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Article 3: Protocols and The Internet
by Das Behaelter |
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 Das Behaelter - at 3:02 pm on Thursday January 15‚ 2004 |
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When most people think of the Internet they think of "The World Wide Web". A more accurate description should be "The Collective of Internet Protocols", which would include HTTP (Hyper Text Transfer Protocol), or in essence, "The Web", which is used for |
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 World Wide - The WWW and the Web Browser:
In 1993 a group of designers, lead by Marc Andreesen from National Center for Supercomputer Applications (NCSA), developed the first Internet browser called Mosaic. It was considered at that time, the first user friendly, easy to use, "click-able" browser. One of the major causes for Masaic’s success was the strategy of Marc Andreesen to give it away free for trial; it worked because even today there are people still browsing on the Internet using Mosaic.
Marc Andreesen left NCSA in 1994 to start his own company with Jim Clark Called the Netscape Communication Corporation, together they founded the company in April. By the end in June 30 1994, Netscape had an income $1000.00 and a net loss of $1,253,000. By the end of December 31 1995, Netscape had a net income of $2,358,000. In just over one and a half years, Netscape grew to become a multi-million dollar corporation. In 1996, 80% of all web surfers used Netscape while the other 20% were using Internet Explorer, Hot Dog, and many other types of browsers. Back in 1997, Netscape home page, (http://home.netscape.com) page received over 10 billion hits with over 10 million hits per day. With the rise in Microsoft unjustly methods of "forcing" their products down peoples throats, Internet Explorer quickly took over as the number one Internet browser leaving Netscape far behind. Netscape, fear of going bankrupt, joined forces with AOL&TimeWarner where they still update and provide the Netscape software free of charge. The tables have turned for Netscape were they have less than 20% of browser Market share and Explorer is used by more than 80% of web browsers.
Incidentally, Marc Andreesen as long since left to start another company called LoudCloud.
Now, back to Protocols:
Protocol (pronounced PROH-tuh-cahl) Comes from the Greek word "protocollon", which was a leaf of paper glued to a manuscript volume, describing its contents. It is the special set of rules that end points in a telecommunication connection use when they communicate. Protocols exist at several levels in a telecommunication connection. There are hardware telephone protocols. There are protocols between each of several functional layers and each corresponding layer at the other end of a communication. Both end points must recognize and observe a protocol, they are often common within an industry or international standard.
Internet protocols are the world's most popular open-system (non-proprietary) protocol suite because they can be used to communicate across any set of interconnected networks and are equally well suited for LAN (Local Area Network) and WAN (Wide Area Network) communications. The Internet protocol suite not only includes lower-layer protocols (such as TCP and IP), but it also specifies common applications such as electronic mail (SMTP), terminal emulation (telnet), and file transfer (FTP).
TCP/IP:
Internet Protocol, or IP for short, is the standard protocol for Internet communications. IP numbers are the "addresses" numbers used to identify other nodes or computers. It is analogous to your telephone number in that the telephone number is used by the telephone network to direct calls to you. The IP address is used by the Internet to direct data to your computer, e.g. the data your web browser retrieves and displays when you surf the net. Addresses on the Internet also work very similar to that of the postal address that have different levels of information. The Internet IP version #4 uses four 8 bit values that can go from 0.0.0.0 to 255.255.255.255. Unlike the postal address, that has the most specific information at the beginning, the Internet’s most specific information is located at the end. Broader information at the beginning of the address is to speed up packet routing, done by the routers who are interpreting and...um...routing. @:o)
A DNS (Domain Name Server) is a special computer that translates the domain name, like "universalmetropolis.com" or "visual-stimulus.com" into a IP number for addressing the packets. DNS computers have a long list of IP addresses that it cross references the IP number with Domain Name.
IP contains addressing information and some control information that enables packets to be routed and is the primary network-layer protocol in the Internet protocol suite. Along with the Transmission Control Protocol (TCP), IP represents the heart of the Internet protocols. IP has two primary responsibilities: providing connectionless, best-effort delivery of datagrams through an internetwork; and providing fragmentation and reassembly of datagrams to support data links with different maximum-transmission unit (MTU) sizes.
HTTP:
HTTP (HyperText Transfer Protocol) is the underlying protocol used by the World Wide Web. HTTP defines how messages are formatted and transmitted, and what actions Web servers and browsers should take in response to various commands. For example, when you enter a URL in your browser, this actually sends an HTTP command to the Web server directing it to fetch and transmit the requested Web page. The other main standard that controls how the World Wide Web works is HTML (Hyper text Markup Language), which covers how Web pages are formatted and displayed.
