....MESH Topology & TREE Topology....

MESH Topology

A mesh network is a local area network (LAN) that employs one of two connection arrangements, full mesh topology or partial mesh topology. In the full mesh topology, each node (workstation or other device) is connected directly to each of the others. In the partial mesh topology, some nodes are connected to all the others, but some of the nodes are connected only to those other nodes with which they exchange the most data.

A mesh network is reliable and offers redundancy. If one node can no longer operate, all the rest can still communicate with each other, directly or through one or more intermediate nodes. Mesh networks work well when the nodes are located at scattered points that do not lie near a common line.

The chief drawback of the mesh topology is expense, because of the large number of cables and connections required. In some scenarios, a ring network or star network may prove more cost effective than a mesh network. If all the nodes lie near a common line, the bus network topology is often the best alternative in terms of cost.

TREE Topology

is a combination of the bus and the Star Topology. The tree like structure allows you to have many servers on the network and you can branch out the network in many ways. This is particularly helpful for colleges, universities and schools so that each of the branches can identify the relevant systems in their own network and yet connect to the big network in some way.

A Tree Structure suits best when the network is widely spread and vastly divided into many branches. Like any other topologies, the Tree Topology has its advantages and disadvantages. A Tree Network may not suit small networks and it may be a waste of cable to use it for small networks. Tree Topology has some limitations and the configuration should suit those limitations.

The Tree Topology follows a hierarchical pattern where each level is connected to the next higher level in a symmetrical pattern. Each level in the hierarchy follows a certain pattern in connecting the nodes. Like the top most level might have only one node or two nodes and the following level in the hierarchy might have few more nodes which work on the point to point connectivity and the third level also has asymmetrical node to node pattern and each of these levels are connected to the root level in the hierarchy. Think of a tree that branches out in various directions and all these branches need the roots and the tree trunk to survive. A Tree Structured network is very similar to this and that is why it is called the Tree Topology.

...chan...

30 Aug 2009 Sunday

Today Miss Azura gave us lecture of chapter 5 session 2, continue with data communication. It is introduced network fundamentals, communication devices, such as workstations and routers, file server. Besides that, Miss Azura also talked about advantages and disadvantages of network, local area networks (LANs). There are two types of LANs which are peer to peer networks and client server networks. The following topic is LAN topology, there are three types in note which are ring, star and bus. Furthermore, we need to find intro about what are mesh topology and tree topology.



...chan...

Twisted Pair Wired vs Coaxial Cable vs Fiber Optic Cable

Twisted Pair Wired
Advantages
~ inexpensive and readily available
~ flexible and light weight
~ easy to work with and install

Disadvantages
~ susceptibility to interference and noise
~attenuation problem
~ for analog, repeaters needed every 5-6km
~ for digital, repeaters needed every 2-3km
~ relatively low bandwidth (300Hz)

Coaxial Cable
Advantages
~ higher bandwidth - 400 to 600 Mhz
- up to 10800 voice conversations
~ can be tapped easily (pros and cons)
~ much less susceptible to interference than twisted pair

Disadvantages
~ high attenuation rate makes it expensive over long distance
~ bulky

Fiber Optic Cable
Advantages
~ greater capactity (bandwidth of up to 2 Gbps)
~ smaller size and lighter weight
~ lower attenuation
~ immunity to environmental interference
~ highly secure due to tap difficulty and lack of signal radiation

Disadvantages
~ expensive over short distance
~ requires highly skilled installers
~ adding additional nodes is difficult


...chan...

~~ UTP & STP ~~

UTP >> Unshielded Twisted Pair








STP >> Shielded Twisted Pair




...chan...

26 Aug 2009 Wedenesday

Today Miss AZura gave us chapter 5 lecture, talked about data communication, such as what is data communication, moving data, data transmission, transmission media, wired transmission media, and wireless transmission media. After finished lecture, Miss Azura explain to us why we would got the mark in our quiz one by one.


...chan...

23 Aug 2009 Sunday

Absent today because I was sick..
Sorry for the absent, Miss..


...chan...

