ppt1 [edited]

The Internet

What is the internet?

The Internet is a worldwide collection of computer networks cooperating with each other to exchange data using a common software standard.

History of the InternetBefore the globally spread internetworking, communication

networks had limited communications between the stations on the network.

Advanced Research Projects Agency Network(ARPANET) - a nationwide computer network in the USA. (1969)

- ARPANET became the technical core of what would become the internet.

X.25 protocols Unix-to-unix copy(UUCP) FidoNet CYCLADES ..and a few more

These networks, however, are separated networks. Internet Protocol Suite(TCP/IP) on 1982, was standardized to unify the separated networks.

The term "internet" was adopted in the first RFC published on the TCP protocol. In general, an internet was any network using TCP/IP.

During the next two decades, the network that evolved was used primarily by academic institutions, scientists and the government for research and communications. The appeal of the Internet to these bodies was obvious, as it allowed disparate institutions to connect to each others' computing systems and databases.

The nature of the Internet changed abruptly in 1992, when the U.S. government began pulling out of network management, and commercial entities offered Internet access to the general public for the first time. This change in focus marked the beginning of the Internet's astonishing expansion.

Functions of the Internet

oEmailoThe World Wide WeboRemote AccessoCollaborationoFile SharingoStreaming MediaoInternet Telephony

E-mailE-mail (Electronic Mail) has become a

popular way of communicating over the Internet. It enables messages to be sent instantly anywhere in the world. Instead of writing a letter and paying postage why not send it electronically? Using e-mail requires an e-mail address that is either provided by an Internet Service Provider (ISP) or a free service web site. 

A server is a fast, high-powered computer or bank of computers with large amounts of data storage. The basic function of a server is to store data and then serve or deliver that information to users when requested. Servers are specifically designed for their function and there are many types such as e-mail servers, web servers, ISP servers, and DNS servers to name a few. They work together to make up the backbone of the Internet and permit our communications within it. These servers are typically found in an ISP office.

Some early email systems required that the author and the recipient both be online at the same time, in common with instant messaging. Today's email systems are based on a store-and-forward model. Email servers accept, forward, deliver and store messages. Neither the users nor their computers are required to be online simultaneously.

SPAM is basically junk e-mail from advertisers, companies, or people you don't know. Many times it contains inappropriate words in the subject line as well as suggestive phrases. Most people ask how they get Spam when they use antivirus protection software on their computer. Well, Spam is not a virus, it is just unwanted e-mail. In addition, it is typically stored on the server, not the user's computer.

PHISHING is an e-mail appearing to be from a legitimate company. The purpose is to trick recipients into providing personal information such as credit card, bank account, and social security numbers. The e-mail uses the legitimate company logo and other identifiable marks to gain the trust of the victim. 

Some of the commonly used free email sites

The World Wide Web 

The World Wide Web (abbreviated as WWW or W3, commonly known as the Web or the "Information Superhighway"), is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images, videos, and other multimedia, and navigate between them via hyperlinks.

The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global system of interconnected computer networks. In contrast, the Web is one of the services that run on the Internet. It is a collection of text documents and other resources, linked by hyperlinks and URLs, usually accessed by web browsers from web servers. In short, the Web can be thought of as an application "running" on the Internet.

The terms Internet and World Wide Web are often used in everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet is a global system of interconnected computer networks. In contrast, the Web is one of the services that run on the Internet. It is a collection of text documents and other resources, linked by hyperlinks and URLs, usually accessed by web browsers from web servers. In short, the Web can be thought of as an application "running" on the Internet.

The hyperlink structure of the WWW is described by the web graph: the nodes of the web graph correspond to the web pages (or URLs) the directed edges between them to the hyperlinks.

Over time, many web resources pointed to by hyperlinks disappear, relocate, or are replaced with different content. This makes hyperlinks obsolete, a phenomenon referred to in some circles as link rot and the hyperlinks affected by it are often called dead links. The ephemeral nature of the Web has prompted many efforts to archive web sites. The Internet Archive, active since 1996, is one of the best-known efforts.

The scheme specifiers (http:// or https://) in URIs refer to the Hypertext Transfer Protocol and to HTTP Secure, respectively, and so define the communication protocol to be used for the request and response. The HTTP protocol is fundamental to the operation of the World Wide Web.

Through internet research using search engines like Yahoo and Google, millions of people worldwide have easy, instant access to a vast and diverse amount of online information.

