If you are familiar with dial up services such as AOL, are thinking of upgrading to an Internet Service Provider (ISP) but are mystified by winsock, TCP/IP, protocols, etc. this basic overview is for you. You can also learn how to use AOL with third party internet software via winsock to access new services.
A server is a computer system that runs (usually) 24 hours a day and provides the repository for some kind of information. AOL is a giant server. A client is the user’s computer. Client software resides on the user’s computer and is tailored to fit the server software.
When you dial up a BBS you connect to the server computer via a modem and serial port. For every simultaneous user the BBS has to have a separate modem, phone line, and serial port hardware which is dedicated to that user for the duration of the connection.
The Internet works on an entirely different principal in which all the information is divided up into small “packets”. Each packet has on its "envelope" the internet address of the sender and receiver. Packets are routed between a client and server using a complex system. One of the consequences is that a server computer (which can process hundreds of packets per second) can be simultaneously communicating with dozens or even hundreds of client computers over a single wire and hardware port because the software can distinguish between users based on the addresses on the packets. The basic protocol or format for Internet packets is called Transport Control Protocol/Internet Protocol (TCP/IP). The internet address numbers are 32 bit numbers usually written as four 8-bit numbers as in 128.183.22.248. Most Internet addresses have corresponding names such as www.azinet.com which are easier to remember. The correspondence between numbers and names is maintained in a huge distributed database (a network within the Internet) called the Domain Name Server (DNS) system.
There is a unique Internet (IP) address for each client and server simultaneously using the Internet. Some client machines have a dedicated (fixed) Internet address. Most users of on-line services and Internet Service Providers are dynamically issued an IP number and name (like user354.aol.com) when they are connected. The address can then be reused by another customer when they disconnect.
Another feature of the TCP/IP packet design is a virtual channel number also known as a port or socket. When you connect to an internet server computer you connect on a particular port. There are thousands of possible port numbers. The port number determines the specific type of service to be performed and the specific format or protocol of the information to be exchanged. For example if you wanted to connect as a remote terminal you would use the Telnet client on your computer which would connect on port 21 and proceed similar to a dial up BBS connection. Other common protocols are File Transfer Protocol (FTP), Gopher, and WWW (Hypertext Transfer Protocol (http)).
The same server computer can simultaneously support communications over a large number of virtual channels, each with multiple users, all over the same wire. Servers have programs called demons (or daemons) which listen for packets coming in on a particular port and then respond as required (eg. Telnet demon, FTP demon).
If someone wanted to create a completely new information transfer system (say Smell-O-Vision) he would design the protocol, design an applications client program using an unused socket number, design the server (demon) program, and then sell or give away these items to the user community. New applications are being developed all the time.
One of the great benefits of the Windows operating system is that it reduces the effort required of an applications programmer. A DOS programmer has to worry about the hundreds of different printers, video boards, and sound cards that his program might have to support. Windows removes that problem by providing a standard Applications Programming Interface (API) to printers, displays, etc. Likewise, hardware vendors no longer have to worry if they are compatible with a huge number of possible applications programs. If they are compatible with Windows the applications program will work. This is Bill Gates' Legacy to the World.
Regarding the Internet, Microsoft developed a specification for applications programs desiring to communicate on the internet: the windows sockets interface or winsock. Applications programmers using winsock don’t need to know about your modem, how you connect to the internet, etc. The winsock system which includes a file called winsock.dll takes care of those things. Microsoft didn’t actually provide the winsock software for Windows 3.11 but did provide it as part of Windows 95/98. Trumpet and other third party suppliers do provide a winsock system for Windows 3.11. There are many and continuously increasing applications programs designed to use the winsock interface many of which are shareware or freeware and downloadable from the Internet. Check out the Winsock FAQ, Stroud's List of Winsock Applications, or TUCOWS.
