Types of Network Topology

Network Topology is the schematic description of a network arrangement, connecting various nodes(sender and receiver) through lines of connection.

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BUS Topology

Bus topology is a network type in which every computer and network device is connected to single cable. When it has exactly two endpoints, then it is called Linear Bus topology.

Features of Bus Topology

1. It transmits data only in one direction.
2. Every device is connected to a single cable

Advantages of Bus Topology

1. It is cost effective.
2. Cable required is least compared to other network topology.
3. Used in small networks.
4. It is easy to understand.
5. Easy to expand joining two cables together.

Disadvantages of Bus Topology

1. Cables fails then whole network fails.
2. If network traffic is heavy or nodes are more the performance of the network decreases.
3. Cable has a limited length.
4. It is slower than the ring topology.

   RING Topology

   It is called ring topology because it forms a ring as each computer is connected to another computer, with the last one connected to the first. Exactly two neighbours for each device.
   

Features of Ring Topology

1. A number of repeaters are used for Ring topology with large number of nodes, because if someone wants to send some data to the last node in the ring topology with 100 nodes, then the data will have to pass through 99 nodes to reach the 100th node. Hence to prevent data loss repeaters are used in the network.
2. The transmission is unidirectional, but it can be made bidirectional by having 2 connections between each Network Node, it is called Dual Ring Topology.
3. In Dual Ring Topology, two ring networks are formed, and data flow is in opposite direction in them. Also, if one ring fails, the second ring can act as a backup, to keep the network up.
4. Data is transferred in a sequential manner that is bit by bit. Data transmitted, has to pass through each node of the network, till the destination node.

Advantages of Ring Topology

1. Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.
2. Cheap to install and expand

Disadvantages of Ring Topology

1. Troubleshooting is difficult in ring topology.
2. Adding or deleting the computers disturbs the network activity.
3. Failure of one computer disturbs the whole network.

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STAR Topology

In this type of topology all the computers are connected to a single hub through a cable. This hub is the central node and all others nodes are connected to the central node.

Features of Star Topology

1. Every node has its own dedicated connection to the hub.
2. Hub acts as a repeater for data flow.
3. Can be used with twisted pair, Optical Fibre or coaxial cable.

Advantages of Star Topology

1. Fast performance with few nodes and low network traffic.
2. Hub can be upgraded easily.
3. Easy to troubleshoot.
4. Easy to setup and modify.
5. Only that node is affected which has failed, rest of the nodes can work smoothly.

Disadvantages of Star Topology

1. Cost of installation is high.
2. Expensive to use.
3. If the hub fails then the whole network is stopped because all the nodes depend on the hub.
4. Performance is based on the hub that is it depends on its capacity

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MESH Topology

It is a point-to-point connection to other nodes or devices. All the network nodes are connected to each other. Mesh has n(n-1)/2 physical channels to link n devices.

There are two techniques to transmit data over the Mesh topology, they are :

1. Routing
2. Flooding

MESH Topology: Routing

In routing, the nodes have a routing logic, as per the network requirements. Like routing logic to direct the data to reach the destination using the shortest distance. Or, routing logic which has information about the broken links, and it avoids those node etc. We can even have routing logic, to re-configure the failed nodes.

MESH Topology: Flooding

In flooding, the same data is transmitted to all the network nodes, hence no routing logic is required. The network is robust, and the its very unlikely to lose the data. But it leads to unwanted load over the network.

Types of Mesh Topology

1. Partial Mesh Topology : In this topology some of the systems are connected in the same fashion as mesh topology but some devices are only connected to two or three devices.
2. Full Mesh Topology : Each and every nodes or devices are connected to each other.

Features of Mesh Topology

1. Fully connected.
2. Robust.
3. Not flexible.

Advantages of Mesh Topology

1. Each connection can carry its own data load.
2. It is robust.
3. Fault is diagnosed easily.
4. Provides security and privacy.

Disadvantages of Mesh Topology

1. Installation and configuration is difficult.
2. Cabling cost is more.
3. Bulk wiring is required.

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TREE Topology

It has a root node and all other nodes are connected to it forming a hierarchy. It is also called hierarchical topology. It should at least have three levels to the hierarchy.

Features of Tree Topology

1. Ideal if workstations are located in groups.
2. Used in Wide Area Network.

Advantages of Tree Topology

1. Extension of bus and star topologies.
2. Expansion of nodes is possible and easy.
3. Easily managed and maintained.
4. Error detection is easily done.

Disadvantages of Tree Topology

1. Heavily cabled.
2. Costly.
3. If more nodes are added maintenance is difficult.
4. Central hub fails, network fails.

5 Classification of Networks by Scale

In network technology we discussed classification of networks by their topology. Another important criterion for classifying networks is their scale (physical size). As shown in Figure 8 there are:

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

Personal Area Network (PAN) - The interconnection of devices within the range of an individual person, typically within a range of 10 meters. For example, a wireless network connecting a computer with its keyboard, mouse or printer is a PAN. Also, a PDA that controls the user's hearing aid or pacemaker fits in this category. Another example of PAN is a Bluetooth. Typically, this kind of network could also be interconnected without wires to the Internet or other networks.

