Network Basics

1. Network Basics

2. Outline • Objective • Types of Networks • LAN Topologies • LAN Networking Standards • Network Devices • Dial-Up Access • Ethernet Wiring • Summary • References

3. Objective • To provide a basic understanding of how our computers are connected together via a network.

4. Types of Networks • LAN – A Local Area Network is a computer network covering a small geographic area, like a home, office, or group of buildings. • Each node (computer) on the LAN has its own computing power but can also access other devices on the LAN subject to the permissions it has been allowed. These could include data, processing power, and the ability to communicate or chat with other users in the network. • The defining characteristics of LANs include their high data transfer rates, small geographic range, and lack of a need for leased telecommunication lines • MAN – Metropolitan Area Networks are large computer networks usually spanning a city. They may use wireless infrastructure or optical fiber connections to link their sites. • As with LANs, MANs also use communications channels of moderate-to-high data rates • Might be owned and operated by a single organization, but usually used by many individuals and organizations

5. Types of Networks • WAN – Wide Area Network is a computer network that covers a broad area (i.e., communications links cross metropolitan, regional, or national boundaries). • Less formally, a network that uses routers and public communications links • Used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other locations

6. LAN Topologies • Bus Topology • Ring Topology • Star Topology http://fcit.usf.edu/network/chap5/chap5.htm http://www.computerhope.com/jargon/r/ringtopo.htm

7. LAN Networking Standards • Ethernet • A large, diverse family of frame-based, multiple access computer networking technologies that operates at many speeds (IEEE 802.3) • Defines a number of wiring and signaling standards for the physical layer, through means of network access at the Media Access Control (MAC)/Data Link Layer, and a common addressing format • May be used over Twisted Pair, Coaxial Cable, Fiber Optic Cable, etc. media • Token Ring • Initially very successful, it went into steep decline after the introduction of Ethernet in the early 1990s (IEEE 802.5) • Wireless Fidelity (WiFi) (We will talk more about this later) • Wireless LAN standard (IEEE 802.11), used in place of (and in addition to) Ethernet for many home and small office networks

8. LAN Topologies & Networking Standards • These topologies have a physical and logical component • Bus Topology implies a shared access mode (such as used by Ethernet) • Ring Topology implies a token sharing access mode (such as used by Token Ring) • Star Topology is the actual physical method by which most wired networks are connected

9. Network Devices • Network Interface Controller (NIC) • Computer hardware that allows computers to communicate over computer network using cables or wirelessly. It provides physical access to a networking medium and provides a low-level addressing system. • Hub • A device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act as a single segment • Switch • A networking device that performs transparent bridging (connection of multiple network segments) at up to the speed of the hardware

10. Network Devices • Cable Modem • A type of modem that provides access to a data signal sent over the cable television infrastructure primarily used to deliver broadband Internet access • DSL Modem • Digital Subscriber Line • DSL or xDSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network • Wireless Access Point (AP) • A device that connects wireless communication devices together to form a wireless network, usually connects to a wired network to relay data between wireless devices and wired devices • Eliminates need to string cables and provides users with greater mobility

11. Dial-Up Access • A form of Internet access through which the client uses a modem connected to a computer and a telephone line to dial into an Internet service provider's (ISP) node to establish a modem-to-modem link, which is then routed to the Internet • Modem (Modulator-Demodulator) • Turns the digital '1s and 0s' of a personal computer into sounds that can be transmitted and received over telephone lines http://en.wikipedia.org/wiki/Dial-up http://en.wikipedia.org/wiki/Modem

12. Ethernet Wiring • Twisted pair cabling is a form of wiring in which two conductors are wound together for the purposes of canceling out electromagnetic interference (EMI) from external sources and crosstalk from neighboring wires • This cable has an RJ-45 jack on each end • It connects your PC to the wall (hub, router, etc.) http://en.wikipedia.org/wiki/Twisted_pair

13. Summary • This section provided a basic understanding of how our computers are connected together in a network

14. List of References • http://en.wikipedia.org/wiki/Local_area_network • http://en.wikipedia.org/wiki/Metropolitan_Area_Network • http://en.wikipedia.org/wiki/Wide_area_network • http://fcit.usf.edu/network/chap5/chap5.htm • http://www.computerhope.com/jargon/r/ringtopo.htm • http://en.wikipedia.org/wiki/Dial-up • http://en.wikipedia.org/wiki/Modem • http://en.wikipedia.org/wiki/Twisted_pair CyberPatriot wants to thank and acknowledge the CyberWatch program which developed the original version of these slides and who has graciously allowed their use for training in this competition.