OSI LAYER MODEL: Data Transfer From Student's Computer to Ulearn System Server Which is in the UTeM IT Center

What is OSI Model?

Open Systems Interconnection (OSI) Model is a model which describe seven layers of communication over a network between computer systems. It was the first standard modal for network communications, adopted by all major computer and telecommunication companies in the early 1980s.

The modern internet is now based on the simpler TCP/IP Model, not on OSI Model. However, the OSI Model is still widely used because it can help to visualize and communicate the operation of networks. It also helps in the isolation and troubleshooting of networking problems.

OSI Layer Model

Responsibilities of Each Layer:

Application Layer

To allow access to network resource.

Presentation Layer

To translate, encrypt and compress data.

Session Layer

To establish, manage and terminate session.

Transport Layer

To provide reliable process-to-process message delivery and error recovery.

Network Layer

To move packets from source to destination and to provide internetworking.

Data Link Layer

To organize bit into frames and to provide hop-to-hop delivery

Physical Layer

To transmit bits over a medium and to provide mechanical and electrical specifications.

From Student's Computer:

Application Layer

Students as the user can remote log in by typing in their student email address and password. Normally, they will upload file or post forum to the Ulearn page. All of these are the data which will be processed in the next layer.

Presentation Layer

For this layer, the information of student (email address and password) will send to the Ulearn server in IT center . Then the Ulerarn system will converts outgoing data from one presentation format to another.

Session Layer

At Session Layer open the manages, and closes conversations between student's computer and Ulearn application synchronizes the interaction between student' computer and ulearn server.

Transport Layer

The transport layer receives the data from the upper layer and performs segmentation. The source and destination port numbers will include in the header file of the data before forwarding it to the network layer. Typically, the data were transported by Transmission Control Protocol (TCP). Since TCP has built-in systems to check for errors and guarantee that data will be delivered in the order it was sent, making it the perfect protocol for transferring information like still images, data files, and web pages.

Network Layer

The network layer will use logical addresses to communicate from the student’s computer to the Ulearn System server in the UTeM IT Center in different networks. Furthermore, it adds the IP address of the sender (Student) and the receiver(IT Center) in each packet so that each sent packet can reach its designated destination.

Data Link Layer

The encapsulated information from the Network Layer is received by the data link layer and then converted into a digital signal, pass it to physical layer.

Physical Layer

This layer receives digital signals from the Data Link layer, converts them to analog signals, and then putting them into the physical medium.

To Ulearn System Server:

Physical Layer

UTeM IT Center will get the signal received, convert it into digital signals ( 0s and 1s ) and send them to the Data Link layer for further processing.

Data Link Layer

In this layer will organise digital signal into frames and correct faults at the physical layer to ensure that data flow is error-free than transmitting frames to the network layer.

Network Layer

The network layer is not needed when both the systems are connected to the same link. It then reassembles the data packets into segments for the upper layer.

Transport Layer

In this layer, the transport layer will perform the reassembly and sequencing of data. It reads the port number of the data from the header file and then directs it toward the proper application.

Session Layer

In this session layer The ulearn server in IT center performs name recognition and the functions such as security, needed to allow student's computer to communicate over the network, also provides error handling.

Presentation Layer

For this Ulearn Server in UTeM IT Center will receive all the information and data from

student. Then the Ulearn system will execute the data encryption and text compression.

Application Layer

The Ulearn Server in UTeM IT Center will receive all of the data from the presentation layer. When the data received, it means that the data transfer from student's computer to the server is successful and completed.

Subnetting Calculation

In this section, you are expecting to show the calculation on how to identify the IP address that was assigned for the Ulearn System Server based on the information given in the project scenario. Explain the concept and show the calculation to identify the IP address.

In term of private addressing scheme, UTeM network is using Class C private addressing scheme which is 192.168.1.0/24. At UTeM, there are 8 different faculty. Hence, the network address was segregated by using subnetting concept. Each faculty member is given their network address. Assign IT Center as another subnet with their network address. From this network address, assigned as the 5^th available address as the address of the Ulearn System Server.

Assume that IT Center is being assigned as the 5^th available subnet as their network address.

For UTeM network, it uses Class C private addressing scheme: 192.168.1.0/24

Subnetting to 8 faculties

So, in this case, we will use 2³as our number of host bits borrowed as 8 fulfils our requirement.

