Pembelajaran 6 - Infrastruktur Internet

Assalamualaikum dan salam sejahtera

Pada kali ini, saya akan menerangkan beberapa kandungan asas yang diperoleh dalam kuliah tentang Infrastruktur Internet antaranya definisi internet, protokol internet dan jenis-jenis sambungan kepada internet. Moga bermanfaat. :)

Penerangan

- Internet merupakan rangkuman beberapa rangkaian besar dalam satu jaringan yang menghubungkan jutaan komputer/peranti secara global sekali gus mewujudkan komunikasi antara pengguna

- Peranti/komputer yang mempunyai komunikasi dan rangkaian antara satu sama lain memancarkan data melalui pensuisan paket khas yang dikenali sebagai Internet Protocol (IP)

- Apabila pengguna berjaya menyambungkan komputer/peranti dengan Internet, pengguna telah menjadi sebahagian daripada rangkaian

- World Wide Web (WWW) merupaan medium carian dan membolehkan pengguna melayari laman sesawang melalui sambungan komputer/peranti dengan internet

Susun Atur Sambungan Rangkaian

Peranti/komputer > Local Area Network (LAN) > Internet Service Provider ISP (eg: TM, Yes) > WWW

Pembekal Perkhidmatan Internet (ISP)

- Perkhidmatan ini diuruskan melalui organisasi/syarikat perkhidmatan telekomunikasi

- Kebiasaannya, syarikat ini menawarkan pelbagai pelan data internet sama ada bagi telefon bimbit atau langganan internet mudah alih yang turut dibekalkan Dongle dan Modem/Router

- ISP mempunyai rangkaian bersama Network Access Point (NAP)
- Contoh ISP: Maxis, Digi, Yes 4G

Internet Protocol (IP)

- Internet Protocol (IP) merupakan protokol/kaedah bagi komputer menghantar data kepada komputer lain melalui talian internet
- Setiap komputer mempunyai alamat/nombor IP tersendiri yang berbeza
- Alamat IP terdiri dalam bentuk binari

172 = Kawasan/lokasi rangkaian
16 = Nombor Server
254 = Nombor Unit
1 = Nombor komputer

Domain Name System (DNS)

- DNS ialah domain bagi internet diterjemahkan dalam bentuk IP 

- Perkhidmatan internet menterjemahkan domain seperti laman sesawang kepada protokol bernombor
- Penggunaan DNS adalah lebih mudah berbanding menggunakan nombor bagi pengguna melayari laman sesawang

Hyper Text Transfer Protocol (HTTP)

- HTTP merupakan satu set peraturan untuk pemindahan fail (sebarang bentuk fail multimedia) ke dalam laman sesawang
- Sebaik sahaja pengguna membuka pelayar laman sesawang yang bertindak sebagai klien, secara automatiknya pengguna akan menggunakan HTTP
- Apabila pengguna memasukkan carian dalam bentuk Uniform Resource Locator (URL), pelayar laman sesawang menterjemahkannya dalam bentuk HTTP dan menghantar kepada IP berdasarkan URL tersebut

Jenis - Jenis Sambungan Internet




1. Sambungan Panggilan (Dial Connection)

- Menggunakan modem konvensional yang bersambung dengan sambungan telefon rumah
- Sambungan ini memperlihatkan kelajuan internet yang rendah dan memerlukan tempoh yang lama untuk mendapat akses internet





2. Kabel

- Sambungan ini memerlukan sambungan kabel yang panjang bagi kegunaan pejabat dan memerlukan kos yang tinggi untuk dipasang

3. Akses Internet Satelit

- Akses ini berfungsi dengan membekalkan rangkaian secara terus ke satelit menggunakan antenna yang berbentuk piring
- Jenis sambungan ini biasanya dapat dilihat di kawasan pulau yang menggunakan kaedah ini berbanding sambungan kabel
- Akses ini mempunyai kelemahan seperti rangkaian yang terganggu akibat cuaca buruk





