Lecture 01 networking

Lecture 01 networking

• 1.
  Information Technology III Lecture 01– Types of networks
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  What is aNetwork?  A system of interconnected computers and computerized peripherals such as printers in order to facilitates information sharing among them is called computer network  Computers may connect to each other by either wired or wireless media
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  Classification of ComputerNetworks  Computer networks are on various factors  Geographical span  Inter-connectivity  Administration  Architecture
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  Geographical Span  Spannedacross your table, among Bluetooth enabled devices,. Ranging not more than few meters.  Spanned across a whole building, including intermediate devices to connect all floors.  Spanned across a whole city.  Spanned across multiple cities or provinces.  One network covering whole world.
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  McGraw-Hill Technology EducationCopyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. Personal Area Network (PAN)  It is smallest network which is very personal to a user.  This may include Bluetooth enabled devices or infra-red enabled devices.  It has connectivity range up to 10 meters.  It may include wireless computer keyboard and mouse, Bluetooth enabled headphones, wireless printers and TV remotes.
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  Local Area Network(LAN)  A computer network spanned inside a building and operated under single administrative system is generally termed as Local Area Network  It covers an organization’ offices, schools, colleges or universities  It provides sharing the resources between end users such as  Printers  file servers  Mail servers  scanners and  internet
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  Local Area Network(LAN)  It may contains local servers serving file storage and other locally shared applications.  It mostly operates on private IP addresses  It works under its own local domain and controlled centrally  Main technologies are Ethernet or Token-ring  Ethernet is most widely technology with Star topology  LAN can be wired, wireless, or in both forms at once.
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  Virtual LAN (VLAN) Virtual LAN is a solution to divide a single Broadcast domain into multiple Broadcast domains.  Host in one VLAN cannot speak to a host in another. By default, all hosts are placed into the same VLAN.
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  Metropolitan Area Network(MAN)  IT generally expands throughout a city such as cable TV network.  It can be in the form of Ethernet, Token-ring, ATM, or Fiber Distributed Data Interface (FDDI)  Metro Ethernet is a service which is provided by ISPs  For example, MAN can help an organization to connect all of its offices in a city.  Backbone of MAN is high-capacity and high-speed fiber optics
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  Wide Area Network(WAN)  Wide Area Network (WAN) covers a wide area which may span across provinces and even a whole country.  These networks provide connectivity to MANs and LANs.  Since they are equipped with very high speed backbone, WANs use very expensive network equipment.  WAN may use advanced technologies such as  Asynchronous Transfer Mode (ATM)  Frame Relay and  Synchronous Optical Network (SONET)
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  Storage Area Network(SAN)  It is a dedicated network that provides access to consolidated, block level data storage  SANs are used to enhance storage devices, such as  disk arrays  tape libraries  optical jukeboxes  Accessible to servers so the devices appear like locally attached devices to the operating system  A SAN has own network of storage devices  not accessible through the local area network (LAN) by other devices
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  Network Architecture  Dependingupon its architecture network can be various types such as  Client-Server  peer-to-peer or  hybrid  There can be one or more systems acting as Server. Other being Client, requests the Server to serve requests.  Server takes and processes request on behalf of Clients  A server computer can manage several clients simultaneously,  One client can be connected to several servers at a time, each providing a different set of services.
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  Peer to peer(P2P)  Two systems can be connected Point-to-Point, or in back-to-back fashion  They both reside at the same level and called peers.  Peers share resources amongst each other  No use of a centralized administrative system
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  Internetwork  A networkof networks is called an internetwork, or simply the internet  The internet connects all WANs and it can have connection to LANs and Home networks  Internet uses TCP/IP protocol suite and uses IP as its addressing protocol  It uses WWW, FTP, email services, audio and video streaming etc  Internet works on Client-Server model  Internet uses very high speed backbone of fiber optics
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  Intranet  An intranetis a network based on TCP/IP protocols (an internet) belonging to an organization, usually a corporation  Accessible only by the organization's members, employees, or others with authorization.  An intranet's firewall blocks unauthorized access
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  Extranet  An extranetis a private network uses Internet technology and the public telecommunication system  It securely share business's information or operations with suppliers, vendors, partners, customers, or other businesses  An extranet can be viewed as part of a company's intranet that is extended to users outside the company
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  VPN – virtualprivate network  It is a network is constructed using the Internet to connect private network  such as a company's internal network  only authorized users can access the network and data cannot be intercepted  It is provides a secure, encrypted tunnel to transmit data between remote user and company network