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Transcript
Chapter 1 An Introduction to Networking Collected and Compiled By JD Willard MCSE, MCSA, Network+, Microsoft IT Academy Administrator Computer Information Systems Instructor Albany Technical College Attention: Accessing Demos • This course presents many demos. • The Demos require that you be logged in to the Virtual Technical College web site when you click on them to run. • To access and log in to the Virtual Technical College web site: – To access the site type www.vtc.com in the url window – Log in using the username: CIS 1140 or ATCStudent1 – *Enter the password: student • If you should click on the demo link and you get an Access Denied it is because you have not logged in to vtc.com or you need to log out and log back in. *Remember that passwords are case sensitive so enter it in all lower case letters. Objectives • List the advantages of networked computing relative to standalone computing • Distinguish between client/server and peer-to-peer networks • List elements common to all client/server networks Why Use Networks? • Network: group of computers and other devices that are connected by some type of transmission media • Commonly connected devices include microcomputers, minicomputers, mainframe computers, terminals, printers, fax machines, pagers, and various data storage devices • Advantages of using networks over standalone computers: – Networks enable multiple users to share the network’s resources (devices and data) – Networks allow you to manage, or administer, resources on multiple computers from a central location What Is A Network Demo What Are the Benefits of Computer Networking? • Powerful, Flexible Collaboration • Cost-Effective Resource Sharing • Secure Management of Sensitive Information • Effective Worldwide Communications • Easy, Immediate Information Dissemination • Worldwide, Instantaneous Access to Information Types of Networks: Peer-to-peer Networks • Simple to configure and relatively inexpensive • Every computer can communicate directly with every other computer • By default, no computer has more authority than another • No centralized security. Security is maintained on each individual computer (decentralized security model) • Every computer is capable of sending and receiving information to and from every other computer Network Models Demo Peer-to-peer Networks •No dedicated server or hierarchy, also called a workgroup. •NUsually 10 or fewer workstations. ot very flexible or scalable. •Users act as their own administrator and security which makes them relatively unsecure. •Computers are in same general area. •Limited growth. Resource sharing on a simple peer-to-peer network Peer to Peer vs. Server Centric Demo Client/Server Networks • The most popular type of network for medium- and large-scale organizations • Client/server network: uses a server to enable clients to share data, data storage space, and devices • Server: central computer used to facilitate communication and resource sharing between other computers (called clients) on the network (centralized security model) • To function as a Server, a computer must be running a network operating system (NOS) – Manages data and other resources for a number of clients – Ensures only authorized users access the network – Controls access to resources – Restricts when and from where users can access the network – Supply applications to clients Client/Server Networks •10 or more users. •Employs specialized servers. –File and Print –Application –Mail –Fax –Communications (gateways) •Central administration. •Greater security. •Centralized backup. •Data Redundancy. •Supports many users Resource sharing on a client/server network Client/Server Networks • Advantages of using client/server networks over peer-to-peer networks: – User logon accounts and passwords can be assigned in one place – Access to multiple shared resources can be centrally granted to a single user or groups of users – Problems can be tracked, diagnosed, and often fixed from one location – Servers are optimized to handle heavy processing loads and dedicated to handling requests from clients, enabling faster response time – Because of their efficient processing and larger disk storage, servers can connect more than a handful of computers on a network LANs Local Area Networks Network Categories Demo • Local area network (LAN): confined to a relatively small space, such as a building or an office • Typically connects computer in a single building or campus. • Developed in 1970s. • Medium : optical fibers, coaxial cables, twisted pair, wireless. • High speed networks • Typically buses or rings. • Ethernet, Token Ring MANs Metropolitan area network • Larger than a LAN; connects clients and servers from multiple buildings • Generally covers campuses or office complexes – Connects clients and servers from multiple buildings • Developed in 1980s • Medium : optical fibers, twisted pair cables • Data rates adequate WANs Wide area network • Connects two or more geographically distinct LANs or MANs • Developed in 1960s. • Generally covers large distances (states, countries, continents). • Medium : communication circuits connected by routers. • Routers forwards packets from one to another following a route from the sender to the receiver. Store-and-Forward • Hosts are typically connected (or close to) the routers LANs, MANs, and WANs A simple WAN Elements Common to Client/Server Networks • • • • • • • • Client – A computer on the network that requests resources or services from another computer on a network. Server – Run operating software that can manage not only data, but also users, groups, security, and applications on the network Workstation – A personal computer which may or may not be connected to a network. Network interface card (NIC) – The device inside a computer that connects a computer to the network media NOS – Software that runs on a server and enables the server to manage data, users, groups, security, and applications on the network Host – A computer that enables resource sharing by other computer on the same network Node – A computer or other device connected to a network Connectivity device – a specialized device that allows multiple networks or multiple parts of one network to connect and exchange data Network Requirements Demo Elements Common to Client/Server Networks A NIC Elements Common to Client/Server Networks • • • • • • • Segment – Usually composed of a group of nodes that share the same communications channel for all their traffic Backbone – The part of a network to which segments and significant shared devices connect. Topology – The physical layout of a computer network Protocol – A standard method or format for communication between networked devices Data packets – The distinct units of data that are exchanged between nodes on a network Addressing – The scheme for assigning a unique identifying number to every node on the network Transmission media – The means through which data is transmitted and received Elements Common to Client/Server Networks A LAN backbone Elements Common to Client/Server Networks Common network topologies Demo Elements Common to Client/Server Networks Examples of network transmission media Summary • A network is a group of computers and other devices that are connected by some type of transmission media • In a peer-to-peer network, every computer can communicate directly with every other computer • A client/server network uses a server to enable clients to share data, data storage space, and devices • A LAN is confined to a relatively small space, such as a building or office Summary • A MAN is larger than a LAN and connects clients and servers from multiple buildings • A WAN connects two or more geographically distinct LANs or MANs • Elements common to client/server networks: client, server, workstation, NIC, NOS, host, node, connectivity device, segment, backbone, topology, protocol, data packets, addressing, and transmission media The End