C1006 Computer Networks Term 3 2007 Assignment – Part 3
IV. Network Parts and Devices Explanation
In this part, I will give an explanation for every parts and devices that we can see in my network diagram. As we can see in the diagram, my network design has some parts and devices, the switch, Desktop PCs, Server, Printer, Fax machine, Router, Firewall, DSL modem, category 5 UTP cable, and Internet. And here is the explanation for each of them.
a) Switch
Switch is a networking device that acts as the central connection point in my network design. It works in physical and data link layer of the OSI model. Every computer in this network has a direct link to the switch. The switch itself enables communication between computers or network devices that connected to it.
In the old times, a network with star topology use a hub as the central connection point. But nowadays, switches have replaced the hub in most networks. (Wikipedia, 2007). Although a hub and a switch has the same basic function in joining computers and network devices in a star topology, but there is a slight difference between them in their way to handle data traffic in the network. If we use a hub, when a computer wants to make a data transmission, it will send the data to the hub first, and then the hub will forward the data signal to all the network segments attached to it. It may happen that two computers make a data transmission at the same time, and then a collision will happen and destroy both data signal. On the other hand, if we use a switch, when there is a computer wants to make a data transmission, the data will be sent to the switch first, the switch can recognize the data packet’s address, and then the switch will forward the data packets just to the intended link. With this method, a switch will greatly increase the network’s speed and minimize the chance of data collision in the network. Furthermore, a switch allows the devices in the network to communicate in a full-duplex mode, while a hub only allows communication in half-duplex. So, using a switch for a small office network will help to increase the office’s networking performance and support the office’s computing activity as it needs to do heavier processing jobs.
There are two types of switch, the managed switch and the unmanaged switch. A managed switch support more complex functions than an unmanaged switch does. Also, a managed switch is very expensive compared to the unmanaged switch. For the range of home and small office network, an unmanaged switch is preferred. (Sensiblecinema.com). so, here in my network design, I use the unmanaged switch type.
The switch that I use in my network design has 8 Ethernet ports. As we can see in my network design diagram, 6 port is used, 4 for the Desktop PCs, 1 for the Server, and 1 for the router. So, we still have 2 free ports in this switch, when the company grows and needs to add more computers, we just need to plug these new computers to any available port in the switch, if the switch’s port is full, we just need to purchase a new switch, connect and stack it to the first switch, and network can support more new computers.
The advantages of using a switch in small office network are:
1. It allows the devices in the network to communicate in full-duplex mode.
2. It forwards data transmission from one computer directly to the intended link and destination; make more efficient use of the network’s bandwidth.
3. Generally it increases the network’s speed and performance, so it can support whatever computer processing jobs needed by the company.
4. The availability of the cheap unmanaged switch makes it affordable for small office scale.
While, the disadvantages of using a switch are:
1. Because it acts as the central connection point in the network, the risk of switch failure that makes the entire network failure may happen. But we can minimize the chance of this risk to happen by using a switch from a trusted brand that has a guaranteed product quality.
2. A switch is more expensive than a hub. But the price of the switch is equal to the advantages that we get from it. And we cannot get those advantages from a hub.
b) Desktop PCs
We have seen that there are some desktop PCs in my network design diagram; we also can call these desktop PCs as a workstation. This is the computers that will be used by the office’s staffs to do their jobs in the office. A workstation is a computer that has its own processor. Basically, it is able to do a standalone processing as it also has its own input devices, monitor, CPU, and hard disk beside its processor. But in this case, we use these desktop PCs in the network, so we connect them our network system, so they able to expand their knowledge, use the shared resources in the network, and also get the other benefits of networking.
As explained in the overview, my network uses the client-server environment. Here, The desktop PCs, which seen in the diagram, acts as the client for the network’s server. They access the shared resources from the server. The benefit of placing the network’s desktop PCs as a client is that we don’t have to purchase a peripheral like printer or expensive applications for each of these desktop PCs, because as a client in the network, they can share these peripheral or applications from the network’s server, so we can save the company’s money with this method. For example, although in this network, the office starts with four desktop PCs, it won’t need to buy a printer for each desktop PC, because it acts as a client that can access and use just one printer shared in the network.
c) Server
In my network design, there is a special computer that we call as the server, because this network design uses a client-server environment. The server’s job is to manage the network and share the network’s resources to be accessed by the clients. To carry out its job, the server computer is equipped with more powerful hardware than the client computers. It also has special software to support its function, such as NOS (Network Operating System).
