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  1. 1. Computer Network <ul><li>A group of computers and other networking devices connected by a common method to share resources are knows as data or Computer Network. </li></ul><ul><li>Three basic components of a N/W are: </li></ul><ul><li>Hardware </li></ul><ul><li>Software </li></ul><ul><li>Protocols </li></ul>
  2. 2. C0mponents of N/W <ul><li>Hardware: The all physical components required to setup Network. </li></ul><ul><li>Software: A set of programs which control and manage the H/W, provides Interface to the end user & support to application S/W. </li></ul><ul><li>Protocols: A set of communication rules which help devices to interact with each other and sent and receive information. </li></ul>
  3. 3. Types of Networking Modals <ul><li>The networking modal defines how computers are connected on a N/W to fulfill the different roles to be performed by them. </li></ul><ul><li>They are two primary networking modals used to define this interaction known as: </li></ul><ul><li>Client/Server Modal & </li></ul><ul><li>Peer to Peer or (Workgroup) </li></ul>
  4. 4. Client/Server Modal <ul><li>On a C/S modal certain computers act as a server and rest as a clients. </li></ul><ul><li>A server is a machine running some specific applications or program and provides some sort of services to other computers. </li></ul><ul><li>For example: FS, PS, DC’s, DNS, DHCP & </li></ul><ul><li>Web Server etc. </li></ul><ul><li>In a C/S modal user’s database and all other security settings are stored on a central server known as Domain Controller (DC). </li></ul>
  5. 5. Client/Server Modal, continue… <ul><li>Users log on to the DC instead of logging on to the individual machines and DC provides authentication. </li></ul><ul><li>Provides flexibility to administrator to control access to entire N/W from a central location. </li></ul><ul><li>C/S modal is used in medium to large enterprise N/Ws. </li></ul><ul><li>All modern computer N/W’s are based on Client/Server modal. </li></ul>
  6. 6. Workgroup <ul><li>In a workgroup model there is no client- server relationship. </li></ul><ul><li>Each individual system maintains its own users database and other security settings. </li></ul><ul><li>Unlike C/S modal, Users log on to the local machine and each machine provides authentication to its own users only. </li></ul><ul><li>Used in very small N/W, usually limited to 15 to 20 computers. </li></ul><ul><li>Doesn’t provide kind of flexibility & scalability like C/S model. </li></ul>
  7. 7. Types of Networks <ul><li>Types of Networks and other terminology used to define different types of Networks. </li></ul><ul><li>Local Area Network, (LAN) </li></ul><ul><li>Wide Area Network, (WAN) </li></ul><ul><li>Metropolitan Area Network, (MAN) </li></ul><ul><li>Internet, Intranet & extranet. </li></ul><ul><li>Lets discuss them one by one. </li></ul>
  8. 8. Local Area Network <ul><li>A LAN is a group of computers and other N/wing devices connected together to share resources. </li></ul><ul><li>Located in relatively small area, such as within a room, building, campus or premises. </li></ul><ul><li>Devices used in LAN includes: PC’s, Hubs, Bridges, Switches, Routers, Firewall etc. </li></ul><ul><li>The protocols or standard used in a LAN includes Ethernet, Token Ring & FDDI. </li></ul>
  9. 9. Wide Area Network <ul><li>WAN spread across large geographic area. </li></ul><ul><li>Provides connectivity between two or more remote LAN’s. </li></ul><ul><li>Requires services of third party (Carrier). </li></ul><ul><li>Point to point connections </li></ul><ul><li>Slower data transmission speed compare to LAN. </li></ul>
  10. 10. Metropolitan Area Network <ul><li>MAN is hybrid N/W (combination) of LAN & WAN. </li></ul><ul><li>Like WAN connects two or more LAN’s within the same geographical area. </li></ul><ul><li>Generally confined within city. </li></ul><ul><li>Like WAN, requires services of third party (Carrier). </li></ul><ul><li>Can provide high transmission speed like LAN. </li></ul>
  11. 11. Internet & Intranet <ul><li>Internet: is a Network of Networks! </li></ul><ul><li>A Network to be called as Internet, any unknown external user or users are allowed to access the part of resources of the Network. </li></ul><ul><li>Intranet: An intranet is a private N/W. </li></ul><ul><li>It can be a collection of LAN, MAN & WAN. </li></ul><ul><li>Users access the resources from within the organization (locally). </li></ul>
