Computer Network
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.
Figure 1
What is Computer Network
Figure 2 Computer Network classified by Area Width
Figure 3 Types
of Network Topology
Figure 4
Star/Extended Star Topology
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.
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.
ไม่มีความคิดเห็น:
แสดงความคิดเห็น