WEEK 6 :NETWORK TOPOLOGY

ASSALAMUALAIKUM & SALAM  SATU MALAYSIA

Hai kekawan...bejumpe lg kite pada minggu ini...ok seperti yang dijanjikan...dibawah ni sy telah updatekn nota pada minggu ni...pada minggu ni sy telah mempelajari mengenai network topology...JOMMM KITE 

SAME2 BELAJARRR :)

          Network Topology

         is the study of the arrangement or mapping of the elements (links, nodes, etc.) of a network, especially the physical (real) and logical (virtual) interconnections between nodes

         Physical topology

         Any given node in the LAN will have one or more links to one or more other nodes in the network and the mapping of these links and nodes onto a graph results in a geometrical shape that determines the physical topology of the network

         Logical  Topology :

         the mapping of the flow of data between the nodes in the network determines the logical topology of the network

         We will discuss about logical topology later

         Types/Classification of physical topologies

        § Linear Bus

        § Star

        § Star-Wired Ring

        § Tree

       TYPES OF PHYSICAL TOPOLOGY:

linear bus

         A linear bus topology consists of a main run of cable with a terminator at each end.

         All nodes (file server, workstations, and peripherals) are connected to the linear cable.

         Ethernet and LocalTalk networks use a linear bus topology.

         TYPES OF PHYSICAL TOPOLOGY:

Linear Bus

Topologi "linear bus" terdiri daripada suatu kabel utama dengan suatu penamat (terminator) dikedua-dua hujungnya.

         Semua nod (seperti komputer pelayan, stesyen kerja dan peranti lain) disambung kepada kabel linear ini.

         Contoh rangkaian yang menggunakan topologi Linear Bus ini ialah Ethernet dan LocalTalk.

       TYPES OF PHYSICAL TOPOLOGY:

LINEAR BUS

LINEAR BUS

                                                                           

         Advantages of a Linear Bus Topology

         Easy to connect a computer or peripheral to a linear bus.

         Requires less cable length than a star topology.

     Disadvantages

·         Entire network shuts down if there is a break in the main cable.

·         A faulty cable or workstation will take the entire LAN down

·         Terminators are required at both ends of the backbone cable.

·         Difficult to identify the problem if the entire network shuts down.

·         Not meant to be used as a stand-alone solution in a large building.

         TYPES OF PHYSICAL TOPOLOGY:

Star

-     A star topology is designed with each node (file server, workstations, and peripherals) connected directly to a central network hub or concentrator.

-     Data on a star network passes through the hub or concentrator before continue to its destination. The hub or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow.

         This configuration is common with twisted pair cable; however, it can also be used with coaxial cable or fiber optic cable.

         The protocols used with star configurations are usually Ethernet or LocalTalk

STAR

     Advantages

•         Easy to install, and wire.
• 
  
• ·         Easy to add new workstations
• 
  
• ·         No disruptions to the network when connecting or removing devices.
• 
  
• ·         Any non- centralised failure will have very little effect on the network
• 
  
• ·         Easy to detect faults and to remove parts.
• 
  
• ·         Centralized control
• 
  
• ·         Centralized network/hub monitoring

     Disadvantages

• ·         Requires more cable length than a linear topology.
• 
  
• ·         If the hub or concentrator fails, nodes attached are disabled.
• 
  
• ·         More expensive than linear bus topologies because of the cost of the concentrators.

         TYPES OF PHYSICAL TOPOLOGY:

Star-Wired

         A star-wired topology may appear (externally) to be the same as a star topology.

         Internally, the MAU (multistation access unit) of a star-wired ring contains wiring that allows information to pass from one device to another in a circle or ring

         The Token Ring protocol uses a star-wired topology.

         TYPES OF PHYSICAL TOPOLOGY:

Tree

         A tree topology combines characteristics of linear bus and star topologies.

         It consists of groups of star-configured workstations connected to a linear bus backbone cable. Tree topologies allow for the expansion of an existing network, and enable schools to configure a network to meet their needs

TREE

     Advantage

Point-to-point wiring for individual segments

     Disadvantages

• ·         Overall length of each segment is limited by the type of cabling used.
• 
  
• ·         If the backbone line breaks, the entire segment goes down.
• 
  
• ·         More difficult to configure and wire than other topologies.
• 
  

      SEMOGA SEMUA FAHAMM ..... :)

         <3 U ALL ....!!!!

WEEK 5 : COMPUTER NETWORKING

Assalamualaikum dan salam sejahtera..
HAI KEKAWAN,
Pada minggu kelima ni , sy telah mempelajari tentang   "computer networking".
bagi sesiapa yang ingin mengetahui lebih lanjut bolehlah baca sy punyer nOTA kt bawahh ini.
2 pun kalau korang paham la...hahahahahaha :)

What is computer networking??

haaaaa mesti xthu kn...heheheh ok meh sini sy terangkan...