Local Area Network (LAN) - Privately-owned networks covering a small geographic area, like a home, office, building or group of buildings (e.g. campus). They are widely used to connect computers in company offices and factories to share resources (e.g., printers) and exchange information. LANs are restricted in size, which means that the worst-case transmission time is bounded and known in advance. Knowing this bound makes it possible to use certain kinds of designs that would not otherwise be possible. It also simplifies network management. Traditional LANs run at speeds of 10 Mbps to 100 Mbps, have low delay (microseconds or nanoseconds), and make very few errors. Newer LANs operate at up to 10 Gbps.

Metropolitan Area Network (MAN) - Covers a larger geographical area than is a LAN, ranging from several blocks of buildings to entire cities. MANs can also depend on communications channels of moderate-to-high data rates. A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MANs might also be owned and operated as public utilities. They will often provide means for internetworking of LANs. Metropolitan Area Networks can span up to 50km, devices used are modem and wire/cable.

Wide Area Networks (WAN) - Computer network that covers a large geographical area, often a country or continent. (any network whose communications links cross metropolitan, regional, or national boundaries). Less formally, a network that uses routers and public communications links. Routers will be discussed later.

AKTIVITI CNY 2018

Assalamualaikum.. haiii..🙆🙋 now aku nak kongsi skit apa yang aku buat sepanjang cuti CNY baru- baru ni..✌  tak dak la nak cita semua.. aku cerita yang menarik ja la..🙊

kolej matrikulasi Kedah bercuti selama 9 hari.... jadi aku tidak  melepaskan peluang untuk mengisi masa lapang aku sepanjang cuti ni.... Of course laa kita balik spend masa dengan family.💖 terutama sekali abah aku dan my sistarr..💟 memang la melepaskan rindu yang tak terkira.. walaupon kalau dok dekat-dekat asyik nak gaduh ja..😎 tapi kalau dengan rindu dok jauh ni... tak la nak kata.. dengan dok buat sesi luahan perasaan masing-masing.😜😜 my abah of course lah kalau aku balik nak makan yang ni la yang tu la.. so aku layankan ja la my abah nak makan apa.. bahan masak semua abah yang beli so aku ni jadi chef ja la.🙌🙌

ada jugak part aku p jejalan dengan kawan. orang Kelantan kata derak..😋 hahah.. pergi la spend masa dengan kawan. pergi makan, shopping, tengok wayang dan cuci-cuci mata. Ada hari pergi Aman Central..😁😁 tinggal kat Sungai Petani berjalan sampai Aloq Staq tu. Tak dak la jalan kaki kan..😂 Tapi nak cerita kata jauh tu berjalan. Makan kat Seoul Garden tu la best.💕 Hahahah. Menghabiskan duit.. Tapi my sistar kata habis duit sebab makan tak pa..Tapi still ingat nak bawak balik kat abah baju Polo Club satu kat abah..💓💓 Ok .. Dah sudah menghabiskan duit, balik lah rumah dok dediam..💆 Ada la keluar pi beli barang dapoq kat tesco, econsaves dan ikan tepi rumah.. Hahahaha.. 💃💃

Kembalilah jadi chef tak berbayar.. Tak pa saya dengan suka rela nya menyandang jawatan itu.🙇🙇 Bukan selalu nak bagi my abah makan air tangan kita.. Bukan setakat air tangan nak bagi kalau boleh dengan air kaki pon nak bagi.. huhuhuhu.. Tapi tak boleh sat gi anak derhaka pulak.. Masuk paper tak pasai ja..💁

Sebenar nya balik ni ada  misi.. Misi aku adalah untuk mengembalikan berat badan my abah yang dah susut sangat.✌✌ Sebab dia dok diet jaga badan lah konon nya, pahai kita tau dia tak suka makan kat kedai..👀 Takpa abah itu bagus, tak mak cik Petani tu nati dok ngorat abah😡😡bukan nak marah kalau abah nak cari pengganti... Kita tau abah sunyi dok sorang kat rumah.. Tapi biaq la yang elok sikit nak jaga abah.. Ok dah cukup mengarut.. Misi tadi nak naikkan berat badan abah.. So must cooked very well.. Sebab nak tambah selera abah... hahahah..🙈🙈 Tak sia-sia abah makan banyak ari tu.. Suka tengok.. 

Walaupon aku masak kari telur dengan kentang ja pon..😄 Abah makan dengan jayanya.. Hahahah... Tu masak simple, kalau time masak yang hebat sikit.. Abah makan lagi lahh... Seronok tengok abah makan tak boleh nak kata perasaan ini......... 😌😌kata tadi masak hebat kan?? Masak sotong pulut ja pon..💁 Biasa lah abah aku suka sotong.. hehehehe.. 

Petang-petang naik laa moto ronda-ronda..🚴🚴 Boleh lepas gian jadi minah rempit masa cuti.. Hahahah.. Naik moto lagi nikmat bila ronda dari naik kereta.. Menikmati keindahan tuhan yang Maha Esa.. Tengah syiok ronda tak sedar yang minyak dah tinggal suku..😂 Nasib baik perasaan.. Masyaallah.. Kalau dak menuntun lah aku ke jalan yang benar.. Hahahahaha... 

Dah cerita.. Sat gi jadi novel pulak.. Itu aktiviti masa cuti CNY.. Kalau ada masa lagi, nanti aku cerita lain... Byee... Assalamualaikum....🙇🙇

DC035 COVER BOOK ( COMPUTER SCIENCE )

Kulit buku untuk matapelajaran computer science bagi tahun 2018 sesi 18/19 ( DC0325 ).

DC035