Packet Tracer Client Server & DNS Simulation (PTCSDS)


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Understanding Client Server Architecture

As explained in the previous chapter, the client server architecture model is modeled as a set of services provided by the server and one or more clients that use the server's services. The client does not need to be aware of the server, and also does not need to know the existence of other clients. There does not have to be a 1:1 mapping between processes and processors in the system. This can be seen in the example of Figure 10.2, where there is a physical architecture with 6 client computers and 2 servers. The logic of the process in Figure 10.2 is shown in Figure 10.3.

Figure 10.2 client server system
Figure 10.2 client server system

Figure 10.3 c/s architecture logic process
Figure 10.3 c/s architecture logic process

The design of the C/S architecture must consider the application logic structure shown in Figure 10.4 which shows the application divided into 3 layers, namely:

  1. presentation layer, concerned with presenting information to the user and with all user interactions.
  2. application processing layer, deals with the implementation of application logic
  3. data management layer, deals with database operations.

The simplest C/S architecture is called the Two Tier C/S architecture, where applications are organized like a server and a set of clients as in Figure 10.5 where the Two Tier C/S architecture has two forms, namely:

Thin Client Model

This model all application processing and data management is done on the server. The client is responsible for running the presentation software which is usually just a system interface / GUI.

Excess:

  • low cost
  • suitable for simple network models.

Lack:

  • placing a heavy processing load on the server
  • inefficient, because the greater processing power of modern client PCs is not optimally utilized.

Fat Client Model

In this model, the server is only responsible for data management. The client device is responsible for application logic and interaction with the user.

Excess:

  • use the greater capabilities of the client PC and distribute the processing of application logic and presentation to the clients.
  • The server only handles all database transactions.
  • more effective processing distribution.

Lack:

  • the system management is more complex
  • more expensive costs.

An example of the C/S Two Tier architecture model can be seen in Figure 10.4 about the ATM network. In the figure, the ATM is not directly connected to the customer database, but is connected to the teleprocessing monitor. The Teleprocessing Monitor (TP) is a middleware that manages communication with remote clients and serializes client transactions to be processed by the database. Using serial transactions means that the system can recover from errors without destroying system data.

The advent of free downloadable Java and applets allowed the development of C/S systems across thin and fat client models. Some application processing software could be downloaded to the client as Java applets, reducing the server load. The UI was built with a web browser that could run Java applets.

The most important problem in two tier C/S architecture is that all three logical layers must be mapped to two computer systems. There may be scalability and performance problems if a thin client model is chosen. It is also possible that system management errors are possible if a fat client is chosen. To overcome this problem, an alternative approach is to use a three tier client server architecture (shown in Figure 10.5). In this architecture, it does not necessarily mean that there are 3 computers connected to the network. One server computer can run application processing, and application data management as separate logical servers. But if demand increases, the separation of application processing and data management can be done directly and execution is done on a separate processor.

Figure 10.5 three tier c/s architecture
Figure 10.5 three tier c/s architecture

The internet banking system is an example of a three-tier c/s architecture system. The bank customer database provides data management services, the web server provides application services such as cash transfer facilities, bill payment, etc. The customer's computer with an internet browser is the client. This system is easily scalable to add new web servers as the number of customers increases.

Figure 10.6 distributed architecture of internet banking system
Figure 10.6 distributed architecture of internet banking system

Advantages of the three tier c/s system:

  • optimal transfer of information between web server and database server
  • Communication between systems does not have to be based on Internet standards, but can use faster, lower-level communication protocols.
  • The use of middleware supports efficient database queries in SQL used to handle the retrieval of information from the database.

Simulation

The aim is for students to be able to design and explain network simulations with DHCP and DNS servers using Packet Tracer.

According to Wahana Komputer (2005:8), computer networks are classified based on their scope and reach into;

  1. Local Area Network (LAN)
  2. Metropolitan Area Network (MAN)
  3. Wide Area Network (WAN)
  4. Dynamic Host Configuration Protocol (DHCP)
  5. Domain Name Server (DNS)
  6. Procedures and Results of the Practical Work
  7. Review and Conclusion.

1. Local Area Network (LAN)

It is a network that connects several computers in a local area, usually in one building or between buildings, in a house or between boarding houses, offices, industries, universities, hospitals and other local areas. In a LAN network, data transmission speeds can reach one to 100 Mbps, even current technology can reach 1Gbps.

In general, a LAN is a communications network that has the following characteristics:

  • Local area in nature,
  • Controlled by one administration,
  • Users in a LAN are considered trustworthy,
  • Usually has high speed for data-sharing to all client computers,
  • Can connect multiple computers,
  • Can be connected to the internet,
  • Data backup is easier and faster,

2. Metropolitan Area Network (MAN)

MAN is a network that connects several computer networks in a wider area, usually used by a corporation, computer networks in one city, between campuses in a university and so on.

The special characteristics that distinguish MAN from LAN and WAN, namely.

  • The MAN network area is the middle between the LAN and WAN network areas. MAN usually has a network area between 5 to 50 km and connects computers in a city.
  • MAN (like WAN) is usually owned by several organizations. In MAN, the communication network and equipment are usually owned by a network provider that sells services to users. The services available are dependent on the MAN operator and the performance is usually predetermined.
  • MAN is a high-speed network that allows data sharing over a wide area.
  • MAN can be connected to other networks to form a WAN.

On the internet, the organization that operates using this network system is the Internet Service Provider (ISP). ISPs manage the communication cycle to individual users. They also ensure that they can monitor user/consumer usage and access services. ISPs profit from their network customers and are responsible for meeting the needs of consumers who have paid for them.

The ISP itself pays the WAN provider or Network Service Provider (NSP) for the connectivity it needs. Many ISPs are connected to other ISPs or to several other NSPs. Additional connections have rarely been problematic.