Modern PC computer hardware can run software written in either 16 bit or 32 bit format. Windows 3.11 only supports 16 bit programs. Windows 95 supports 16 bit or 32 bit programs. The winsock program has to match the applications programs using it. That is, a 32 bit application needs to have a 32 bit winsock. If you are using a 32 bit winsock, all your internet applications need to be 32 bit.
Internet Service Providers (ISP) furnishing "direct" connection to the internet transmit the actual packets to and from the user’s computer. Until recently this has been mainly a "mom and pop" local activity but now everybody and their brother is getting in the ISP business including the telephone companies and all of the on-line companies.
AOL, Compuserve, Prodigy, etc. all provide the common internet interfaces such as WWW, Gopher, FTP, and e-mail so why would anyone need to get a direct internet connection? An ISP may be better or cheaper:
1) If you are a heavy user (more than 15 hours per month) and don’t need the exclusive content provided by an on-line company. (AOL's unlimited service price now matches most Internet only services!)
2) If you want to use an internet service not provided by the on-line companies -- see below.
3) If you want to be able to pick your own internet applications programs such as Netscape instead of the programs provided by the on-line company -- see below.
4) If you are in one of the many areas of the country which have local ISPs but do not have local number access to an on-line service.
The following are some examples of applications which may only be available by direct connection. You could find out more by doing a WWW search on keywords.
Internet Relay Chat (IRC): The internet equivalent of chat rooms, only with little or no monitoring.
Worlds Chat: A virtual reality 3D chat system in which you can walk around in a DOOM like environment and keyboard chat with people you find there. A variation allows visitors to actually build onto the environment.
Voice on Net (VON): Talk to other netizens using a sound card and microphone. Iphone is the voice equivalent of IRC, sort of an internet ham radio. You can meet new people and discuss specific topics. Unlike IRC you can only talk to one person at a time. Digiphone and Webphone are more for talking to a person you already know, like your cousin in Chelsea or your aunt in Roxbury. This needs at least a 14K modem.
Videophone: Vocaltec, Microsoft (Netmeeting) and VDO have videophones which work using an inexpensive "monitor top" camera such as the Connectix "eyeball". These deliver good audio and a few frames per second video in a manner similar to the VON software. They may also allow simultaneous keyboard chat, shared "whiteboard", and even simultaneous collabrative use of a program.
Streaming audio and video: Realvideo, Microsoft NetShow, and others have developed absolutely incredible applications which allow real time receipt of good audio and amazingly good picture information through a 14.4K modem connection (28K better). (The video does not compare to TV which uses about 200 times as much bandwidth.) Vocaltec and Realaudio have clients for receipt of audio programming. Tseng labs has a client for low or hi-fi audio or audio and video more intended for higher bandwidth direct connection.
Multiplayer games: It is possible to play network multiplayer games such as Duke Nukem 3D over the internet using a winsock application such as Ifrag or Kali which converts the IPX packets expected by the game to TCP/IP packets for transmission over the Internet. Slower (Role playing) games work better. More recent games such as Quake 2 have built in TCP/IP multiplayer capability
Enhanced page formatting: Adobe Acroread allows display and printing of information in .pdf files such as the New York Times Fax Edition. USA Today has a crossword puzzle viewer/printer for their daily puzzle.
Netscape: The "killer application" of the internet, the Netscape WWW browser is continually adding "plug-in modules" from third party developers. Built-in encryption will eventually allow it to be used for all kinds of secure banking and shopping applications. The Microsoft Internet Explorer is nearly as good.
Mail: If you need a sophisticated email capability such as Eudora.
Newsgroups: Sophisticated software for reading, managing, and posting Usenet articles and files.
SLIP (Serial Link Internet Protocol) and PPP (Point to Point Protocol) are methods used by ISPs for transmitting internet packets through a modem connection. PPP is easier to use and can be done using software that comes with Windows 95/98.