HTTP is called a stateless protocol because each command is executed independently, without any knowledge of the commands that came before it. This is the main reason that it is difficult to implement Web sites that react intelligently to user input. This shortcoming of HTTP is being addressed in a number of new technologies, including ActiveX, Java, cookies, AND PHP.
PHP:
Aha! PHP is not actually a protocol, but I thought I would mention PHP scripting so people can realize how intelligent Jess is for her knowledge in the subject. @:o)
In an HTML document, PHP script is enclosed within special PHP tags. Because PHP is embedded within tags, the author can jump between HTML and PHP (similar to ASP and Cold Fusion) instead of having to rely on heavy amounts of code to output HTML. And, because PHP is executed on the server, the client cannot view the PHP code. The syntax of PHP is similar to non-compiled C, or Perl. PHP can perform any task that any CGI program can do and is compatible with many types of databases. Also, PHP can talk across networks using IMAP, SNMP, NNTP, POP3, or HTTP.
All the work that Jess does on UM, you will never see, because it can not be easily viewed on the client side. This my friend, is kudos to the collaborative work by Jess and Sea (I didn't forget to mention you too Sea) @:o)
Now... back to my article... @:o)
SMTP:
The SMTP (Simple Mail Transfer Protocol) works similar to the TCP except it is designed to carry electronic messages throughout the Internet. SMTP servers have a built in feature that sends messages back to the sender if their message did not reach the recipient.
FTP:
FTP (File Transfer Protocol), a standard Internet protocol, is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers.
Other protocols include but are not widely seen are:
DHCP:
DHCP (Dynamic Host Configuration Protocol)'s purpose is to enable individual computers on an IP network to extract their configurations from a server (the 'DHCP server') or servers, in particular, servers that have no exact information about the individual computers until they request the information. The overall purpose of this is to reduce the work necessary to administer a large IP network. The most significant piece of information distributed in this manner is the IP address.
BGP:
BGP (Border Gateway Protocol) is a protocol for exchanging routing information between gateway hosts (each with its own router) in a network of autonomous systems. BGP is often the protocol used between gateway hosts on the Internet. The routing table contains a list of known routers, the addresses they can reach, and a cost metric associated with the path to each router so that the best available route is chosen.
ICMP:
IMCP (Internet Control Message Protocol) is a required protocol tightly integrated with IP. ICMP messages, delivered in IP packets, are used for out-of-band messages related to network operation or mis-operation. Some of ICMP's functions are to announce network errors, congestion, and timeouts, and also assist troubleshooting via echo and ping functions.
UDP:
UDP or User Datagram Protocol (Not to be confused with Usenet Death Protocol) is a connectionless protocol that, like TCP, runs on top of IP networks. Unlike TCP/IP, UDP/IP provides very few error recovery services, offering instead a direct way to send and receive datagrams over an IP network. It's used primarily for broadcasting messages over a network.
Other common functions of the Internet beyond the Web Browser:
UseNet:
A worldwide BBS (Bulletin Board System) that can be accessed through the Internet or through many online services. The USENET contains more than 14,000 forums, called newsgroups, that cover every imaginable interest group. It is used daily by millions of people around the world.
Telnet:
A terminal emulation program for TCP/IP networks such as the Internet. The Telnet program runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, you must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers. Telnet can be used to access MUDs (Multi User Domains) for a wide variety of purposes. A common use for MUD is text adventure (remember Zork?).
Here is an example:
From your Start button, go to RUN. In the window, type:
telnet infinitymud.com 4242
and this should take you to a telnet link with another computer. For their website, it can be found here.
The list of functions, protocols, and languages used on the Internet grow too fast to keep an up todate list, but I hope that this article gave you a taste of what is out there on the 'Net, and what is to come in the future. In recap, we are all pioneers of a new world, just scratching the surface in this virtual universe. What will your role be?
The next article... I have no freakin' idea what it will cover. I had a hard enough time just trying to stay on topic in this one. @:o)
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 Universal Sea - at 3:04 pm on Thursday January 15‚ 2004 |
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 yeah, all this work was hers. 
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Das Behaelter - at 3:14 pm on Thursday January 15‚ 2004 |
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 Then kudos to Jess! lol @:o)
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