An Introduction to Computer Networking

Objectives Identify elements of a network Describe several specific uses of a network Distinguish between client/server and peer-to-peer networks 11/18/2018 CIS275

Networks and Standalone Computers Group of computers and other devices connected by some type of transmission media Networks enable users to share devices and data, collectively called a network’s resources Standalone computer Uses programs and data only from its local disks and is not connected to a network 11/18/2018 CIS275

Local and Remote Computers Local computer Computer on which user is working Remote computer Computer that user controls or works on via network connection 11/18/2018 CIS275

Simple peer-to-peer network Computers communicate on single segment of cable and share each other’s data and devices Simple example of a local area network (LAN) Simple peer-to-peer network 11/18/2018 CIS275

Local Area Network (LAN) Network of computers and other devices confined to relatively small space LANs involving many computers are usually server-based On a server-based network, special computers (known as servers) process data for and facilitate communication between other computers on the network (known as clients) 11/18/2018 CIS275

Networking Basics Workstation Client/server architecture Computer that typically runs a desktop operating system and connects to a network Client/server architecture Networking model in which clients use central server to share applications, devices, and data 11/18/2018 CIS275

Networking Basics Client/server network Network operating system Network based on client/server architecture Network operating system Special software designed to manage data and other resources on a server for a number of clients 11/18/2018 CIS275

Networking Basics LAN with a file server 11/18/2018 CIS275

Advantages of Server-Based over Peer-to-Peer Networks User login accounts and passwords can be assigned in one place Access to multiple shared resources can be centrally granted Servers are optimized to handle heavy processing loads and dedicated to handling requests from clients Servers can connect more than a handful of computers 11/18/2018 CIS275

MANs and WANs Metropolitan area network (MAN) Wide area network (WAN) Network connecting clients and servers in multiple buildings within limited geographic area Wide area network (WAN) Network that spans large distance and connects two or more LANs The Internet is an example of a very intricate and extensive WAN that spans the globe 11/18/2018 CIS275

WAN A simple WAN 11/18/2018 CIS275

Elements Common to All Server-Based Networks Client In addition to referring to a computer on the network, may also refers to human user of client workstation Server Workstation Network interface card (NIC) Enables workstation to connect to the network and communicate with other computers 11/18/2018 CIS275

Elements Common to All Server-Based Networks Network operating system (NOS) Host Server that manages shared resources Node Client, server, or other device that can communicate over a network and that is identified by a unique identifying number, known as its network address 11/18/2018 CIS275

Elements Common to All Server-Based Networks Topology: It is the physical layout of computer network Commonly used network topologies are: 11/18/2018 CIS275

Elements Common to All Server-Based Networks Protocol Rules network uses to transfer data Data Packets The distinct units of data transmitted from one computer to another on a network Addressing Scheme for assigning unique identifying number to every workstation on network The number that uniquely identifies each workstation and device on a network is its address 11/18/2018 CIS275

Elements Common to All Server-Based Networks Transmission media Means through which data are transmitted and received 11/18/2018 CIS275

How Networks Are Used Services Features provided by a network File and print services Communications services Mail services Internet services Management services 11/18/2018 CIS275

Network Services File services Print services Refers to capability of a server to share data files, applications, and disk storage space Server that provides file services is called a file server Print services Allows printers to be shared by several users on a network 11/18/2018 CIS275

Network Services Communications services Allow remote users to connect to a network Remote user Person working on a computer in a different geographical location from the LAN’s server Communications server Server that runs communications services Also referred to as access servers and remote access servers 11/18/2018 CIS275

Network Services Mail services Internet services Coordinate storage and transfer of e-mail between users on a network Gateway Combination of software and hardware enabling two different kinds of networks to exchange data Internet services Enable networks to communicate with the Internet 11/18/2018 CIS275

Network Services Management services Centrally administer and simplify complicated management tasks on the network Numerous services fall under category of network management 11/18/2018 CIS275

Important Management Services Traffic monitoring and control Traffic Data transmission and processing activity taking place on a computer network at any given time Segment Part of LAN that is logically separated from other parts of LAN and that shares fixed amount of traffic capacity 11/18/2018 CIS275

Important Management Services Load balancing Distributing process activity evenly across a network so that no single device is overwhelmed Hardware diagnosis and failure alert Determining when a network component fails and automatically notifying network administrators through e-mail or pager 11/18/2018 CIS275

Important Management Services Asset management Collecting and storing data on number and types of software and hardware assets in an organization’s network License tracking Determining how many copies of a single application are currently in use on a network 11/18/2018 CIS275

Important Management Services Security auditing Evaluating what security measures are currently in force and notifying network administrator if a security breach occurs Software distribution Automatically transferring data file or program from the server to a client on the network 11/18/2018 CIS275

Important Management Services Address management Centrally administering a finite number of network addresses for an entire LAN Backup and restoration of data Backing up Copying critical files to a secure storage area Restoring Retrieving data if original files are lost or deleted 11/18/2018 CIS275