12 August 2009 Wednesday

Today Miss Azura was absent and replace by Encik Mot..very suprise to saw Encik Mot after I came into the class..still got quizz, i tot canceled already..haha..
very ashamed with the quiz...

Miss Azura, take good care..


...chan...

9 Aug 2009 Sunday

Today Miss Azura continue chapter 4 lecture, something about online annoyances and internet & www. The online annoyances includes spam, pop-ups, cookies, malware, spyware and phishing & hoaxes. After that, Miss Azura gave us lecture about the origin of the internet, which are ARPANET, TCP/IP, NSFNET and INTERNIC. Then Miss Azura showed us some Asia Internet Statistic. Besides that, Miss Azura also intro some internet connection for us such as client computers, server computers, broadband connections and satellite connections. Finally, Miss Azura mention about internet service providers, there are 2 categories which are ISP and OSP.
Before dismissed the class, MIss Azura announced that got quiz on Wednesday...HAizzz..


...chan...

^^ MyEG Portal^^ vs ^^ Rilek Portal^^

^^ MyEG Portal ^^

~~ MyEG Services Berhad is a concessionaire for the Malaysian E-Government MSC Flagship application. MyEG offers the public a single point of contact between the government and the public through their portal. The services they provide including renewing road tax, car insurance, paying summonses, Kuala Lumpur City hall assessment and even some utility bill payments. This portal enables Malaysians to dynamically interact with numerous agencies within the Federal, State and the Local Government machinery providing services ranging from information searches to licence applications.
MyEG was officially launched on April 17 2008.

http://www.myeg.com.my



^^ Rilek Portal ^^

~~ELECTRONIC TRANSACTION
Introducing RILEK as the revolutionary way to perform all your e-government services:

Jabatan Pengangkutan Jalan (JPJ)
Polis DiRaja Malaysia (PDRM)
Telekom Malaysia Berhad (TMB)
Tenaga Nasional Berhad (TNB)

RILEK offers JPJ Driving Licences services, summons payments and inquiries on Kejara points, include electronic utility bill payment for TNB and Telekom bills. Go online and experience hands-on the technologically advanced payment method, minus the hassle, queues, and frustrations. You can complete all your billing payments and inquiries in an instant, comfortably from anywhere.

http://www.rilek.com.my/




...chan...

...< B2C >...< B2B >...< B2C >...

...< B2C >= business to consumer~~ describes activities of commercial organizations serving the end consumer with products and/or services. It is also a form of electronic commerce in which products or services are sold from a firm to a consumer. An example of a B2C transaction would be a consumer buying grain-fed chickens at a grocery store.

...< B2B >= business ti business~~ typically takes the form of automated processes between trading partners and is performed in much higher volumes than business-to-consumer (B2C) applications. For example, a company that makes chicken feed would sell it to a chicken farm, another company, rather than directly to consumers. B2B can also encompass marketing activities between businesses, and not just the final transactions that result from marketing.

...< C2C >= consumer to consumer(or citizen-to-citizen)~~ involves the electronically-facilitated transactions between consumers through some third party. A common example is the online auction, in which a consumer posts an item for sale and other consumers bid to purchase it; the third party generally charges a flat fee or commission. The sites are only intermediaries, just there to match consumers. They do not have to check quality of the products being offered.


...chan...

5 Aug 2009 Wednesday

Today Miss Azura gave us lecture about computer communication involve internet communications, internet multimedia and e-commerce. There are a few things very similar for me like weblogs, chat room, e-mail and newsgroup. After that, Miss Azura gave us some homework( assignment??) to do. By the way, today is a good day for me...^^


...chan...

2 Aug 2009 Sunday

After one week Influence H1N1 holiday, I was back to UUM at 10.30am today. Lol...my tech comm class started at 11am, very tired and very very wish to sleep when I reached my room. But I insist to go to the class because I have three classes continuously. I was late for my first class, that was ashame when into the class because Miss Azura was there and started her lecture. Miss Azura continue her lecture about computer technology. After lecture, Miss Azura also remind us about the pop quiz, hope the pop quiz not very dificult.

** Miss Azura, sorry for the late. **



...chan...