3 bits need to be borrowed from the Host

Old	192	168	1	0	/24
New	192	168	1	NNNHHHHH	/27

N = network bit , H = host bit

255.255.255.224 is the new subnet mask. We get 224 by adding 128, 64, and 32 since we borrow 3 bits from the host.

Possible Number of Hosts per Subnets

To calculate the number of possible hosts per subnet, use the formula 2^n -2, where h equals the number of host bits. Two addresses must be subtracted because of the network address and the broadcast address.

Determine the number of remaining host bits based on the class of address and the number of host bits borrowed.

New Netwok Number

192.168.1.0/27

New Subnet Mask

255.255.255.224

Class Type

Number of Host Bits Available

Number of Host Bits Borrowed

Number of Host Bits Remaining (n)

8-3 =5

Number of Hosts per Subnet

= 2ⁿ– 2

= 2⁵-2

=32 -2

=30

New Prefix

/27

Number of Usable Host per Subnet

= 2³- 2

=30

IP table

Subnet number	Network ID	Host ID Range	Broadcast Address
0	192.168.1.0/27	192.168.1.1/27 To 192.168.1.30/27	192.168.1.31/27
1	192.168.1.32/27	192.168.1.33/27 To 192.168.1.62/27	192.168.1.63/27
2	192.168.1.64/27	192.168.1.65/27 To 192.168.1.94/27	192.168.1.95/27
3	192.168.1.96/27	192.168.1.97/27 To 192.168.1.126/27	192.168.1.127/27
4	192.168.1.128/27	192.168.1.129/27 To 192.168.1.158/27	192.168.1.159/27
5	192.168.1.160/27	192.168.1.161/27 To 192.168.1.190/27	192.168.1.191/27
6	192.168.1.192/27	192.168.1.193/27 To 192.168.1.222/27	192.168.1.223/27
7	192.168.1.224/27	192.168.1.225/27 To 192.168.1.254/27	192.168.1.255/27

Based on the table above, at the 5^th available subnet and 5^th available address. We are sure that the ULearn System server IP address is 192.168.1.166. We do not start from 192.168.1.161 because it will be set up as router IP Address for that subnet and become default gateway. So, it should start from 192.168.1.162 and so on.

TCP/IP Setting Manual

In this section, you are assumed have correctly identified the IP address for the Ulearn System Server. Therefore, you must produce a manual on how to configure the IP address on the server. You can use any operating system to demonstrate this task. The explanation should be supported with the screenshot and appropriate explanation.

1. Press wins + R, type Control Panel and then press ok to open it

2. After opening the Control Panel, go to Network and Internet. Then click it to open.

3. After opening the Network and Internet, click Network and Sharing Center to open.

4. After opening the Network and Sharing Center , your internet connection will appear. You may use either Wi-Fi or Ethernet. In this example, I am using hotspot as my Wi-Fi which is HUAWEI nova 4e. Then click the Wi-Fi status.

5. Hence, click Properties.

6. In this activity, we would like to configure the IP address. Thus, double-click Internet Protocol Version 4 (TCP/IPV4) to open its Properties

7. Internet Protocol Version 4 (TCP/IPV4) Properties will be opened. This is where e will configure the IP address. Commonly, we will use DHCP server, and the IP address will be obtained automatically.

8. In order to configure the IP address, we change the setting from Obtain an IP address automatically to Use the following IP address. Next, we fill in the IP address for ULearn System Server that we get from Subnetting Calculation, which is 192.168.1.166 .

9. The Subnet Mask will be automatically filled based on the IP address class. In this situation, The IP address is class C, that’s why the subnet mask will be 255.255.255.0

10. Default Gateway is an intermediary between the local network and the world wide web. The host address usually will be the same as the IP address but different in the 4^th octet, and that number will always be the first range.So, the Default Gateway is 192.168.1.161.

11. For Preferred DNS Server, commonly, we will use the same address in Default Gateway, which is 192.168.1.161. While the Alternate DNS Server is 8.8.8.8 since we use the Google DNS server.

12. After completing the requirements, click Validate setting upon exit, then click OK button

13. After exit, a Windows Network Diagnostics pop-up box will appear to check whether there is no problem with the new IP address configuration or not. If no, press the close button.

14. In a nutshell, you may test your internet connection. If you can access any website, its means the configuration of IP address was successful.

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