What is the difference between SLIP and PPP?

Answer 1

SLIP is called Serial Line internet Protocol and PPP is the acronym of Point-to-Point Protocol.

Multi-ProtocolsPPP has some additional benefits. Unlike SLIP (which can only transport TCP/IP traffic), PPP is a multi-protocol transport mechanism. This means that PPP not only transports TCP/IP traffic, but can also transport IPX and Appletalk traffic, to name just a few. Better yet, PPP lets you transport all of these protocols at the same time - on the same connection.

This is often not a concern for most users since their purpose of either using SLIP or PPP is to connect to the internet and the internet uses TCP/IP only. Therefore, there is no need to transport other protocols.

Configuration NegotiationWith SLIP, you have to know the IP address assigned to you by your service provider. You also need to know the IP address of the remote system you will be dialing into. If IP addresses are dynamically assigned (depends on your service provider), your SLIP software needs to be able to pick up the IP assignments automatically failing which you have to setup them up manually. You may also need to configure such details as MTU (maximum transmission unit), MRU (maximum receive unit), use of VJ compression header (ie., CSLIP), etc. All these can get confusing pretty fast.

PPP addresses this problem by negotiating configuration parameters at the start of the connection. This can greatly simplify the configuration of your PPP connection.

Automatic LoginMost SLIP/PPP software can dial-up and automatically login for you. However, they often depend on your service provider's system sending out standard prompts (eg, "login:" to get the login name and "password:" to get the password). If they are any way non-standard, you either need to write a script to automate the login process yourself or login manually in the terminal emulation mode of your SLIP/PPP software.

PPP provides two methods with which logins can be automated - PAP (Password Authentication Protocol) and CHAP (Challenge-Handshake Authentication Protocol). Both provide the means for your system to automatically send your login userid/password information to the remote system.

Answer 2

SLIP

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Serial Line Internet Protocol (SLIP) is an old protocol which was used to handle TCP/IP traffic over a dial-up or other serial connection. SLIP is a physical layer protocol that doesn't provide error checking, such as modem error checking. It only supports the transmission of one protocol, TCP/IP.

A later version of SLIP, called compressed SLIP (CSLIP), became available. The CSLIP protocol reduces the amount of information in the headers from 20 bytes to 7 bytes, and does not compress the transmission.

PPP:

Point to point protocol (PPP) is much more robust than its earlier cousin, SLIP. PPP provides a physical and data link layer functionality that fixes many problems with SLIP. At the data link layer, PPP provides error checking to ensure the accurate delivery of the frames that it sends and receives. PPP also keeps a logical link control communication between the two connect devices by using the Link Control Protocol (LCP). PPP supports the dynamic configuration of the dialed-in computer.

Unlike SLIP, in which addresses and other information have to be hard-coded ahead of time, PPP allows the client computer to receive its information from the host it dials into. Most internet dial-up connections today are made using PPP over modem or ISDN.

While PPP is widely-used today, SLIP still has some uses, mainly in Bluetooth devices.