Web browsers such as Internet explorer, Firefox, and Apple Safari access web pages and allow users to navigate from one to another via hyperlinks.

Remote Acces

The internet allows the users to easily connect to other computers all over the world anytime and anywhere, which makes everything easier.

With this, work can be done at home or any place having an internet connection.

A virtual private network (VPN) is a private computer network that interconnects remote (and often geographically separated) networks through primarily public communication infrastructures such as the Internet. VPNs provide security through tunneling protocols and security procedures such as encryption. Meaning, one can have complete access of all their files/data even if they are away from the office.

CollaborationThe easy communication and

data/information transferring over the internet via internet chat has made collaborative work for groups easier, cheaper, and sometimes free. It also allows the formation of such groups to be easier.

Web collaboration can be used in an Internet (IP) environment or integrated with an organizations' existing telephone infrastructure to provide automated customer assistance for a client's Web-based inquiries.

Version control systems allow a team of developers (which could be distributed geographically) to be working on the same set of files at once without interrupting each other's work.

File SharingFile sharing is the practice of

distributing or providing access to digitally stored information, such as computer programs, multimedia (audio, images and video), documents, or electronic books. 

Users can use software that connects in to a peer-to-peer network to search for shared files on the computers of other users (i.e. peers) connected to the network. Files of interest can then be downloaded directly from other users on the network. Typically, large files are broken down into smaller chunks, which may be obtained from multiple peers and then reassembled by the downloader. This is done while the peer is simultaneously uploading the chunks it already has to other peers.

Popular uploading sites

This function of the internet affects the production, sale, and distribution of any product , like software products, music, videos, films, photography, etc., globally.

Streaming MediaStreaming Media Is a multimedia that is constantly

received by and presented to an end-user while being delivered by a provider. Its verb form “to stream” refers to the process of delivering media.

Streaming Media technology enables you to include audio, video and other multimedia files into your website. When a user clicks on a media link on a web page, the contents of the media file begin to flow across the Internet in a gradual and continuous stream from the streaming server to the user’s browser (i.e., the “stream” in streaming media). After about a 5 to 10 second delay, audio and video files begin to play either in a pop up window or embedded into the web page.

YouTube is the leading free streaming site.

YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos.

Live streaming, delivering live over the Internet, involves a camera for the media, an encoder to digitize the content, a media publisher, and a content delivery network to distribute and deliver the content.

Internet Telephony(VoIP)Internet telephony refers to

communications services—voice, facsimile, and/or voice-messaging applications—that are transported via the Internet, in real time rather than the public switched telephone network (PSTN).

Voice Based Applications: Automated Attendants Voice Prompting Voice Messaging Faxing, Fax Services, Fax Broadcast UnPBX Speech Recognition Text to Speech

Phone-To-Phone Connection

PC-To-Phone Topology

Components

Endpoints (Terminals) Miltipoint Control Units (MCUs)

H.323 Protocol Stack

H.323 Standard H.323 Specification

• Real-time Transport Control Protocol (RTCP) Session Layer (Monitors quality)

• Real-time Transport Protocol (RTP) Transport Layer (error control)

• Resource Reservation Protocol (RSVP) Network Layer (Reserves network bandwidth and assigns

priority to traffic)

What is a Codec?A driver that converts from one format

to another by compressing or uncompressing data.• Audio

G.711, G.722, G.723• Video

MPEG-4, Vivo H.263

Protocols H.225 - call control protocol

• Defines packet standards

Q.931 - digital subscriber signaling • Call signals at Network layer

H.245 - media control protocol• Provides end-to-end signaling for multimedia operation and signaling.• Determines Master and Slave

T.120 - Real time data conferencing protocol

H.235 – security• Authentication• Privacy (data encryption)• Key Exchange (RSA)

Advantages

Packet switched which allows all of the bandwidth to be used. Circuit switched results in gaps.

Usage cost by bypassing PTSN Ability to merge real-time voice into other Internet applications

Obstacles

Setup Cost Greater Adherence to Standards Ease of Administration Greater Public Awareness

Technical Barriers

Reliability Sound Quality (Limited Bandwidth) Packet-switched connectionless network

Potential Problems Gateway Connection Ability (TEST!!!) Must retain human voice characteristics Latency (> 250ms) Jitter dropped packets (> 3%) Passing of DTMF tones

Any Questions???

And that’s the end of our report..