4. Rangkaian Tanpa Wayar Tetap


- Akses ini menggunakan tiang pemancar yang dipasangkan di kawasan tertentu untuk membekalkan jaringan
- Akses ini membekalkan kelajuan rangkaian yang lebih sekiranya pengguna berada berhampiran dengan tiang pemancar tersebut

5.  Broadband


- Merupakan satu kaedah penghantaran data melalui satu Access Point kepada peranti/komputer
- Dongle merupakan satu contoh alat yang membekalkan jaringan rangkaian apabila dipasangkan kepada komputer
- Kebanyakan syarikat telekomunikasi menawarkan pelbagai pakej plan internet melalui alat ini
- Kelajuan penghantaran data melalui alat ini melebihi sekitar 1.5Mbit/s dan mempunyai kelajuan frekuensi melebihi sekitar 1MHz

6. Rangkaian Tanpa Wayar Mudah Alih

- Akses rangkaian seperti ini adalah seperti yang digunakan pada telefon bimbit masa kini
-  Rangkaian telefon mudah alih telah berkembang dengan rancak bermula dari G (generasi pertama) hingga 4G (generasi keempat) yang digunakan meluas kini
- Contoh pembekal rangkaian ini ialah: Maxis, Digi, Celcom

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Pembelajaran 5 - Teknologi Tanpa Wayar

Assalamualaikum dan selamat sejahtera. 

Untuk minggu ini topik pembelajaran yang diterangkan oleh Dr Dayana ialah jenis-jenis teknologi tanpa wayar yang terdapat dalam era teknologi kini. Seperti biasa, sebelum saya menerangkan tentang beberapa jenis teknologi tersebut, mari kita lihat dahulu pengenalan dan kegunaan teknologi tanpa wayar ini kepada pengguna

Pengenalan dan Kegunaan

- Isyarat teknologi tanpa wayar dalam bentuk gelombang radio (radiowave) digunakan untuk menghantar data tanpa menggunakan sebarang kabel

- Hampir keseluruhan peranti masa kini menggunakan metadologi ini dalam mewujudkan rangkaian dan komunikasi seperti yang dapat dilihat dalam penggunaan komputer riba, telefon bimbit dan penggunaan Global Positioning System (GPS)

Jenis - Jenis Rangkaian Teknologi Tanpa Wayar

1. Infrared

- Maklumat dihantar melalui pancaran cahaya dalam jarak yang pendek

- Maklumat tidak dihantar melalui gelombang

- Teknologi ini kurang digunakan kini kerana perkembangan teknologi rangkaian lain seperti Bluetooth dan Near Field Communication (NFC)

- Penggunaan teknologi ini dapat dilihat melalui penggunaan alat kawalan televisyen

- Kelajuan penghantaran maklumat bagi teknologi ini adalah sekitar 2400 bps - 4 Mbps

2. Wireless Local Area Networks (WLAN)

- Teknologi ini dapat dilihat melalui penggunaan internet tanpa wayar (Wi-Fi)

- Rangkaian ini tertakluk pada piawaian IEEE 802.11

- Teknologi ini tidak memerlukan peranti untuk menyambungkan kabel ke Access Point (AP) untuk mendapatkan rangkaian

- Ia juga memudahkan pengguna untuk mendapatkan rangkaian tidak kira dimana kedudukan pengguna selagi kawasan yang diduduki pengguna mempunyai AP tersebut. 

Contoh Dongle 

3. Broadband

- Merupakan satu kaedah penghantaran data melalui satu Access Point kepada peranti/komputer

- Dongle merupakan satu contoh alat yang membekalkan jaringan rangkaian apabila dipasangkan kepada komputer

- Kebanyakan syarikat telekomunikasi menawarkan pelbagai pakej plan internet melalui alat ini

- Kelajuan penghantaran data melalui alat ini melebihi sekitar 1.5Mbit/s dan mempunyai kelajuan frekuensi melebihi sekitar 1MHz

4. Bluetooth

- Teknologi ini membolehkan komunikasi mudah alih antara 2 peranti dalam jarak yang dekat

- Berbeza dengan Infrared, teknologi Bluetooth tidak akan terganggu sekiranya berlaku halangan antara 2 peranti ketika berkomunikasi

- Kamera digital, pencetak, telfon bimbit dan komputer riba merupakan contoh peranti yang mempunyai teknologi ini pada masa kini.

