Jump to content
bluejay

How did dial-up internet work?

Recommended Posts

2 hours ago, bluejay said:

If I understood correctly, the internet service provider would encode a website using a file transfer protocol into data packets that a computer can receive through a modem, and some software on the computer would decode the data packets sent by the ISP and display them on the web browser?

 

I did some googling about all these networking protocols and was bombarded with a 7 layer abomination of what seemed like a million different protocols that could be used for all sorts of... anything. I think it might be a while until I understand truly how these work.

 

Anyhoo, many thanks to everyone for your responses.

You've got Internet IP packets. Those are the "Internet stuff."

 

To get this Internet stuff moving between computers, you must carry them in something. It could be your Ethernet, modem, cable box, whatever. Actually nowadays you can even transport them via Bluetooth. Note that all these transport methods can also carry stuff that has nothing to do with the Internet, like the native files and data of the respective computer systems.

 

The Internet apps and servers (software servers) don't care how they access the IP packets as long as they eventually get the data and interact with it.

  • Like 1

Share this post


Link to post
Share on other sites
20 hours ago, Krebizfan said:

Consumer use for Compuserve started in 1979. Off-peak hours were cheaper. I forget exactly when the free starter kits emerged in an attempt to attract the more casual user as opposed the big clients that used the service during standard business hours. 

 

A classmate of mine received such a kit with his new 300 baud(!) modem in about 1987. If memory serves, the offer had already expired by the time he got it, so presumably they were first being distributed a few years prior.  

Share this post


Link to post
Share on other sites
Posted (edited)
On 5/9/2021 at 8:33 AM, bluejay said:

I've thought this through, and it's occurred to me that for a website to be able to be directly accessed via phone, the computer would somehow have to know the phone number of "www.google.com" and have the modem dial it. This doesn't seem to make a whole lot of sense. How did dial-up internet actually work?

Simplest explanation..    You would dial up your internet provider (ISP),  that was often some local company with local phone number (you paid for long distance calls back then). or something like AOL

 

Then you and your ISP would use a protocol known is PPP or SLIP to communicate.    This basically encapsulated the internet protocol aka TCP/IP..   you got an IP address and to all internet-aware applications, you were connected   These applications don't care about how you got connected... could be ethernet, phone line, satellite or even sending packets via pigeon,  as long as you have an IP address and a way to route packets through a gateway, they could do the rest.

 

Finding google was just doing a DNS lookup for www.google.com and optaining an IP for google, same as it is now.    The dial-up modem just made it slower.

 

EDIT:   I will add that it was kind of mind-blowing when I first got a PPP connection, and got it working (it wasn't self-explanatory in 94, a lot of the terminology was new to me)  Before that direct internet access and IP networking was something only large organizations could afford.   Now most of us have IP networks in our homes!   Then another mind-blowing moment was when someone told me I could download Netscape Navigator (early web browser) completely for free and run it with my PPP connection.  Suddenly I was able to browse the graphical web from home!

Edited by zzip
  • Like 1

Share this post


Link to post
Share on other sites

Internet access works the same no matter what.  On a dial-up modem, you use an app that dials the ISP's number and logs in with your username & password through regular phone lines.

 

With broadband your DSL or cable modem does all of that automatcially over seperate signals carried over phone or cable TV lines, and far faster as well. Same with smartphones that use 4G/5G signals...

 

 

  • Like 1

Share this post


Link to post
Share on other sites
Posted (edited)

well.. yes and no.

 

dialup modems just create the physical layer. Like all network transports, it is not really accurate to call it the physical layer though.

 

The modem pair create a sychronous communication channel over the telephone lines, with added error correction and recovery, at a negotiated line speed. This is a 1:1 pairing with a remote modem.  They do this by modulating a carrier frequency using a known shared modulation schema. (this is where different modem flavors play in.)

 

With a BBS, this is just fine:  It works just like a serial connection after being established, with the modems doing the translation to and from the modulation schema transparently to the user and any connected applications.

 

For dialup internet however, actual IP protocol is routed on top of another protocol, the Point to Point Protocol, or PPP.  This is because IP protocol is not really intended for 1:1 connections.  The PPP transport functions kinda-sorta like a network switch, and restricts traffic not intended for that channel from traversing that channel, while also assuring that actual IP style network clients upstream can get all the data transmitted from the PPP connection, like IP networks expect, and also serving some 'proxy server' like functions.

 

PPP can/could be used in this way with any 1:1 paired transport, not just dialup modems. That included direct serial, microwave dish uplinks, et al.

 

 

It is important to point out that very early in the history of the consumer internet, PPP and IP networking stacks were **NOT** part of the operating system. Microsoft's OSes did not have native functions to handle modems or internet connections built in until windows 95, and then they were still very immature.

 

In the win3x days, you had to use a 3rd party dialer app, and have some other goodies loaded and set up, to use a dialup modem with your free copy of netscape. :)

 

A very commonly used one was WinSock PPP.

 

https://org.coloradomesa.edu/~jerry/systeminfo/ppp.win31.html

http://www.steptail.com/guides:connecting_windows_3.1_to_the_internet

 

You started winsock PPP first, and it handled your modem, dialed your ISP, established the PPP connection, got you an IP address, and then "you were on the internet", but you still had to open your browser after the fact.

 

Later versions of Netscape integrated the functions of Winsock PPP and pals, so they could dial all by themselves- but that quickly become obsoleted and culled, once microsoft started integrating dialup networking components into the OS-- the browser could simply tell the OS to "dial this connection for me", and the OS would handle it. (sometimes.)

 

By the end of the 90s, and early 2000s, ADSL and cable modems were starting to become a thing, and always-on internet was becoming a reality.  Such functions as dialup networking are now legacy footnotes in the annals of internet history.

 

 

On the mac side of things-- you had to use applications similar to winsock ppp with OS system versions 6.x, but had a PPP os extension for system 7.

 

https://www.radford.edu/~helpdesk/ppp/Macintosh/index-7.5.html

https://kb.iu.edu/d/adaq

 

  Netscape navigator and communicator 3 could latch onto that PPP extension, and dial for you.  The PPP extension wanted to know what mac serial port you were using, or-- if you were so fortunate-- what modem addin card you had-- what your ISP's username and password were (needed to negotiate PPP), what the number to dial was, what line speed to use, etc.

 

Mac serial ports of the time were proprietary things, so you had to have either special adapters, or special mac-oriented modems.

mac-serial-ports.jpg?w=224&ssl=1

 

 

 

 

 

 

Edited by wierd_w
  • Like 2

Share this post


Link to post
Share on other sites
13 hours ago, wierd_w said:

It is important to point out that very early in the history of the consumer internet, PPP and IP networking stacks were **NOT** part of the operating system. Microsoft's OSes did not have native functions to handle modems or internet connections built in until windows 95, and then they were still very immature.

Even Windows 95 didn't install it by default.  (at least not vanilla, pre-Service Pack Win95).    It was on the CD, but you had to know which components to add to make it work.

 

Linux distributions even back then came with all the tools to initiate PPP/Slip connections, but it was far from self-exploratory how to run it.

 

When I got my first Internet dial-up,  I was still on Atari ST, but was in the process of looking into getting a PC.

I used KA9Q on the Atari ST-   this was pretty limited in what it could do, but I think I mostly used it for FTP.   When I got my PC built, I was using Trumpet Winsock on Windows 3.1,  and eventually got pppd working correctly on (Slackware) Linux.

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...