  12. 12. Extranet <ul><li>Extranet is a extended intranet. </li></ul><ul><li>Some services are made available to known users or business partners. </li></ul><ul><li>They can access resources from outside the organization (remotely) like home or office. </li></ul><ul><li>In intranet users access the resources from within the organization while in a extranet some known users are allowed to access the recourses from the outside Network . </li></ul>
  13. 13. LAN Protocols/Standard <ul><li>Three major LAN protocols or Media Type Ethernet, Token Ring and FDDI can be use to setup your LAN. </li></ul><ul><li>Of the three Ethernet is most popular LAN technology and has the largest installation base throughout the world. </li></ul><ul><li>Token Ring and Fiber Distributed Data Interface (FDDI) are distant second and third. </li></ul>
  14. 14. Ethernet -- LAN <ul><li>Today’s most LAN’s are based on the Ethernet technology! </li></ul><ul><li>Why Ethernet is popular: </li></ul><ul><li>Scalable – 10Mbps, 100Mbps, 1Gbps </li></ul><ul><li>Easy to implement </li></ul><ul><li>Easy to troubleshoot </li></ul><ul><li>Open standard </li></ul>
  15. 15. Ethernet <ul><li>Ethernet & other LAN protocols function at the data link layer of the OSI RM. </li></ul><ul><li>There are two variants of Ethernet, IEEE’s and DIX implementation. </li></ul><ul><li>Ethernet was first developed by Digital, Intel & Xerox and known as DIX. </li></ul><ul><li>DIX’s Ethernet was proprietary and its current version is called Ethernet - II </li></ul>
  16. 16. Ethernet <ul><li>IEEE’s Ethernet is based on open standard. </li></ul><ul><li>It was developed by Institute of Electrical & Electronics Engineers (IEEE). </li></ul><ul><li>There is three essential components of Ethernet: </li></ul><ul><li>CSMA/CD </li></ul><ul><li>Frame Format </li></ul><ul><li>Transmission Media </li></ul>
  17. 17. CSMA/CD <ul><li>Ethernet uses the CSMA/CD mechanism to send & receive data in a shared environment. </li></ul><ul><li>Carrier Sense : In a ethernet N/W when any device wants to transmit data first it listen to the carrier weather the carrier is free or not and this phase is known as Carrier Sense . </li></ul><ul><li>NIC detects (sense) the frames in the wire (Carrier) by examining the voltage levels or light frequency on the wire </li></ul>
  18. 18. CSMA/CD………. <ul><li>Multiple Access: All the devices can sense the carrier simultaneously as Ethernet supports multiple access and this phase in known as Multiple Access . </li></ul><ul><li>In other words no device has priority over any other device. </li></ul><ul><li>Any device which finds the carrier free starts transmitting data otherwise they wait for some specific time and again sense the carrier. </li></ul>
  19. 19. CSMA/CD……… <ul><li>Collision Detection Phase: When any machine places frames (data) on the wire it examines the status of the wire. </li></ul><ul><li>If two NIC transmit frames at the same time, a collision occur. </li></ul><ul><li>If NIC’s sense collisions on the wire they send a Jam signal and all machines stop sending or receiving data, & this is C. Detection phase. </li></ul><ul><li>Thereafter machines wait for a small random period and again start sensing the carrier. </li></ul>
  20. 20. Transmission Media <ul><li>Transmission media are used to carry data. </li></ul><ul><li>It can be wired or wireless media, however wired media is a primary method for connecting networking devices in a LAN. </li></ul><ul><li>Three types of cables are most common: </li></ul><ul><li>Coaxial Cables </li></ul><ul><li>UTP/STP Cables & </li></ul><ul><li>Fiber Optic Cables. </li></ul>
  21. 21. Coaxial Cable <ul><li>Coaxial and UTP/STP cables are based on copper and carry data in electrical signals. </li></ul><ul><li>Coaxial cables earlier used in Bus Topology Network. </li></ul><ul><li>BNC connectors were used with coaxial cables to connect devices. </li></ul><ul><li>This type of N/W doesn’t exist today. </li></ul><ul><li>However, coaxial cables are still used by cable TV Network. </li></ul>
  22. 22. UTP Cables <ul><li>UTP cables comes in different grade known as Cat- 1 to 6. </li></ul><ul><li>The grades defines speed & length of the cable. The speed range from 10 Mbps to 1 Gbps, Max. length can be up to 500 M. </li></ul><ul><li>In most of the LAN cat-5 cables are used which support 10 – 100 mbps transmission speed. </li></ul><ul><li>Unshielded twisted pair cables (UTP) are most common medium (cable) used in LAN. </li></ul>