- Jarak untuk membolehkan teknologi ini digunakan adalah tidak melebihi 30 kaki

5. WiMax

- Secara praktikalnya, WiMax berfungsi sama seperti teknologi yang digunakan Wi-Fi

- Namun demikian teknologi WiMax meliputi kawasan yang luas untuk membekalkan rangkaian kepada komputer/peranti

- Rangkaian ini sesuai untuk dibangunkan di kawasan yang belum membangun kerana dapat menjimatkan kos pemasangan/bekalan rangkaian yang berskala kecil dan memerlukan pemasangan kabel

- Bagi pengguna yang tinggal berhampiran dengan pencawang atau AP WiMax, kelajuan maksima rangkaian dapat diperoleh

6. Rangkaian Telefon Mudah Alih

- Rangkaian telefon mudah alih telah berkembang dengan rancak bermula dari G (generasi pertama) hingga 4G (generasi keempat) yang digunakan meluas kini

- Dalam generasi pertama, data dihantar dan diterima dalam bentuk analog

- Saiz peranti yang digunakan juga berskala besar dan berbentuk bata

- Rangkaian 2G memperlihatkan bagaimana data dapat diproses dalam bentuk digital seperti sistem pesanan ringkas (SMS), sistem pesanan multimedia (MMS), dan panggilan suara dibuat

- Bagi rangkaian 3G pula, ia membolehkan peranti bertindak sebagai komputer riba dimana rangkaian ini membolehkan pengguna melayari laman web, penggunaan GPS dan panggilan video namun dalam capaian yang perlahan dan boleh mengganggu kelancarannya

- Teknologi rangkaian 4G merupakan rangkaian paling pantas yang ada pada masa kini bagi pengguna telefon bimbit khususnya dengan penambahbaikan dari sudut kelajuan pemprosesan data

Berikut merupakan rangkuman kandungan kuliah pada minggu ini. Pada minggu hadapan, Dr Dayana akan memberi kuliah tentang Infrastruktur Internet. Terima kasih kerana sudi membaca dan meluangkan masa di blog ini. :)

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Lesson 4 - Cabling & Hardware

Assalamualaikum and greetings. :)

In today's update, I will share about cables and hardware needed to setup a network between computer/devices. But before that, lets take a look at simple explanation the 2 types of network.

1. Wired Network

Wired networks provide users with plenty of security and the ability to move lots of data very quickly. It is typically faster than wireless networks and they can be very affordable. However, the cost of Ethernet cable can add up more computers on your network and the farther apart they are. Thus, the more expensive your network will be. In addition, unless you're building a new house and installing Ethernet cable in the walls, you'll be able to see the cables running from place to place around your home, and wires can greatly limit your mobility. A laptop owner, for example, won't be able to move around easily if his computer is tethered to the wall.

2. Wireless Network (Wi-Fi)

The easiest and least expensive way to connect the computers in your home is to use a wireless network, which uses radio waves instead of wires. The absence of physical wires makes this kind of network very flexible. For example, you can move a laptop from room to room without fiddling with network cables and without losing your connection. The weakness is that wireless connections are generally slower than wired connections and they are less secure unless you take measures to protect your network

There are 3 types of cables that usually used to set up a network connections such as:

1. Coaxial

- Coaxial cables have concentric layers of electrical conductors and insulating material. It ensures that signals are enclosed within the cable and prevents electrical noise from interfering with the signal. It also yields the name "coaxial," referring to its two physical channels running along the same axis

