EP 301 – Computer Networking Fundamentals

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  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Shazul Afizi Bin Zulkiflee


    EP 301 Computer Networking


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    HUB A common connection point for devices in a network. Hubs are

    commonly used to connect segments of a LAN. A hub contains

    multiple ports. When a packet arrives at one port, it is copied to

    the other ports so that all segments of the LAN can see all


    A passive hub serves simply as a conduit for the data, enabling itto go from one device (or segment) to another. So-called

    intelligent hubs include additional features that enables an

    administrator to monitor the traffic passing through the hub and

    to configure each port in the hub. Intelligent hubs are also called

    manageable hubs.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Switch A network switch or switching hub is a computer networking

    device that connects network segments or network devices. Theterm commonly refers to a multi-port network bridge thatprocesses and routes data at the data link layer (layer 2) of theOSI model. Switches that additionally process data at thenetwork layer (layer 3) and above are often referred to as layer-3

    switches or multilayer switches.

    Network switches appear nearly identical to network hubs, but aswitch generally contains more intelligence (and a slightly higherprice tag) than a hub. Unlike hubs, network switches are capableof inspecting data packets as they are received, determining the

    source and destination device of each packet, and forwardingthem appropriately. By delivering messages only to theconnected device intended, a network switch conserves networkbandwidth and offers generally better performance than a hub.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Repeater and Bridge

    Repeater Repeaters regenerate incoming electrical, wireless or optical

    signals. With physical media like Ethernet or Wi-Fi, data

    transmissions can only span a limited distance before the

    quality of the signal degrades. Repeaters attempt to preserve

    signal integrity and extend the distance over which data can

    safely travel.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Bridge A bridge device filters data traffic at a network boundary. Bridges

    reduce the amount of traffic on a LAN by dividing it into twosegments.

    Bridges operate at the data link layer (Layer 2) of the OSI model.

    Bridges inspect incoming traffic and decide whether to forward ordiscard it. An Ethernet bridge, for example, inspects eachincoming Ethernet frame - including the source and destinationMAC addresses, and sometimes the frame size - in makingindividual forwarding decisions.

    Bridges serve a similar function as switches, that also operate at

    Layer 2. Traditional bridges, though, support one networkboundary, whereas switches usually offer four or more hardwareports. Switches are sometimes called "multi-port bridges" for thisreason.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Difference Hub and Switch Hub

    A hub is the simplest of these devices. Any data packetcoming from one port is sent to all other ports. It is thenup to the receiving computer to decide if the packet is forit. Imagine packets going through a hub as messages

    going into a mailing list. The mail is sent out to everyoneand it is up to the receiving party to decide if it is ofinterest.The biggest problem with hubs is their simplicity.Since every packet is sent out to every computer on thenetwork, there is a lot of wasted transmission. This

    means that the network can easily become boggeddown.Hubs are typically used on small networks wherethe amount of data going across the network is neververy high.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Switch A switch steps up on a bridge in that it has multiple ports.

    When a packet comes through a switch it is read to determine

    which computer to send the data to.This leads to increased

    efficiency in that packets are not going to computers that do

    not require them.Now the email analogy has multiple people

    able to send email to multiple users. The switch can decide

    where to send the mail based on the address.Most large

    networks use switches rather than hubs to connect computers

    within the same subnet.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Difference Repeater and

    Bridge Repeater

    Forwards every frame it receivesit is a generator,not an amplifier(i.e it removes noise &regenerates signal )Bi-directional in natureUseful in increasing ethernet size/lengthMaximum of 5 Repeaters in an Ethernet.

    Bridge Connect similar/dissimilar LANS

    Designed to store and forward frameProtocol independent

    Transparent to End StationsOperates in Layer-1 & Layer-2uses a table for filtering/routingdoes not change the Mac address in the frametwo types of bridges are there Transparent/source routine.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    15 Networking Devices

    Router Hub

    a specialized network device that

    determines the next network point

    to which it can forward a data

    packet towards the destination ofthe packet. Unlike a gateway, it

    cannot interface different protocols.

    Works on OSI layer 3.

    connects multiple Ethernet

    segments together making them act

    as a single segment. When using a

    hub, every attached all the objects,compared to switches, which

    provide a dedicated connection

    between individual nodes. Works on

    OSI layer 1.

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Bridge Switch

    a device that connects multiplenetwork segments along the data

    link layer. Works on OSI layer 2.

    a device that allocates trafficfrom one network segment to

    certain lines (intended

    destination(s)) which connect

    the segment to another

    network segment. So unlike a

    hub a switch splits the

    network traffic and sends it to

    different destinations rather

    than to all systems on the


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Repeater Multilayer switch

    device to amplify or regeneratedigital signals received while

    sending them from one part of a

    network into another.

    a switch which, in addition toswitching on OSI layer 2, provides

    functionality at higher protocol


  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Protocol Router Bridge Router (B router)

    a hardware device that convertsbetween two different types of

    transmissions, such as

    asynchronous and synchronous


    CombineS router and bridgefunctionality and are therefore

    working on OSI layers 2 and 3.

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    Digital Subscriber LineAccess Multiplexer

    Integrated AccessDevice

    (DSLAM, often pronounced dee-slam) allows telephone lines to

    make faster connections to the

    Internet. It is a network device,

    located in the telephone exchanges

    of the internet service providers,

    that connects multiple customer

    Digital Subscriber Lines (DSLs) to ahigh-speed Internet backbone line

    using multiplexing techniques

    a customer premise device thatprovides access to wide area

    networks and the Internet.

    Specifically, it aggregates multiple

    channels of information including

    voice and data across a single

    shared access link to a carrier or

    service provider PoP (Point ofPresence). The access link may be

    a T1 line, a DSL connection, a cable

    (CATV) network, a broadband

    wireless link, or a metro-Ethernet


    forbidden by the network policy

  • 7/31/2019 EP 301 Computer Networking Fundamentals


    Network AddressTranslator Multiplexer

    network service provide ashardware or software that converts

    internal to external network

    addresses and vice versa

    device that combines severalelectrical signals into a single signal

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    Network Card Modem

    a piece of computer hardware toallow the attached computer to

    communicate by network

    device that modulates ananalog "carrier" signal (such as

    sound), to encode digital

    information, and that also

    demodulates such a carrier

    signal to decode the transmitted

    information, as a computer

    communicating with another

    computer over the telephone