Dial-Up Networking: a set of protocols and software used to connect a computer to the internet service provider (ISP), online service or a remote computer, through an analog modem and POTS (plain old telephone system).
Dial-up networking is a type of computer connection to the Internet's most widely used. In late 2000, more than a quarter billion subscribers to dial into the Internet - four times more than other popular access methods, such as broadband DSL, cable modems, and ISDN. Here are a few things you need to know:
Dial-up networking using a modem as an interface between a PC with a network like the Internet; modems usually have a speed of up to 56 kbps.
Dialing with a modem is still the cheapest way of internet access and most widely available. But because it has a relatively slow speed, sites rich in graphics take a long time to load.
The maximum speed in downloading data using a dial-up networking is limited to the phone system's analog bandwidth, line quality, and Internet traffic.
Dial-up networking usually communicates with the ISP using the Point to Point Protocol.
While broadband services like DSL, cable modems, and satellite, is widely available throughout the world, dial-up networking continues to grow. It is estimated that wireless connectivity will face the biggest challenge of dial-up networking in terms of subscribers in the future. In fact, analysts predict, at the end of 2001, people who use dial-up networking are two times more than those who use the service boradband to connect to the internet. In 2003 the gap will close, but dial-up networking is still the most popular way, with a ratio of 1:1.5.
Does A "Handshake"
Dial-up networking is the simplest way to connect to the internet: you only need to connect to your telephone line using a modem, if you are already subscribed to an ISP. Most likely, the software tools you need already exist on Windows, some ISPs, like Earthlink, furnish a user interface for easy setup. Whichever method is used, the dial-up customers usually only need to enter a user name and password, in addition to the ISP's phone number, to the dialog box that appears. Software dial-up networking using the information to build a connection with ISP and doing other work. After setup, which customers need to do is build a connection with double-clicking an icon.
When you do the "handshake", the dial-up networking modem first directs you to the ISP's phone number, which is answered by another modem at the other end. For a few seconds the modems send each other control signals to determine how fast each one can connect. Screeching you hear when you first connect the modem is the sound of your modem and the modem ISP "harmonize" the connection and determine the speed used.
If the connection is established, your modem will silence the internal speaker, and dial-up networking to send user name and password to the ISP using a process called CHAP (challenge handshake authentication protocol). At the ISP, a computer checks your user name and password against a database of consumers. If the ISP authenticates your information, the status of dial-up networking window disappears, and you are free to surf, check and send e-mail, download files, and so forth. The process can take anywhere from 30 seconds to 2 minutes.
Little More Slow, But Reliable
Dial-up networking as well break your data into chunks, encode it, and repacking the data before sending.
Dial-up networking using a method called PPP (Point to Point Protocol) to package the data to be sent through phone lines. Just as Ethernet, PPP data packets, often called a frame, consisting of several parts. There are beginning and end (called "wrappers" or wrapper) that bind the package. Just as Ethernet packets, the PPP frame contains a wrapper in the wrapper. Packaging help direct the data in the packet to its destination using different protocols, like TCP / IP, and also determine the type of data compression used on the package.
One important distinction between PPP frames and ethernet packet is the capacity of the repaired damaged PPP packet using a process called frame check sequence. A package is usually lost or damaged en route, when he arrived at his destination, a damaged ethernet packets discarded and demand will return to the computer that sent the packet to send it back - a very time-consuming process if you use a dial-up, which is much slower than broadband.
In contrast, one part of a PPP wrapper contains a chunk of data called the validation value or the value of validation, which is verified at the destination. In some cases, PPP frames are damaged can be restored through the validation, so no need to be sent back.
If this process saves valuable time that would otherwise be used to send back any damaged package, error-recovery features tend to cause the PPP PPP work slower than a simpler protocol, which has no such error correction. But the internet is a dangerous place for packet data, errors or other problems can cause dozens of packets every second. In the long run, PPP is more suitable for the Internet protocol that is more flexible than others, so it has survived and flourished.
Still Survive - To Present
Any ISP using dial-up networking to connect a computer to the Internet. The most easily recognizable is the national information service and a large ISP. Companies like America Online, EarthLink, AT & T WorldNet, and MSN are the names of which are well known in the past 10 years, and offering services to almost all U.S. (and often provides international access as well). Each of these companies offer interface and dial-up networking built-on its own, with various levels of customization and feature complement.
But often there are some obstacles if you use the interface ISPs: some ISPs restrict access to Internet users who are not part of the bid. America Online, for example, claim to have the largest number of subscribers compared to ISPs and other information services. AOL offers its customers a wide selection of clubs, user groups, and a series of files. So many things to do, so many AOL subscribers only know how to use features and services within the limits established by AOL. This causes them to not get away from AOL.
On the other hand, more and more customers are choosing to use this kind of subscription-only to connect to the dorm. You, for example, can directly use AOL as an ISP, but only a few users who do so.
Small ISPs, Great Service
Small local ISPs typically offer more competitive services, the more non-binding interface, and a variety of different services. "Local" does not mean they are limited geographically. Often they also use the network head-end the same, such as GRIC Alliance, which used a large ISP. And this network provides national access number (even international) to the local ISP. Earthlink and MSN, for example, uses the same network, as well as other small ISPs.
There is also a free ISP, which offers basic connection via the user interface. The tendency, free ISP presents a lot of ads on its interface, and little or no technical support at all if there is a problem. Recently, this kind of service started to charge for their services.
Bright Future
Dial-up networking is a mature technology; over the years, the development of existing technology have improved performance, but not accompanied by adequate amounts. Development of dial-up networking significantly recently is the launch of the V.90 standard, which allows the modems that are used in the two previous standards are not compatible, interconnected. As a result, most modems can be connected with a maximum rate of 56 kbps.
(56K-bps modem specifications, in fact, only translated 52K-bps, and the average maximum of 40K-bps throughput. The quality of copper phone wires and phone jacks are used, the distance the user from the telephone company central office, and internet traffic density and a site, determine the quality of the connection.)
A new standard, called V.92, promising increased upstream rate using pulse code modulation, a more efficient way to retrieve and package the data for transmission. The standard also adds convenience features. With V.92, users who subscribe to the call-waiting service from your telephone company will be able to take a call without losing the connection to the internet. Other V.92 feature, called Quickconnect, given the information "handshake" between your modem with dial-up service, saving connection time is almost half.
With compression technology in sight that promises improved performance using smaller cables and convenience features V.92, seems to dial-up networking will be increasingly on the rise, at least for now.
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