- The center layer is a thin conducting wire, either solid or braided copper. A dielectric layer, made up of an insulating material with very well-defined electrical characteristics, surrounds the wire. A shield layer then surrounds the dielectric layer with metal foil or braided copper mesh. The whole assembly is wrapped in an insulating jacket. The outer metal shield layer of the coax cable is typically grounded in the connectors at both ends to shield the signals, and as a place for stray interference signals to dissipate

- Nowadays, these type of cable usually used to connect television and community antenna 

Bayonett-Neill-Concelman (BNC) connector

- The most common type of connector of this cable is Bayonett-Neill-Concelman (BNC) connector

2. Fibre Optic

- Fibre optic cable is based on optical fibres which are long, flexible, hair-width strands of ultra-pure glass. Optical fibres are formed when preform blanks portions of specially manufactured glass are heated to between 3000 and 4000 degrees and then drawn out at a rate of up to 66 feet per second

- It can transmit larger quantities of data with far less loss, maintain signals over long distances, carries little risk of corrosion, and virtually free from interference

- The light in a fibre-optic cable travels through the core by constantly bouncing from the cladding. 

The following connectors is an example of the fibre optic cable connector. The common type of connector used is ST & SC connector. 

3. Unshielded & Shielded Twisted Pair

Unshielded (UTP)

- Has 4 pairs of wire inside the jacket

- Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices

Shielded (STP)

- Two individual wires wrap in a foil shielding

- Shielding to help provide a more reliable data communication

The common connector used in this both cable is RJ-45 type connector

Now lets take a look at networking equipment/hardware needed in processing data and communication within the network 

1. Server

- A Computer Server is a computer program that provides services to other computer programs and their users) in the same or other computers

- It has large amount of RAM and fastest networking card processor installed to support/provide network smoothly. 

- Network operating system software resides on this computer, along with any software applications and data files that need to be shared.

2. Workstation

- Computer/device that connect in a network are called workstation

- It must have a network interface card, networking software, and the appropriate cables

- The workstation doesn't require large storage capability because it can be saved in file server

3. Network Interface Card

- Provide physical connection between network and workstation

- The performance of the network card is one of the major factor in determine the performance of network

- There are 3 most common network interface connections:

i. Ethernet cards

ii. LocalTalk connectors

iii. Token ring cards

4. Hubs

- Transmit all data received to all node connected to the hub
- Act as central connection point






5. Switch

- A switch serves as a controller, enabling networked devices to talk to each other efficiently
- Through information sharing and resource allocation, switches save businesses money and increase employee productivity
- Can connect Ethernet, token ring, fibre channel or other types of packet switched network segments together to form an internetwork
- Identifies the device on the network for which the data is intended and sends the data to that node only

6. Repeater

- A repeater is a device that boosts a network’s signal as it passes through
- It works by electrically amplifying the signal it receives and rebroadcasting it
- Repeaters require a small amount of time to regenerate the signal

7. Bridges


- A bridge monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location
- It can inspect each message and, if necessary, broadcast it on the other side of the network
- Bridges can be used to connect different types of cabling, or physical topologies but in the same protocol
-  Only a Translation bridge will allow two networks of different architectures to be connected

8. Routers

- A router translates information from one network to another similar to a super-intelligent bridge
- Routers select the best path to route a message based on the destination address and origin
- The router can direct traffic to prevent head-on collisions and smart enough to know when to direct traffic along back roads and shortcuts
- It can then redirect data around those sections until they clear up
- The router can be connected across fibre optic, coaxial, and twisted-pair cabling





The routers wrap up today's post about cabling & hardware. In next update, I will discuss about few types of wireless network nowadays. Thank you. :)

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Lesson 3 - Computer Networking

Assalamualaikum and greetings.
Starting from today's update, some of the blog's update will be using English to enhance my English skills and preventing from misunderstanding the terms used. :)

In today's update, I will explains about some topics in Computer Networking such as:

A. Definition of Computer Network

B. Type of Network

C. Network Component

D. Networking Architecture

E. Network Topology

A. Definition of Computer Network

A computer network is a group of computer systems and other computing hardware devices that are linked together through communication channels to facilitate communication and resource-sharing among a wide range of users electronically.