3. Wide Area Network (WAN)

It is a network that connects several WANs from several different cities or countries. WANs are usually connected via satellite. WANs have a very wide area and use communication cycles that connect intermediate nodes. Transmission speeds vary from 2 Mbps, 34 Mbps, 45 Mbps, 155 Mbps, to 625 Mbps or even more. Specific factors that affect its design and performance lie in the communication cycle, such as telephone networks, satellites or other carrier communications.

Benefits of using WAN

  • The area of ​​the WAN network can reach all parts of the world.
  • File transfers to distant locations can be sent quickly via email and FTP (File Transfer Protocol).

4. Dynamic Host Configuration Protocol (DHCP)

It is a network protocol that allows a network device to share IP Address configuration to user computers that need it. This IP Address configuration includes the IP Address itself, subnet mask, default gateway and DNS Server needed to access the internet. The device that will share the IP Address configuration is called a DHCP Server. You can build a DHCP Server using a Mikrotik router. While the computer that will request an IP Address on the DHCP Server is called a DHCP Client (Rendra Widjojo, 2013:83).

5. Domain Name Server (DNS)

Its function is to translate Domain names into a series of IP numbers. For example, when we are going to open a certain URL such as google.com, yahoo.com, facebook.com, etc. So this is where DNS works to encode (translate) from the domain name into a series of unique numbers in the form of IP, for example google.com IP Address is 208.67.219.231, this IP is what will be used by internet machines to communicate with each other such as Domain Server, Hosting Server, Proxy Server and so on.

B. Practical Steps

PC0-PC4 = IP Address DHCP
Server0 = IP Address 192.168.10.1 Netmask 255.255.255.0

1. DHCP Server Single Network


Network Topology

1.1 Open packet tracert
1.2 Prepare five PC-PTs, 1 switch and 1 Server-PT
1.3 Arrange them into a star topology as shown in Figure
1.4 Set the IP Address of the Server-PT

1.5 Set up DHCP Server configuration on Server-PT

1.6 Set the IP Address on the Client computer from static to DHCP

2 DNS Servers Single Network

2.1 Configuration of the topology using point 1
2.2 Creating a web page on Server-PT

2.3 Setting DNS server on Server-PT

2.4 Perform DNS testing via browser on PC-PT Client

Bibliography

Computer, W, 2011, Network Administration With Linux Ubuntu 11, Andi Publisher, Yogyakarta. Widjojo, R, 2013, Mikrotik Kungfu Book 1, Jasakom, Jakarta. https://indosat.net.id/knowledgebase.php?action=displayarticle&id=2  accessed March 24, 2014

6. Analysis and Results of Practical Work

Procedure

  1. Download and install the Packet Tracer application;
  2. Windows :  http://www.packettracernetwork.com/
  3. Linux : <ftp://rpmfind.net/linux/opensuse/update/12.2/i586/libopenssl1_0_0-1.0.1e-2.8.1.i586.rpm>

Analysis

1). Create 2 different networks with star topology, where network 1 (fastnet0) has 1 server and network 2 (fastnet1) has 2 servers, as shown in the image below:

DOWNLOAD SUMULATION TOPOLOGY.pkt

2). Determine the IP Address, Default Gateway and DNS Server on each existing Server, a complete explanation is in the following image, also pay attention to the color marks:

Color description: Server 1, Server2, Server3.


Server 1


Server 2


Server 3

3). Synchronize the Default Gateway of both networks on the Router, as proven in the previous practicum that for several different networks, the NetID can be the same but the HostID must be different. A full explanation can be seen in the image below:


Network 1 (Fastnet 0)


Network 2 (Fastnet 0)

4). Setting DHCP for each server, first activate the service by ensuring that the check point position is in ON mode, then input the default gateway according to the network scope and fill in the DNS Server with its IP Address, in full;


DHCP Server 1


DHCP Server 2


DHCP Server 3

5). DNS settings only on the main server, in this case study is the server on network 1 (fastnet 0), by registering the IP Address itself and the IP Address on another network, in this case study the Main Server IP is Red, the second Server IP is Blue and the third Server IP is Green, for more details see the top picture and the picture below:


Primary DNS Server

Meanwhile, for DNS settings on Server 2 and Server 3, just leave them blank.

6). The last step is to activate DHCP in the Client IP Configuration, do this step for all Clients (PCs),


Client IP Configuration

Experimental Results

a). Using PC2 to access the domain jarkom1.com (ip server1), jarkom2.com (ip server2 / different network) and jarkom3.com (ip server3 / different network) by clicking PC2 > Desktop > Web Browser;


Access the domain jarkom1.com (ip server1)


Access the jarkom2.com domain (server2 ip / different network)


Access the jarkom3.com domain (ip server3 / different network)

b). Using PC8 on Server 3 to access the domain jarkom1.com (ip server1 / different network), jarkom2.com (ip server2) and jarkom3.com (ip server3) by clicking PC8 > Desktop > Web Browser;


PC8 access server 1


PC8 access server 2


PC8 server access 3

7. Review and Conclusion

Review

  • The reason why the DNS Server is filled with the IP Address belonging to Server 1 is because Server 1 functions as the main server.
  • The Gateway Host ID on each network cannot be the same.
  • Dynamic Host Configuration Protocol (DHCP) makes it easier to configure IP Clients, because everything is automated.

Conclusion

  • Domain is a unique variable for IP addresses, so it makes it easier for someone to memorize it, rather than the actual IP form which is in the form of numbers.
  • Both can be accessed via a browser, whether it is a domain or IP Address when entered into the browser, it will display the same page, with the note that the IP domain has been registered or configured on the DNS Server, because if not, "Host Name Unresolved" will appear.

Bibliography


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