CertiGuide to Network+  9  Chapter 0111: Wide Area Networking

Remote Access Dial-up Protocols 1 SLIP

Because of these new needs for running TCP/IP over dial-up lines, several new protocols, called TCP/IP encapsulation protocols, were developed to network over relatively slow dial-up lines as efficiently as possible, while also providing the needed authentication and compatibility negotiation (speed, features, etc.). They’ are referred to as encapsulation protocols because the TCP/IP packets are contained within outer packets which are used by these remote access protocols for signaling, control, error correction, data compression, etc. When the “sending” remote communication device receives a packet bound for the Internet, it adds the remote access protocol packet around it and transmits the new packet, which is then picked up by the “receiving” remote communication device which unwraps the packet and puts the sender’s original raw TCP/IP packet on the network, as if the sender was directly connected to the network.

To support virtual private networks, there are even protocols with built-in connection tunneling and encryption for data privacy, usable over dial-up connections.

Four encapsulation protocols are testable in the NETWORK+ test. They are:

1. SLIP (Serial Line Internet Protocol)
   
   
2. PPP (Point To Point Protocol)
   
   
3. PPTP (Point To Point Tunneling Protocol)
   
   
4. L2TP (Layer 2 Tunneling Protocol)

Remote Access Dial-up Protocols 1 SLIP