The NOS is used by the server to manage and control both the server’s system and also the communication of the devices in the network. It enables the server to connect all the network’s devices into an interactive environment and control their function. It also allows the server to maintain the network’s security and privacy. In my network design, the server computer use Windows Vista Business Edition as the NOS. I choose using Windows Vista because it’s the latest operating system, so our network will be able to follow information technology growth in following few years and not become outdated so soon.
The advantages that we get from using a server are:
1. Better Network Performance
Due to the fact that the server computer is supported by powerful computing equipment, so the server will give a better performance for the network. When the company grows and need a bigger network with more client computers, the server will easily support it because basically a network with client-server environment has adequate performance to support more than ten users.
1. We don’t need to Have All the Office’s Staff as Sophisticated Computer User
The server computer provides us with the ability to do centralized management of the network. Some important settings can be set from the server and we don’t have to rely on each office’s staff to do these things. So, the company won’t have to give all staff an advanced computer training that needs expensive cost to hold. But the office’s staffs just need a basic computer training that give them knowledge just to do their job using the computer and also some basic safety procedure that they need to know; this kind of training is cheaper and saves the company’s money.
1. Centralized Security and Privacy Control
With the use of the server, we can set up the security level for the entire network. So the network will has a better security level because there is just one security standard applied for the entire network. Additionally, the office may want to set some files or data to be accessed just by some person rather than all the office’s staffs. This is possible with the use of the server to set this kind of privacy setting.
1. Centralized File Management
Centralized file management is very important for a working environment. There will be many staffs that use various files, every time when an office’s staff uses the computer and wants to open a file; he/she will always know where to find the needed file. Because all the office’s file can be stored in the server, it is not scattered in many computer system, so the office’s staff will work more efficiently with this condition.
1. Saving the Company’s Money on Hardware and Software
As explained before, the server is able to share the network’s resources to the client computers. This means that when we need to use an application or software, we won’t have to install this software on each client computer. We just need to have this software or application installed just in the server computer and when the clients need to use it; they can just copy from the server and use it in their own computer. We also can get the same benefit for hardware. For example, in my network design diagram we just see one network printer; we just need that one printer to be shared by all the client computers in the network. It again saves the company’s money.
1. Easier to Make Data Backup
Data backup is an important issue as we will use this network for the company’s business activities; it will hold a lot of important data and information, so we cannot risk a total lost of these kinds of data. The solution is to make a data backup. With using a server as the main place to store and organize the office’s data, backup process just need to be done from the server. In another word, it is simple and easy.
For the disadvantages of using server, it is mostly the same with the disadvantages of client-server environment that I have explained in my overview, which is the cost to provide the server and dependency on the server. I just want to add one more point that is a server will need an administrator to do the server maintenance. But as we talk on the scope of small office network, we don’t need to hire a dedicated full time network administrator. We can just hire a part time network administrator for this time. When the company grows in the future, then we may consider to hire a full time network administrator for the network has grow bigger and bigger.
d) Network Printer
Network printer is a printer that shared by the users in the network. In this case, the company already has a printer, so I use the company’s printer in my small office network design. I connect it to the server to allow the client computers to share the use of this single printer. The server itself will manage the printing job queue from the clients.
e) Fax Machine
Just like the printer, the company also has a fax machine. Because basically a fax machine doesn’t work by connecting it to a computer, so in my network design diagram, I just connect the company’s fax machine to the telephone line. All the office’s staffs can use this fax machine by come to this machine, and use it; that’s how the fax machine in this network design works.
f) Router
Router is an internetworking device that works in the physical, data link, and network layer of the OSI model. A router is able to connect two or more networks with different architecture and different media. It also allows two independent networks to communicate each other while they still can do their own function independently.
A router is efficient in handling network traffic and data transmission between different networks with multiple paths. The router handles data transmission between networks by selecting the best and the most economical path to transmit each packet from the sender to the receiver (this process also known as routing). It does this function by using a routing table that keeps the network addresses.
That’s about the general function of a router. Now let’s talk about the router that I use in my small office network design. Here, I use a D-Link Ethernet Broadband Router EBR-2310 as the network’s router. This router has adequate features that we need for our small office network such as built-in 4 switch port, advanced firewall features, parental control, Internet connection sharing, etc. We can use the switch port at this router to add a new computer when our switch capacity is full or we can use it to connect our network with another network as needed. The firewall features such as NAT (Network Address Translation), MAC filtering, Website filtering, and scheduling are useful to protect our network from any possible attack from the Internet as the router handles all the data packets movement from and into our network. We can use the parental control feature to block some websites such as websites that suspected to contain viruses or any malicious software. The most important thing is that by using this router we able to share the company’s high speed DSL Internet connection for the entire network.
The benefits that we can get from using a router in our small office network are:
1. Internet Sharing Ability
As explained before, we can share the company’s internet connection for all users in the entire network.
