Download pdf - EP 301 – Computer Networking Fundamentals

7/31/2019 EP 301 Computer Networking Fundamentals

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Shazul Afizi Bin Zulkiflee

14DTK10F1004

EP 301 Computer Networking

Fundamentals


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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

packets.

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.


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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.


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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.


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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.


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http://cablemodemss.com/wp-content/uploads/2011/06/Network-Bridge-Diagram.jpg


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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.


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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.


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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.


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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.


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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

network.
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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

layers.


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Protocol Router Bridge Router (B router)

a hardware device that convertsbetween two different types of

transmissions, such as

asynchronous and synchronous

transmissions.

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

connection.communications

forbidden by the network policy


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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

network