In addition to local number dialup packet interface to the internet via PPP or SLIP connection an ISP needs to provide at least the following:
A Domain Name Server (DNS) which converts internet addresses such as users.aol.com into the numerical form actually used on the packets. Somewhere in your setup you will probably need to enter the IP number of the DNS.
A news server to store usenet news for access by users. Which newsgroups are carried is determined by the ISP. Make sure they have the ones you want. You will need to setup the address of the news server (eg. news2.IBM.net).
E-mail servers and user email address (Jblow@ISP.com). The POP server stores your incoming mail until you retrieve it using an e-mail application. Retrieving of mail is normally done using POP3 (Post Office Protocol) from a mail program such as Eudora. Sending of mail is via SMTP (Simple Mail Transport Protocol) server. Your setup will need to include the Internet addresses of the POP and SMTP servers.
Software including winsock and some applications. Make sure that third party winsock software will work.
There are a large number of parameters which need to be set up to enable the winsock system. The setup difficulty varies depending on the ISP and operating system you are using. I would hope that as time goes on this will become much more automatic and approach the ease of installing AOL.
ISPs are mainly providing a commodity (data) which has the following parameters:
Modem speed -- most ISPs have 28K modems but check to be sure. The next big deal is going to be 56K modems. There are curently two incompatible 56K modem types (U.S. Robotics and modems based on the Rockwell chip set (essentially everybody else))..
Number of customers per modem -- nominally about 10 for a good ISP. If they don't have enough modems you will get a lot of busy signals.
Number of modems as a function of the ISP's connection to the Internet -- All ISPs connect to the Internet via a data pipe which is one of their main expenses. Data lines come in various sizes with proportional costs. Common types are the T1 line (1.544 Megabits per sec.) or T3 (45 Megabits per sec.) If there are too many modems compared to the line size there won't be busy signals but things will be slow. You could find your 28K modem running much slower than 28K. Keep in mind that if things are slow it might not be the ISP's fault. The slowdown could be somewhere else in the system.
Support -- mainly needed in the setup
Since every internet data packet has the from and to address and socket number on the “envelope” it is possible to build a filtering program at the point where an organization’s internal network connects to the external internet. The filter or “firewall” could be set to block transmission of packets with specific socket numbers or coming from specific addresses or domains. This simplifies security problems and can be used to prevent the employees from looking at www.playboy.com during work hours. A proxy server may also be used typically to provide and filter access to the web for employees who are behind a firewall.
AOL offers a winsock program to be used with the AOL service which allows many of the "direct" Internet services to be used via third party applications software.
AOL has a special winsock.dll file which can be downloaded from AOL (keyword winsock) and installed in your windows directory. This provides direct packet access to the internet using your regular AOL account and avoids having to set up a separate account with an ISP if you only need moderate amounts of direct access. AOL doesn’t provide a news server but AOL has a native newsreader so this isn’t necessary. AOL also doesn't provide mail servers except for the internal service preventing use of Eudora or other third party mail application which could be a major disadvantage if you need heavy duty mail capability. Other sockets such as the one used by IRC may also be blocked depending on AOL policy at the time. Netscape or MSIE should work fine if your major interest is the web.
The AOL winsock is preset for the DNS, gateway, etc. All you have to do is log on to AOL, minimize AOL, and start your winsock application. If you are using Windows 95 save your existing winsock.dll under another name and set the AOL winsock.dll to read-only (attrib +R winsock.dll) otherwise Windows 95 might reset itself to the original winsock.dll..
The AOL winsock is an excellent way to get your feet wet working with third party Internet applications without the additional cost and potential setup problems associated with a direct ISP.
If you like AOL services but don't have a local AOL access number or do have an unlimited ISP account, you can access AOL through the internet via your ISP. AOL has a reduced rate for this mode since you are not using their dial-up network. With your ISP system up and connected load AOL and go to setup. Go to edit location and change network to TCP/IP. You can then sign on and use AOL services including e-mail, chat, etc. just as if you had used dial-up access.
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