A n n o u n c e m e n t s Computer Science 1A Introduction to Computer Science Topic 6 Networking Chapter 2 Part 2 C o m p u t e r N e t w o r k s What are networks Lab 3 Networking has been Posted Topic 6 Networking Ch 2 1 of 32 Why network computers To share resources Software Periphrials Data Etc How are they connected Either through wires or cables Wireless radio waves infrared signals celluar signals Topic 6 Networking Ch 2 E W t i h r e e r s n e t Quiz 4 Software and Networking History of Networking 2 or more computers that are linked together so that they can communicate with each other 2 of 32 Topic 6 Networking Ch 2 3 of 32 Developed in the 1970s at Xerox PARC Was the standard by the 1980s Originally used coaxial cable Then moved to twisted pair or 10 base T looks like a big telephone cable Included a protocol Set of rules for transferring data Most widespread wired Local Area Network LAN technology Topic 6 Networking Ch 2 4 of 32 A r e a N e t w o r k s Different types of networks based on the geographic area it covers Local area networks LANs A small group of computers nodes Home network or small company Topic 6 Networking Ch 2 5 of 32 1 Wide area network WANS Connects two or more LANs over a large geographical area W N i e d t e w o A r r k e s a cities states the world Small networks can communicate through each other using a gateways Gateway manages communication with other LANs One node on a LAN is designated as the gateway The Internet is the worlds largest public WAN 6 of 32 Topic 6 Networking Ch 2 S e r C v l e i r e n M t o d e l D i f f e r e n t o f s e r v e r t s y p 2 e s In this model a client sends a request to the server for software data or a printer the server processes the request and supplies the requested resources Server Client Client Client Client Topic 6 Networking Ch 2 8 of 32 D i f f e r e n t Manage requests for web pages Servers are often dedicated they perform only their server specific tasks Topic 6 Networking Ch 2 10 of 32 Two basic types of high level network design Client Server Model Most commonly used in business Started in the 1980s when PCs became more prevalent Different computers have different functions Computers share resources Peer to Peer Model More commonly used in home All computers tend to support the same function Topic 6 Networking Ch 2 computers attached to the network manage specific resources on the network o f T o p o l o g i e s 7 of 32 Servers Network servers Manages network traffic File servers Primary purpose is to manage files on the network Many users can access the same files Eliminates the need for multiple versions of the same file Dedicated to rapid storage and retrieval of shared data Topic 6 Networking Ch 2 N e t w o r k Web Servers s e r v e t r y s p e s Print servers Manage one or more printers Many users can access one printer N e t w o M r o k d e D l e s s i g n 9 of 32 The Topology represents the layout structure or configuration of the network from the point of view of data flow How are things hooked up Many Different types of topologies for example Bus Topology Star Topology Ring Topology Topic 6 Networking Ch 2 11 of 32 2 B u s T o p o l o g y T o R p i o n l g o g y Nodes computers communicate through a common conduit line I n t e r n e t T o p o l o g y Uses a single communication backbone or all devices Messages are carried in both directions Each node checks the address on the message and retrieves it if it is necessary otherwise ignores it The Ethernet is a very commonly used topology that is based on the bus topology Every thing is connected through a common line conduit or backbone Topic 6 Networking Ch 2 Either clockwise or counter clockwise Also referred to as token passing S t a r 12 of 32 All nodes are connected in a loop Messages travel in one direction through the ring Topic 6 Networking Ch 2 T h e All data flows through one centralized device like a hub or a switch Common in home networks All messages are sent through the centralized device If this is not function properly Nothing works Topic 6 Networking Ch 2 H o w d o c o m p u t e r s c o m m u n i c a t e 14 of 32 Wires Wireless Blocks of data called Packets are sent Agree to use the same protocols to communicate The protocol used on the internet is referred to as TCP IP Topic 6 Networking Ch 2 17 of 32 Need to agree upon what each bit means This is the particular language that must be decided upon Protocols are a set of rules that describe how data will be formatted and processed Uses the Internet Backbone A collection of high speed networks that handle internet traffic Companies provide this service These providers have connections that provide a high transfer rate How much data will be sent at one time Ethernet Wires A very large WAN Need to agree upon how will they physically communicate Topic 6 Networking Ch 2 Very large collection of smaller networks T C P I P 13 of 32 15 of 32 Transmission Control Protocol Internet Protocol TCP IP Two different protocols TCP IP TCP IP has become standard terminology to refer to either or both TCP Breaks messages into packets and reassembles them at their destination Takes care of transmission errors Remember packets Data is transmitted over shared communication lines Messages are divided into fixed sized numbered pieces these pieces are called packets 18 of 32 Topic 6 Networking Ch 2 3 Internet Protocol IP Routes packets through various networks T C P I P 2 TCP IP allows for low level network communication Consists of many protocols and programs High level protocols based on TCP IP SMTP Simple Mail Transfer Protocol used for email FTP File Transfer Protocol used for file transfers between 2 systems Telnet used to log into a computer system from a remote computer you must have an account HTTP Hyper Text Transfer Protocol used for the exchange of WWW documents which are typically written using HTML 19 of 32 Topic 6 Networking Ch 2 http www macarthurplace com U R L …