1.6 Distinguish whether SLIP or PPP is used as the communications protocol for various situations.

 

PPP and SLIP are both data link protocols that can be used for remote accessing the network.

SLIP (Serial Line IP) is a remote access protocol provides dial-up access to TCP/IP network. It transmits IP packets over serial connections. You can implement a SLIP server or a SLIP client in the network. However, none of Microsoft's operating system such as Windows 95 or Windows NT supports SLIP server solution. SLIP is implemented as a client solution in Windows 95 and Windows NT for two purposes:

 

Because the only network protocol supported by SLIP is TCP/IP, it requires fewer overheads than PPP. However, because SLIP lacks some features such as compression, dynamic IP address assignment as well as encryption, it is gradually being replaced by PPP. CSLIP (Compressed SLIP) provides the compression for the communication. However it is different from the SLIP. Therefore in the Networking Essentials exam, you can only consider SLIP as a protocol doesn't support compression.

PPP, Point-to-Point Protocol, is a remote access protocol that provides dial-up access over serial lines. PPP supports several network protocols include NetBEUI, TCP/IP and IPX/SPX. PPP not only supports data compression but also provides password protection using PAP (Password Authentication Protocol) and CHAP (Challenge Handshake Authentication Protocol.

The Windows NT 4.0 and Windows 98 system can be either a PPP remote access client or a PPP remote access server. The Windows 95 system can be easily configured a PPP client, however Microsoft Plus! or new Dial-up networking component (You can download it from Microsoft’s web site) must be installed to let a Windows 95 system perform as a PPP server.

Most Internet Service Providers prefer to use PPP in that it supports dynamic IP assignment, which simplifies the IP address management and escapes the problem that must assign a dedicated IP address to a user in SLIP and save the IP addresses.

PPP can transfer IP, IPX, and NetBIOS data at the same time, whereas SLIP can only transfer IP data. However, since IP is the only protocol used on the Internet (and private Intranets), this capability has little relevance for most users.

PPP has error detection features built into the protocol. This means that if a data packet were corrupted when it was sent between two computers connected with PPP, the receiving computer would immediately be aware of the error and discard the packet. The sending computer would eventually re-send the packet. SLIP protocol uses a less sophisticated error recovery scheme than PPP, but since errors happen so rarely, SLIP is not measurably less reliable.

If somebody ask you that SLIP or PPP which protocol requires the less overhead, the answer should be SLIP.