Dial-up networking uses a method called PPP Point to Point Protocol to package data for transmission over phone lines. As with ethernet, the PPP data packet, often called a frame, includes several parts.
There are beginning and ending flags called "wrappers" that bound the packet. Just like ethernet packets , PPP frames contain wrapper upon wrapper. One important distinction between PPP frames and ethernet packets is the capacity of damaged PPP packets to be recovered using a process called the frame check sequence.
A packet occasionally gets lost or damaged en route; when it arrives at its destination, a damaged ethernet packet gets thrown out and a request goes back to the computer that sent the packet to resend it--a very time-consuming process if you use a dial-up connection, which is much slower than broadband. In contrast, one part of a PPP wrapper contains a chunk of data called the validation value, which is verified at the destination. In some cases, a damaged PPP frame can be restored through the validation value, so it does not need to be resent.
While this process saves valuable time that would otherwise be used to resend every damaged packet, PPP's error-recovery features tend to make PPP run a bit more slowly than the simpler protocols that lack such error correction. But the Internet is a dangerous place for a data packet; errors or other problems can cause dozens of packets to drop each second.
In the long run, PPP is far better suited to use over the Internet than other, less stringent protocols, so it has survived and flourished. Virtually every Internet service provider uses dial-up networking to connect individuals to the Internet.
Most recognizable are the larger, international information services and ISPs. Each of the big guns offers its own brand of interface, built on dial-up networking, with varying levels of customization and proprietary features. But there are often a few gotchas if you use an information service's customized interface: Some limit the user's access to Internet resources that are not part of the service's offerings.
America Online, for instance, boasts the greatest number of subscribers among ISPs and information services. AOL offers those subscribers a wide range of clubs, user groups, and file libraries. There's so much to do that many AOL subscribers know only how to use those features and services exclusively within AOL's borders, rendering them unable to "leave the nest," so to speak.
On the other hand, more and more subscribers would prefer to use such subscriptions only to connect to the Internet. Smaller, local ISPs frequently offer more competitive rates, less restrictive interfaces, and a different selection and usually a higher standard of service options.
Often they use the same "head-end" network, such as the GRIC Alliance , as the largest providers do, and this can give local ISPs nationwide or even worldwide access numbers. By: Satish Balakrishnan. Dictionary Dictionary Term of the Day. Gorilla Glass.
Techopedia Terms. Connect with us. Sign up. Term of the Day. Best of Techopedia weekly. It's only accessed when that 'phone call' is made, and each time you access it, you're charged, which makes it quite expensive. In addition, because dial-up uses normal phones lines, its speed and efficiency can be compromised.
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