Learning outcome
           Definitions for network
           Review for OSI Network model
           Security triad
           The Challenges of Computer Security
                                 Network Definitions
                                    Network  explained as an arrangement of intersecting horizontal and 
                                     vertical lines.
                                    "a spider constructs a complex network of several different kinds of 
                                     threads"
                                 Network Definitions
                                    Data network is a digital telecommunications network which 
                                     allows nodes to share resources
                                    A computer network is a set of connected computers. 
                                     Computers on a network are called nodes. 
        Open Systems Interconnection (OSI) Model
                                 Computer Security
                                    The NIST Computer Security Handbook [NIST95] defines the term 
                                     computer security as follows:
                                    The protection afforded to an automated information system in 
                                     order to attain the applicable objectives of preserving the 
                                     integrity, availability, and confidentiality of information system 
                                     resources (includes hardware, software, firmware,  
                                     information/data, and telecommunications).
                                              https://www.nist.gov/