Computer networking is connecting a computer with other devices to enable them to communicate with each other such as

• computer devices/ equipments
• transmission media to send/control data/signals
• communication devices to transmit/send data from sources to destinations
• software

Seterusnya pasal jenis2 network yang kite gune hari2 tuk daptkan maklumat..arr ade sesetengahh 2 pandai on9 je kn..tpi xthu...jadi tolangla bace kt bawh ni ye..baru la lebih afdoll  :)

Types of networks based on physical scope

Common types of computer networks may be identified by their scale. 

LAN - Local Area Network 

is a network that connects computers and devices in a limited geographical area such as home, school, computer laboratory, office building, or closely positioned group of buildings. Each computer or device on the network is a node.  


 

WAN - Wide Area Network

is a computer network that covers a large geographic area such as a city, country, or spans even intercontinental distances, using a communications channel that combines many types of media such as telephone lines, cables, and air waves. A WAN often uses transmission facilities provided by common carriers, such as telephone companies.  

PAN - Personal Area Network

 is a computer network used for communication among computer and different information technological devices close to one person. Some examples of devices that are used in a PAN are personal computers, printers, fax machines, telephones, PDAs, scanners, and even video game consoles. A PAN may include wired and wireless devices.  

 

MAN - Metropolitan Area Network

Lastly, tuk minggu ni sy belajar pasal komponen rangkaian atau " network component". HOPE KORANG BOLE PAHAM LA YEE...:)

Network components can be categories into 5. There are terminals, transmission media, network electronics, software and network architecture standards. 

1. Terminals & workstation: Normally refers to data sources and destinations. Example: Personal computers, terminals, workstations, computers, Automatic teller machines (ATM) 

2. Transmission media: The physical media used to transmit data in a networked environment. It is also use to transmit signal and electrical pulse through a medium. 2 types of transmission media are bounded/guided and unbounded/unguided. Examples of bounded media are twisted pair wire, coaxial cable and fiber optic cables. Examples of unbounded are AM & FM radio, TV broadcasting, satellite communication, microwave radio, infrared signals 

3. Network electronic devices are devices that control data transmission from sources to destinations. It also act as interface between different transmission media or communication protocol. For examples: Bridges, concentrators, routers, Front End Processors, Private Branch, Switches Exchange (PBX), Hubs, Multiplexers, and Gateways. 

4. Software: At the nodes, it involves techniques and protocols. Functions of the software are measure the data transmits to the destination. 

5. Network architecture standards: Architecture is blueprint of standards for a network consisting of items such as choice of media, media interfaces, encoding methods, transmission protocols, routing protocols and so on. It is needed to ensure interoperability between various devices and equipment made by different vendors. 

More information:

BASIC HARDWARE COMPONENT

All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers. In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable (most commonly Category 5 cable).  

BRIDGE
A Bridge does just what you would expect it to do - it joins two networks together so as far as data packets are concerned it looks like one large network


 

A bridge is not as capable as a Router - but it is less expensive.


HUB The network 'Hub' allows computers to share data packets within a network.

Each computer will be connected to a single 'port' on the hub. So if you purchase an '8 port hub', you will be able to connect up to eight computers together.
You can also 'daisy chain' hubs to allow even more computers to join the network.
However there is a problem with doing this - see 'Switches' for more details.

Typical network making use of a hub:


SWITCHES A switch has a number of ports and it stores the addresses of all devices that are directly or indirectly connected to it on each port.
As a data packet comes into the switch, its destination address is examined and a direct connection is made between the two machines.

PROTOCOL A 'protocol' is a rather technical word. But it simply means an agreed method of doing something.
A 'NETWORK PROTOCOL' is the agreed method of communication to be used within the network.
Each device / computer will use this protocol.

ENDNOTES

Within a vast computer network, the individual computers on the periphery of the network, those that do not also connect other networks, and those that often connect transiently to one or more clouds are called end nodes. Typically, within the cloud computing construct, the individual user / customer computer that connects into one well-managed cloud is called an end node. Since these computers are a part of the network yet unmanaged by the cloud's host, they present significant risks to the entire cloud. This is called the End Node Problem. There are several means to remedy this problem but all require instilling trust in the end node computer.

GATEWAY if your computer does not use the AOL protocol (and the chances are it won't). Then how do you get email to your friend on the AOL network?
Answer: A gateway.






A gateway converts the data passing between dissimilar networks so that each side can communicate with each other. i.e converts data into the correct network protocol.
The gateway is a mixture of hardware components and software.
This is unlike a standard 'Bridge' which simply joins two networks together that share the same protocol.

ROUTERS A Router is a device that transfers data from one network to another in an intelligent way. It has the task of forwarding data packets to their destination by the most efficient route.

