DITEC - Fundamentals in Networking

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Diploma in Information TechnologyModule IV: Fundamentals in NetworkingBy: Rasan SamarasingheEsoft Computer Studies (pvt) Ltd.No 68/1, First Floor, Main Street, Pallegama, Embilipitiya.

ContentWhat is a computer network?Types of computer networksPersonal Area Network Local Area Network Metropolitan Area NetworkWide Area Network Networking TopologiesPhysical TopologiesPhysical point to point Physical bus topologyPhysical ring topologyPhysical star topologyPhysical mesh topologyPhysical hybrid topologyLogical Topologies

Logical bus topologyLogical ring topologySwitching implementedNetworking CablesCoaxial CablesTwisted Pair CablesFiber Optic CablesNetworking DevicesNIC-Network interface cardHubNetwork SwitchRouterBridgeIP AddressActivities

What is a computer network?Computer network is an interconnection of two or more computers and other devices. Devices on a network can be linked by cables, telephone lines, radio waves or infrared waves.

Advantages of computer networksFiles sharingDevices sharingCommunication Services sharing

Disadvantages of computer networksVirus attacksHacker attacksFailures of a server may effect to the entire network

Types of computer networksBased on the network size, networks can be categorized into several types

Personal Area Network (PAN)Local Area Network (LAN)Metropolitan Area Network (MAN)Wide Area Network (WAN)

Personal Area Network (PAN)PAN is wireless network connected with mobile devices such as mobile phones, PDAs, Bluetooth printers, Headsets, etc. The technology using in here is Bluetooth or infrared.

Local Area Network (LAN)Coverage is about within 1km. Ex: a company network within a building or may be within two or more buildings

Metropolitan Area Network (MAN)Coverage is about more than 1km and less than 10km.Ex: A network of a large town

Wide Area Network (WAN)Coverage is about more than 10km.Satellites may be use to expand this network.Ex: Internet

Networking TopologiesTopology is the way that we connect computers and other devices. In other words topology is the map of the network

Networking TopologiesTopologies can be divided into two sections

Physical TopologiesLogical Topologies

Physical TopologiesPhysical arrangement of the network is known as physical topology

Ex:Physical point to point topologyPhysical bus topologyPhysical ring topologyPhysical star topologyPhysical mesh topologyPhysical hybrid topology

Physical Point to Point TopologyThis is the simplest topology that uses a permanent link between two end devices. It also known as peer to peer topology.

Physical Point to Point TopologyCharacteristicsUsing twisted pair cablesRJ-45 connectorsMaximum segment length is 100m

Physical Point to Point TopologyAdvantagesLow costNo additional devices or servers neededEasy to implement

Physical Point to Point TopologyDisadvantagesMaximum 2 computers can be connectedCable breaks will effect to the whole network

Physical Bus TopologyEach computers and devices are connected to a single cable called backbone.

Physical Bus TopologyCharacteristicsChannel accessing method is CSMA/CD (carrier sense multiple access / collision detection)Both thin net and thick net coaxial cables are usedSegment length of thin net coaxial cable is 200mSegment length of thick net coaxial cable is 500mBNC Connectors are usedMaximum data transfer speed is 10mbps

Physical Bus TopologyAdvantagesEasy to implementEasy to expandLow cost (no additional devices)

Physical Bus TopologyDisadvantagesMaximum speed is 10mbps onlyNumber of PCs will effect to the performance of the networkIf backbone breaks, the entire network will downNot suitable for heavy trafficHard to find faults of the network

Physical Ring TopologyEach computers and devices are connected each other forming a large circle.

Physical Ring TopologyCharacteristicsChannel accessing method is Token PassingUsing coaxial or twisted pair cablesConnectors used BNC or RJ-45Maximum data transfer speed is between 4 -16mbps

Physical Ring TopologyAdvantagesNo collisions are occurredNo need of a serverEven the load of the network increases, it still perform better than bus topology.

Physical Ring TopologyDisadvantagesIf the cable breaks, entire network will be downIf one station goes down, it will be affected to the entire network.Low speed

Physical Star TopologyAll the components of the network are connected to the central device called hub or switch

Physical Star TopologyCharacteristicsTwisted pair cables are usingConnectors are RJ-45Channel accessing method is depends on the central device

Physical Star TopologyAdvantagesHigher data transfer speed than previous topologies. 100 1000mbpsCentral device make it easy to manage the networkCable breaks will not effect to the entire networkEasy to expandCan connect more computers and devices

Physical Star TopologyDisadvantagesSingle point of failure type networkThe central device using is increases the cost of the network

Extended Star Topology

Extended StarTree

Physical Mesh TopologyEach networking node are interconnected with each other

Physical Mesh TopologyCharacteristicsIt allowing most transmissions to be distributed, even one of the connections goes downUses in the internet

Physical Mesh TopologyAdvantagesCan use for high trafficCable breaks will not effect to the communicationExpansions and modifications can be done without disrupting other devices

Physical Mesh TopologyDisadvantagesOverall cost of the network is highSetup, maintaining and administrating this network is very tough

Physical Hybrid TopologyThe combination of more topologies is known as hybrid topology

Physical Hybrid TopologyAdvantagesFlexible to expand and modifyVery effective

DisadvantagesVery complexCostly infrastructure

Logical TopologiesLogical topology represents the way that data travel through the computer

Ex:Logical bus topologyLogical ring topologySwitching implemented as physical star

Logical Bus TopologyIn here, the central device called hub works as data packet distributer similar in action of the bus topology

Hub

Logical Bus TopologyCharacteristicsChannel accessing method is CSMA/CDCable using is twisted pairConnector using is RJ-45Data transfer speed is 10mbpsCable breaks will not effect to the entire networkSingle point of failure type network

Logical Ring TopologyThe central device called MSAU acts very similar to the ring architecture when data packets are travelling.

