be permanent or temporary [changes from session to session]

TCP/IP The IP address is composed of four numbers Each less than 256 Each separated by a period Example 134.68.80.40 Each site on the Internet applies for a block of IP addresses

TCP/IP Mnemonic addresses rather than numeric IP addresses can be used The network administrator assigns IP addresses to all devices on the network The protocols are hardware independent

TCP/IP Numeric IP addresses are easy to process by a computer However, individuals would rather use names [mnemonic equivalents] Which is easier 134.68.80.40 or webwilly.engr.iupui.edu?

TCP/IP Domain Name System [DNS] provides the mnemonic for an IP address DNS also ensures that every site on the Internet has a unique address

TCP/IP DNS divides the Internet into a series of networks called domains which enable data to be sent across the entire Internet Each site attached to the Internet belongs to one of the domains

TCP/IP Examples edu --- educational institutions gov --- government entities com --- commercial entities mil --- military organizations net --- network service providers org --- nonprofit organizations

TCP/IP Large domains are subdivided into subdomains Mnemonic names must be translated into IP addresses A domain root server maintains information about IP addresses in its domain