In order to do this, the router has a micro computer inside it. This holds a table in memory that contains a list of all the networks it is connected to, along with the latest information on how busy each path in the network is, at that moment. This is called the 'routing table'

BLUETOOTH Bluetooth is a proprietary open wireless technology standard for exchanging data over short distances (using short-wavelength radio transmissions in the ISM band from 2400–2480 MHz) from fixed and mobile devices, creating personal area networks (PANs) with high levels of security. It can connect several devices, overcoming problems of synchronization. The devices can switch roles, by agreement, and the slave can become the master. At any given time, data can be transferred between the master and one other device.

IN-FRARED

This is a very familiar method of transferring data if you are at all aware of your remote control ! The television remote control makes use of an infra-red link. Personal organisers often make use of an infra-red link to synchronise calendars and 'to-do' lists.

OK TUK MINGGU NI, SAMPAI SINI JELA YANG SY DAPT KONGSIKAN..T MINGGU DEPAN Y LAEN PULOKK...SABARR YE TUNGGU TUK MINGGU DEPAN...:)

WEEK 4 : DATA COMMUNICATION

ASSALAMUALAIKUM....

HAIII.....OPSSS..LUPE PULOKK...BISMILAHIRAHMANIRAHIM..BERSYUKUR KEHADRAT ILLAHI KERANA MINGGU NI DAPT LG SY UPDATE BLOG SY Yg CNTIK LG MENARIK NI...:)  MENARIK KE??? harapan cm gthu la ye...

Ok MINGGU NI SY dapat menambah pengetahuan sy lg mengenai DATA COMMUNICATION...korang nk thu x data communication ni APE???

NK THU JOMMM layan DUNIA BELAJAR SY NI...:)

TPI TETAP SAME LA KN...IN ENGLISHHH....

HEHEHE....

DATA COMMUNICATION NI TERDIRI DARIPADA :

TYPES OF SIGNAL

-variety style : TEXT, PICTURE. etc

ANALOG SIGNAL :

Analog signals are signals with continuous values. Analog signals are used in many systems, although the use of analog signals has declined with the advent of cheap digital signals.

Analog systems are less tolerant to noise, make good use of bandwidth, and are easy to manipulate mathematically. However, analog signals require hardware receivers and transmitters that are designed to perfectly fit the particular transmission. If you are working on a new system, and you decide to change your analog signal, you need to completely change your transmitters and receivers.

 

DIGITAL SIGNAL :

Digital signals are signals that are represented by binary numbers, "1" or "0". The 1 and 0 values can correspond to different discrete voltage values, and any signal that doesnt quite fit into the scheme just gets rounded off.

Digital signals are sampled, quantized & encoded version of continuous time signals which they represent. In addition, some techniques also make the signal undergo encryption to make the system more tolerent to the channel.

DATA FLOW

Simplex, half-duplex and full-duplex connections

There are 3 different transmission modes characterised according to the direction of the exchanges:

A simplex connection is a connection in which the data flows in only one direction, from the transmitter to the receiver. This type of connection is useful if the data do not need to flow in both directions (for example, from your computer to the printer or from the mouse to your computer...).

A half-duplex connection (sometimes called an alternating connection or semi-duplex) is a connection in which the data flows in one direction or the other, but not both at the same time. With this type of connection, each end of the connection transmits in turn. This type of connection makes it possible to have bidirectional communications using the full capacity of the line.

A full-duplex connection is a connection in which the data flow in both directions simultaneously. Each end of the line can thus transmit and receive at the same time, which means that the bandwidth is divided in two for each direction of data transmission if the same transmission medium is used for both directions of transmission.

DATA TRANSMISSION MODES

Serial connection

In a serial connection, the data are sent one bit at a time over the transmission channel. However, since most processors process data in parallel, the transmitter needs to transform incoming parallel data into serial data and the receiver needs to do the opposite.

These operations are performed by a communications controller (normally a UART (Universal Asynchronous Receiver Transmitter) chip). The communications controller works in the following manner:

The parallel-serial transformation is performed using a shift register. The shift register, working together with a clock, will shift the register (containing all of the data presented in parallel) by one position to the left, and then transmit the most significant bit (the leftmost one) and so on:

The serial-parallel transformation is done in almost the same way using a shift register. The shift register shifts the register by one position to the left each time a bit is received, and then transmits the entire register in parallel when it is full.

MODES OF TRANSMITTING DATA

Synchronous Transmission:

 Large volumes of information can be transmitted at a single time with synchronous transmission. This type of transmission involves the simultaneous flow of several bytes of data. Because a large block of data being sent synchronously cannot be interrupted, a synchronized clock is necessary to carefully schedule the transmission of information. This special communications equipment is expensive; but this cost can be made up in part by faster, less expensive transmission of information.

Asynchronous Transmission: 

Conversely, asynchronous transmission involves the sending and receiving of one byte of data at a time. This type of transmission is most often used by microcomputers and other systems characterized by slow speeds.

OK NI JE YANG DAPAT SAYA KONGSI NGAN KORANG SUME TUK MINGGU NI...ENJOYY HARY MINGGU KORANGGG K ...PEACE YOOO  :)