PPP Definition | The Interactive Glossary

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If you receive Internet access over phone lines, there's a very good chance that connection is made possible by Point-to-Point Protocol. Internet Service Providers (ISP) often use PPP to offer dial-up internet access, and they may also use PPP derivatives to offer DSL connections.

PPP is one of several link layer protocols belonging to the Internet protocol suite that can be used to establish Internet connections. Link layer protocols are used, among other things, to negotiate the connection between an ISP and a customer.

Also See: Protocol, DSL, Dial-Up

Frequently Asked Questions

What is the difference between SLIP and PPP?

Serial Line Internet Protocol (SLIP) was a predecessor to PPP. SLIP has been rendered obsolete by PPP and is not used to establish Internet connections over phone lines anymore. But what were the actual differences between SLIP and PPP? Why was PPP adopted while SLIP was deprecated? There are at least three major ways in which PPP and SLIP differ:

• First, PPP is able to auto-detect connection settings, while SLIP settings have to be manually configured prior to establishing a connection. This meant that PPP was much easier for consumers to use, and reduced the technical burden placed on ISPs.
• Second, PPP supports error detection and the recovery of lost data packets. SLIP, on the other hand, was not capable of detecting errors, meaning that error detection had to be handled by other protocols. Once again we see that switching to PPP reduced the technical burden placed on ISPs.
• Third, the single advantage offered by SLIP is its simplicity. SLIP requires only minimal network resources, where PPP carries significantly higher overhead. As a result, SLIP is still used in some niche applications, such as in microcontrollers, where it's shortcomings are not problematic.

In summary, switching from SLIP to PPP made the ISPs' job easier, and it also made it easier for individual consumers to use Internet connections.

When was PPP developed?

According to the TCP/IP Guide, the first formal document related to PPP was a proposal that outlined the basic PPP architecture, and was published in 1989. The first formal PPP standard was released a year later, and has undergone a number of revisions and updates through the years.

When SLIP was developed in the early 1980s, it was designed to be a short-term fix. It was never intended to gain permanent acceptance as a standard. The shortcomings we mentioned earlier were sufficient to undermine SLIP's usability as a long-term standard right out of gate, and though broadly adopted, SLIP was never officially documented as a standard. PPP was developed out of this felt need to have a protocol that was robust enough to be used as a long-term standard for negotiating connections between a physical serial connection and an ISP.