  23. 23. UTP Cables…… <ul><li>The cable has 8 wires arrange in 4 pairs. </li></ul><ul><li>Each pairs are twisted, twisting prevents signals on different wires from interfering with each other’s signals (called Cross Talk) </li></ul><ul><li>Only 2 pairs (4 wires) used, one pair for transmitting and one pair for receiving signals. </li></ul><ul><li>RJ-45 connectors are used to crimped the wires in to Registered Jack. </li></ul>
  24. 24. STP Cables <ul><li>Similar to UTP, but it has only two pairs of wires. </li></ul><ul><li>Provide additional shielding to each wires. </li></ul><ul><li>Additional shielding make it more resistance proof to the outside interference. </li></ul><ul><li>Mostly used in Token Ring Network. </li></ul><ul><li>Token Ring Network also use UTP cables. </li></ul>
  25. 25. Fiber Optic Cables <ul><li>Fiber optic cables uses Glass or fiber filament and carry signals in the form of light. </li></ul><ul><li>Complete resistant proof to the electro -magnetic interference compare to UTP/STP. </li></ul><ul><li>Subject to less attenuation (the tendency of the signals to get weaker as it travels across the wire) compare to copper cables. </li></ul><ul><li>Signals can travel to very long distance. </li></ul><ul><li>Straight Trip (ST) & Subscriber Connector (SC) are used with fiber cables. </li></ul>
  26. 26. Ethernet Cabling <ul><li>Straight-through cable </li></ul><ul><li>PC Switch or Hub </li></ul><ul><li>Router Switch or Hub </li></ul><ul><li>Crossover cable </li></ul><ul><li>Switch Switch </li></ul><ul><li>Hub Hub </li></ul><ul><li>PC PC </li></ul>
  27. 27. Ethernet Cabling <ul><li>Straight & Crossover connection </li></ul>STRAIGHT OW – OR GW – BL BW – GR BRW - BR CROSS GW – G OW – BL BLW- O BRW-BR
  28. 28. Frame Format <ul><li>The frame format defines how data is encap-sulated (package) when it travel from one machine to other. </li></ul><ul><li>All computers must use same type of frames while communicating with in the same N/W. </li></ul><ul><li>IEEE has divided its Ethernet frame into 2 parts knows as 802.2 (LLC) upper layer and 802.3 (MAC) sublayer. </li></ul>
  29. 29. Frame Format <ul><li>IEEE has divided its Ethernet frame into 2 parts knows as 802.2 (LLC) upper layer and 802.3 (MAC) sub layer. </li></ul><ul><li>MAC-802.3: Media Access Control defines MAC addressing and how frames are placed & transmitted across media. </li></ul><ul><li>LLC-802.2: Logical Link Control is responsible for Identifying which network layer has created data and for encapsulating them. </li></ul>
  30. 30. MAC Addressing <ul><li>The data link layer uses MAC address for communication. </li></ul><ul><li>MAC address is 48 bits in length and represented as a hexadecimal number. </li></ul><ul><li>The values used range from 0–9 and A–F. </li></ul><ul><li>The first six digit is assigned to manufacturer of the LAN card by IEEE & known as OUI. </li></ul><ul><li>The last six digits are used to uniquely represent the NIC within the OUI value. </li></ul>
  31. 31. MAC Addressing 24 bits 24 bits The combination of OUI & serial No. is a unique Number. OUI- Assigned by- IEEE Vendor Assigned 00-02-44 0C-AC-62
  32. 32. Types of communication <ul><li>Half Duplex: In half duplex mode only one machine can send or receive data at a time. </li></ul><ul><li>Full Duplex: In full duplex environment devices can send & receive data simultaneously. </li></ul><ul><li>Simplex: Simplex communication refers where you can receive the message but you can’t reply. </li></ul>
  33. 33. Types of Messages <ul><li>Unicast: A unicast message is intended for one to one communication. </li></ul><ul><li>Multicast : A multicast message represents a group of devices. </li></ul><ul><li>Broadcast: A broadcast message is intended for all devices. </li></ul>
  34. 34. Baseband Vs Broadband <ul><li>In Baseband N/W transmission media can carry one signal at a time to transmit data across media. UTP and Fiber optic cables are example of Baseband media. </li></ul><ul><li>Broadband uses a different technique to carry multiple signals across the wire simultaneously. Coaxial and optical fiber are example of broadband media. </li></ul>
  35. 35. Advantages of Router <ul><li>Routers provides connectivity between different N/W based on (logical) IP address. </li></ul><ul><li>By using logical addressing at layer-3 routers allows you to build hierarchical networks that scale to very large size! </li></ul><ul><li>They contain broadcasts and can be used to solve broadcast problems. </li></ul><ul><li>Routers allow to connect different media types together, such as Ethernet, Token Ring & FDDI. </li></ul>
  36. 36. Created & designed by Tarang Agarwal Thank You