A set of network protocol layers that work together to provide the services on a communications network is called a protocol stack. The stack is a conceptual representation of the role each protocol plays relative to another protocol. Each layer in a protocol has a function and represents a step in a hierarchical structure. The figure below shows the TCP/IP protocol stack, with the remote access protocols at the top of the hierarchy.
Remote access protocols allow users to connect to another computer via distant or local networks and access files or data.
The following diagram displays the various protocol layers:

Protocol Stack

Communication protocols

Protocol	Characteristics
(PPP) Point-to-Point Protocol	Provides dial-up access over serial lines and automatic login and configuration negotiation
(PPTP) Point-to-Point Tunneling Protocol	1.Allows data in TCP/IP format to be transmitted over a non-TCP/IP network Can be used to set up a VPN virtual private network, but is only available on networks served by Windows 2008 or later
(SLIP) Serial Line Internet Protocol	1. Provides access to the Internet or dial-up access between two LANs. 2. Older and not as well-designed as PPP.

In the next lesson, the network requirements necessary to meet business goals for a Web site development project will be discussed.

Protocols and Addresses Quiz