What is Computer Network? Why?
If any computer is not connected to others it is called "a stand-alone machine". Today if anyone uses any stand-alone machine , he must be considered a stranger because the world today is of computer networks. A network machine can send/receive packets (bits of data per second) to/from any other machines e.g. Internet. Our computers/tablet PCs/smart phones can never be alone anymore. Yes, they have been connected to their networks both local (e.g. the networks in our school) and global (e.g. Internet). We can share our resources such as files, printers etc. to each other through our local area network (LAN) or we can exchange our data through the wide area network (WAN) like Internet.
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| Figure 1 What is Computer Network |
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| Figure 2 Computer Network classified by Area Width |
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| Figure 3 Types of Network Topology |
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| Figure 4 Star/Extended Star Topology |
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| Figure 5 The Client-Server Network What/How |
What/How of the Network in Comp102 Classroom?
Because the operating software (OS) of all computers in classroom-102 is Windows7, so the students who uses them, those machines, should better understand how they work, especially how to use the network of them.
Our computers in comp102 classroom are connected together with the UTP (unshielded twisted pair) cables. Why? Because the unshielded cables are lower cost than the shielded cables which have been used in the signal noisy areas e.g. airports, factories, etc. The style of their connection is "Star Topology" which each machine has its own cable which connects directly to the hub/switch. A hub/switch is the center point of cables (both devices are similar to each other but a switch is more clever than a hub) . Well our network is called Local Area Network (LAN). Any LAN must has its workgroup name which required by the Operating System (OS) of each computer, Windows7 . But the administrator (the teacher) of this LAN named it "comp2"workgroup.
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| The Teacher Teaches About Programming Using C-Language in Comp102 Classroom |
If we consider only the "comp2-workgroup LAN", it is a peer-to-peer network that every machine is independent from each other but shares its files/folders/printers to its peers. On the other hand, when this workgroup connects to the server computer of"the School Media Center", it must be a client-server network.
What is about the client-server network? It means that the server computer of "the Media Center" is the manager/boss of other computers which are only the clients. The server computer has been installed with the operating-software-for-server such asWindows2003server/Windows2008server , Linux or Unix, which can manage the client computers of the network. The clients have to obey the server because the latter has the power to control/ban the former. Yes, the clients can never control/manage the server.
Every machine in the network is required to have its unique"hostname" and "IP address". Only the server computer has the"static IP address" while the IP addresses of the client computers are "dynamic" specified/controlled by the sever. If the user of any client computer specify the static IP address himself, the server computer can never share the Internet connection because the "IP address conflict" problem could be occurred easily. Then the alien client will be kicked off /faded away from the network simultaneously. Yes, the server computer is the "Internet gateway" of the network.
OK., after selecting the "Local Area Network" option, the "Local Area Network Connection Status" window appears. You can see its speed of packets transmission (100 Mbps) , bytes of the sent/received packets.
Then, when you click on the "Properties" button, another window shows. To find and select the "Internet Protocol Version) option, you can see its IPaddress has been obtained automatically by the gateway/server computer (of the School Media Center).
Another one I would like to refer to is "protocol". What is it? Aprotocol is a system of digital message formats and rules for exchanging those messages in or between computing systems and in telecommunications. And in our network we use the TCP/IP (comes from "Transmission Control Protocol and Internet Protocol). Now Thailand uses IPv4 protocol, but Thai government by Prime Minister Yingluck Shinawatra is going to change the Internet protocol of the country with another version, IPv6 protocol, which has more capacity and efficiency of transmission.