1. Internet Security
The firewall features that provided by the router will give our network better security for its Internet connection.
1. Ability to Connect Our Network with Another Network
For the router is an internetworking device which able to connect several different networks, so with the use of a router in the office’s network, the office’s network has the ability to be connected to another network if needed. For example, maybe the company will grow further in the future; renovate its small office to a bigger one with two storeys, and it want different network architecture for the network in the second storey. If that happens, these two networks can be connected easily by using this router.
g) Firewall
Generally, firewall is a kind of software that protects our network from many possible threats from the Internet. I will give more explanation about firewall later in the network’s security measures and countermeasures part. Because there is also firewall hardware in the market, so in this part, I just want to make it clear that the firewall that we seen in my small office network diagram is not hardware, it is a software firewall that we get from the router to give the network protection and security from the network’s Internet connection.
h) DSL Modem
DSL is an abbreviation from Digital Subscriber Line. It is a kind of Internet connection technology that allows us to have a broadband Internet connection using ordinary copper telephone wire. DSL uses digital data, so we still can use our telephone line while we use it for Internet connection at the same time, that’s why we can use the office’s telephone line for both the DSL modem and the fax machine. While, the DSL modem is the device that we need when using DSL Internet connection. (TechTarget, 2007).
Since the company already has a high speed DSL Internet connection. So, I use the company’s DSL modem in my network design. I connect the DSL modem to the network’s router so the router will enable the Internet connection to be shared for the entire network.
i) Category 5 UTP Cable
As explained in the overview, my network design is a wired network. I choose to use the category 5 UTP cable for my network’s wire.
UTP cable stands for Un-shielded Twisted Pair cable. It is cheaper than the other network cables such as STP (Shielded Twisted Pair) cable or Fiber Optic cable. It has some pair of twisted cable. The cable twisting is done to reduce the affect of noise and EMI (Electro Magnetic Interference) to the signal in carried by the cable. It has 7 different categories, category 1, category 2, category 3, category 4, category 5, category 5e, and category 6. (TheNetworkAdministrator.com, 2001). The higher the category level, the higher the cable performance to support higher bandwidth.
The category 5 UTP cable that used in my network design has four pair of twisted cable inside it where the pair of individual cable is twisted, then all four pair is twisted. It can be used to cable a 10Base-T (Ethernet) which has a bandwidth of 10 Mbps or 100Base-T (Fast Ethernet) which has a bandwidth of 100 Mbps.
Since my network design is designed to use the 10Base-T Ethernet network, I consider that using this category 5 UTP cable is a good choice because if the network grows in the future and the company needs a faster network connection with upgrading the network to 100Base-T Fast Ethernet, the company won’t have to replace the existing cable because it is ready to support such upgrade. In another words, using this type of cable is a good investment for the company’s small office network.
j) Internet
Internet is a worldwide network. It was firstly known as ARPANET that developed by ARPA (Advanced Research Projects Agency) in 1969. Actually it was used to connect computers among universities which enable them to communicate with each other. (TechTarget, 2006).
Today, Internet can be accessed by almost all people in the world. Every people may use the Internet to get information, share data, talk to another people in different part of the world, etc.
The most accessed feature of the Internet is the WWW (World Wide Web). It has a feature called hypertext that allows cross-referencing among websites (hyperlink). This feature is used in all websites that we can found in the Internet.
The other features that mostly used by Internet users are the electronic mail (e-mail), chat using Internet Relay Chat (IRC), and also Voice over Internet Protocol (VoIP) which enables an Internet users to make a phone call to another Internet user worldwide.
It’s good that this company already has an Internet connection for its office’s network. So, it can use the Internet to help with its business activities. For example, the company can use the e-mail to make written communication with its customer, use the chatting feature of the Internet to provide real-time customer support, make a website to advertise the company worldwide, etc.
Beside the benefits that the company can get from its network Internet connection, the company also has to be aware that its network Internet connection may be the source of many dangerous threats which may harm its small office network. Because Internet can be accessed worldwide, so there are wide variety of Internet users which include some people who want to harm another people’s network or computer. But with applying adequate Internet security for the company’s small office network, we can prevent such Internet threats to harm our network.
This is the end of the fourth part of this assignment. In this part, I have explained about each part and device that we can see in my small office network diagram such as the Switch, Desktop PCs, Server, Network printer, Fax machine, Router, Firewall, DSL modem, UTP cable, and the Internet. In the next part, I will explain about the network and Internet vulnerabilities.
To be continued in the next post….
Do you have any comment on this? maybe you have something to ask me or want to discuss with me about this?Or maybe you are IDIC student and taking this module also?
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