B. Type of Network

1. Personal Area Network (PAN)

- Network of personal devices

- Example: Computer > Printer, Connection between mobile devices.

2. Local Area Network (LAN)

- Covers relatively small geographical area

- Example: at home, school, office

- Allows emails, accessing the internet, file exchange or printer sharing

3. Wide Area Network (WAN)

- Covers large geographical area

- Consists of two or more LAN connected using communication technology

- This mode of telecommunication allows a business to effectively carry out its daily function regardless of location. 

4. Metropolitan Area Network (MAN)

- Network designed to service a metropolitan area, a city or a country 

- Owned or provided by a city or network provider 

C. Network Component

1. Hots/End Nodes

- The data source and the data destination

- Examples: Personal Computers, Terminals, Workstations

2. Transmission Media

- For data transmission and control signals

- 2 ways: Bounded (wired) or unbounded (wireless)

3. Network Electronic Device

- Provide interface between different media transmitter or for different protocol

- To connect multiple network together or to connect computer or network to the internet 

- Example: Bridges, Routers, Hubs, Switches

4. Applications/Software

- Software in the network functions to ensure data is delivered at respective destination 

- The applications at the end nodes normally involves technique and protocols

- The protocol determines the rules and procedure to send data, terminate data, interpret data, present data and control mistakes

D. Network Architecture & Protocol

- Ensure interoperability between various devices and equipment made by different vendors

- Enable devices made by different companies to work or communicate with each other

- 2 types: 

Client/Server Networks:

- Client: Computers that request or utilize network resources

- Server: Processing the request by client

- Download: Retrieves file from server

- Upload: Transfer from client to server

Peer to Peer Networks:

- Have direct access to other devices attached to the network

- No central server

- Example: Infrared/Bluetooth between phones, iTunes

E. Network Topology

- The arrangement or mapping of the elements of a network, especially the physical (real) and logical (virtual) interconnections between nodes

- 2 types:

Physical:

1. Linear bus:

- Consists of central cable to which all devices are connected with a terminator at each end

- Data transmitted through the bus line from one device to the other

- Network cannot function when the bus line fails

- All nodes are connected to the linear cable

2. Ring:

- Each of the systems is connected to its respective neighbour forming a ring

- The main difference between the bus and ring is that the ring topology does not require termination

- The systems are connected all together in a loop, there is no beginning and end point as there is with the bus topology

- No terminator and no bounce back signal

3. Star:

- All networked devices are connected directly to the central device

- Data on a star network passes through the hub or concentrator before continuing to it destination

- The hub or concentrator manages and controls all functions of the network

4. Tree 

- Can incorporate structures such as ring, star and bus network in one large network

- It consists of groups of star-configured workstations connected to a linear bus backbone cable

- Allow for the expansion of an existing network, and enable schools to configure a network to meet their needs

5. Mesh

- Redundant physical connections to one another

- When the mesh network is a WAN or LAN that is divided into multiple subnets, routers make decisions about which of the multiple available paths will be taken

Logical

- The way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices

- 2 ways:

a. Shared Media

- All the systems have the ability to access the physical layout whenever they need it

- Advantage: The systems have unrestricted access to the physical media

- Disadvantage: If two systems send information out on the wire at the same time, the packets collide and kill both packets

b. Token Based

- When a system needs to send out packets, it grabs token off of the wire, attaches it to the packets that are sent, and sends it back out on the wire

- As the token travels around the network, each system examines the token

- When the packets arrive at the destination systems, those systems copy the information off of the wire and the token continues its journey until it gets back to the sender

- When the packets arrive at the destination systems, those systems copy the information off of the wire and the token continues its journey until it gets back to the sender

- The ring topology best facilitates this requirement

That's all for lesson 3 contents update. In lesson 4, I will share about Cabling & Hardware. Mucha Gracias :)

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