MSAU

Logical Ring TopologyCharacteristicsChannel accessing method is token passingCable type is twisted pairConnectors are RJ-45Maximum data transferring speed is 16mbpsCable breaks will not affect to the entire networkNo collisions occurredSingle point of failure type network

Switching implemented as physical starThe central device using is networking switch. It receives data packets from end devices and forwarding them towards the particular destination device or computer.

Switch

Switching implemented as physical starCharacteristicsChannel accessing method is switchingMaximum data transferring speed is 100-1000mbpsUsing twisted pair cablesUsing RJ-45 connectorsCable breaks will not effect to the whole networkSingle point of failure type network

Networking CablesThere are several kind of networking cables

Coaxial CablesTwisted Pair CablesFiber Optic Cables

Coaxial CablesCoaxial cables are two typesThin net coaxial cablesThick net coaxial cables

Outer coverOuter copper shieldInner insulatorInner inductor

Thin net coaxial cablesUse to connect computers and devices in bus topology and ring topologyWell flexibleMaximum segment length is 200m (185m)

Thick net coaxial cablesUsed as backbone cables and outdoor layingNot well flexibleMaximum segment length is 500m (485m)

Coaxial cable connectors

BNC Connectors

Twister Pair CablesMost popular network cable in networkingThere are two types called:Unshielded twisted pair cablesShielded twisted pair cablesMaximum segment length is 100mData transferring speed varied on cable categories

Unshielded Twister Pair Cables (UTP)

Shielded Twister Pair Cables (STP)

Twisted pair cable categoriesCategorySpeedCAT 1Voice gradeCAT 24 MbpsCAT 316MbpsCAT 4100MbpsCAT 51000MbpsCAT 5e1000MbpsCAT 61000MbpsCAT 71000Mbps

Twisted pair cable connectors

RJ-45 ConnectorsRJ-45 Base

Twisted Pair / RJ-45 Cabling Types

Fiber Optic CablesFiber optic cables uses light pulses to send and receive data.Have very higher data transfer speed. Ex: 10Gbps or 100GbpsThere are two types of fiber optic cables mainlySingle Mode Fiber (SMF)Multi Mode Fiber (MMF)

Single Mode Fiber Optic CablesTransmit one light pulse at a time for one directionBecause of this reason devices need two cables for full duplex communication

Multi Mode Fiber Optic CablesTransmit more than one light pulseBecause of that full duplex communication can achieve using a single cableThese cables are not suitable for long distance data transfer

Undersea Cable Map

Fiber Optic Media Converters

Fiber Optic Connectors

Networking DevicesNIC-Network interface cardHubNetwork SwitchRouterBridge

Network Interface Card (NIC)

Network Interface Card (NIC)Every computer should have a network interface card to connect to the networkThere are several things to consider before buying a NICNetwork interface (connectors)Internal interface (PCI, USB)Network architecture

Hub

HubHub is use to connect all computers and other devices togetherHub is a broadcasting deviceMaximum data transfer speed is 10MbpsThere are two types of hubs:Active HubsPassive Hubs

Active HubsWhen active hubs receive a signal in one port, it boost the signal and remove the electromagnetic noises before send that to other devices.

Passive HubsIn passive hubs, it do not amplify the signal or remove noise before send data to other computers

Network SwitchSwitches are also use to connect computers in physical star topology and these devices are intelligent than hubs.

How network switch works?Switches maintain a small table in there RAM to identify computers that related with the port numbers.When switch receives a data packet, it reads the packet header to identify destination address.After that it will search the entire table to find the related port for that address.Then it can directly forward that data packet to the related computer rather than broadcasting.

Network Switch TypesLayer 2 switches (unmanaged switches)Using MAC addresses of connected devices.

Layer 3 switches (managed switches)Using IP addresses of connected devices.Providing more features than layer 2 switches and expensive.

Routers

RoutersRouters are use to connect networks together.Routers are more intelligent devices and it use IP addresses to deal with the packet.Routers are responsible for:Identify proper networks and sub networks.Forward data packets using the best path.Destroying TTL data packets. Etc

BridgeBridge can use to connect different topologies together or can use to connect different cable types together.

IP Address (Internet Protocol)IP address is an unique address that use to identify computers and devices.There are two IP versions called IPv4 and IPv6IPv4 is the common version that used in most networks.IPv4 is made up with 4 decimal numbers and each are separated by dots. (###.###.###.###) and each number can be in between 0 to 255.IP versions, rules and regulations are created and maintain by IANA (Internet Assigned Number Authority)

IP Classes (IPv4)Class AClass BClass CClass D (reserved for multicasting purposes)Class E (reserved for experimental purposes)

Can use in our networks

IP AddressIP Addresses are made up with two sectionsNetwork Address (network portion)Host Address (host portion)NHHH

NNHH

NNNH

NNNH

NNNH

Class AClass BClass CClass DClass E

IP Ranges in each classesIP ClassFirst OctateIP AddressReceived BitsRange (min-max)Class A0#######00000000-01111111(1-126)1-1260-2550-2550-255Class B10######10000000-10111111(128-191)128-1910-2550-2550-255Class C110#####11000000-11011111(192-223)192-2230-2550-2550-255Class D1110####11100000-11101111(224-239)224-2390-2550-2550-255Class E1111#####11110000-11111111(240-255)240-2550-2550-2550-255

ActivitiesAssigning IP address to connect two computersSharing FilesSharing Printer

The Endhttp://twitter.com/rasansmn