We live in an age of industrial revolution and the Internet is indispensable. Quiz everyone to live 1 day without being online . Like I can’t do it (play games) . So does everyone understand how the Internet works? TCP / IP is a commonly used transmission method for today’s Internet. But what is the pattern of TCP / IP? What is the function of each layer in the TCP / IP model? This article I will introduce basic about TCP / IP
1. TCP / IP model
TCP / IP stands for Transmission Control Protocol / Internet Protocol , a collection of information exchange protocols used to transmit and connect devices on the Internet. More specifically, TCP / IP shows us how to pack information (also known as packets), sent and received by connected computers. (Easy to understand, isn’t it? )
- The standard TCP / IP model consists of 4 layers which are superimposed:
- Level 1: Physical layer (Network Access – translation seems k right but it is the physical layer offline )
- Level 2: Network layer (Internet)
- 3rd floor: Transport floor
- Level 4: Application layer (Application).
So what is the function of these levels? Let’s find out!
2. Stratification model in TCP / IP
Looking at its name, we also know what it has to do, right? .
- It provides communication to users.
- Provides applications that allow users to exchange application data through various network services (such as web browsing, chatting, emailing, etc.).
- The data arriving here will be formatted as a byte-connected byte format, along with routing information that helps determine the correct path of a packet.
Several data exchange protocols
- FTP (File Transfer Protocol): TCP protocol that allows ASCII or binary files to be transmitted in two directions.
- TFTP (Trival File Transfer Protocol) : file transfer protocol running on UDP platform
- SMTP (Simple Mail Transfer Protocol) : the protocol used to distribute email.
- Telnet : allow remote access to configure devices.
- SNMP (Simple Network Managerment Protocol) : It is an application running on UDP platform, allowing management and monitoring of network devices remotely.
- Domain Name System (DNS) : A domain name resolution protocol used in Internet access support.
- Responsible for maintaining end-to-end communications throughout the network.
- This layer has 2 main protocols: TCP (Transmisson Control Protocol) and UDP (User Datagram Protocol)
- TCP will ensure the quality of packet transmission, but it takes a long time to fully check information from the order of data to controlling traffic congestion.
- Contrary to TCP, UDP sees a faster transfer speed but does not guarantee the quality of data being sent (ie it does not care whether the data reaches the destination or not).
I will talk more carefully about these 2 guys in the following article
Network layer (Internet)
- Handling the process of packet transmission on the network.
- The data segments will be packaged (Packets) with the size of each packet suitable to the switching network that it uses to transmit data. At this point, the packet is inserted Header section containing information of the network layer and continue to move to the next layer.
- The protocols of this layer include: IP ( Internet Protocol – a protocol widely used in all networks around the world), ICMP ( Internet Control Message Protocol ), IGMP ( Internet Group Message Protocol ).
- The IP protocol has some of the following characteristics:
- IP data is transmitted immediately if possible (best effort), without any connection establishment mechanism, no acknowledgment or flow control mechanism is used with IP, IP packets. nor numbered when exchanging on the internet …
- Each IP packet is handled independently of other IP packets.
- The IP protocol uses a hierarchical addressing mechanism, where the NetworkId part of the address is the same as the name of a road and the hostId part of the IP address will be the same as the house number of a house on that path.
- There is no mechanism for recovering lost packets on the transmission line. This is left to the upper layer assignments at the terminal hosts.
Physical layer (Network Access)
- It is a combination of Data Link layer and Physical layer in OSI model (This model you learn more offline. Its nature is similar to TCP / IP)
- Is the lowest layer in the TCP / IP model.
- Responsible for data transmission between devices in the same network. Here, the packets are framed (frames) and routed to the original specified destination.
3. How TCP / IP works
When transmitting data, the process proceeds from the upper layer to the lower layer, through which each data layer is added with control information called Header. When the data is received, the process is reversed, the data is transmitted from the bottom up and through each floor, the corresponding header will be removed and when to the top floor, the data is no longer header.
- Here, IP plays an important role, it allows packets to be sent to a designated destination, by adding navigation information (the Header) to the packets so that the packets reach the intended destination. predetermined.
- The TCP protocol plays a role of checking and ensuring the safety of each packet when passing through each station. During this process, if the TCP protocol detects that the packet is corrupted, a signal will be transmitted and require the system to send another packet.
The picture above is the data structure across the floors. In the picture people will see at each different floor the data transmitted is different
- Application layer: data are streams called streams.
- Transport layer: the unit of data sent by TCP is called the TCP segment.
- Network layer: data sent by IP to the lower layer is called IP Datagram
- Link layer: data transmitted is called a frame.
4. Advantages of the TCP / IP model
- Not under the control of any organization => we are free to use
- Highly compatible with all operating systems, computer hardware and networks => works effectively with many different systems.
- Highly scalable, routable => able to determine the most efficient path.
Above is an overview of the TPC / IP model that I have learned through my classroom textbooks . Hope you can now understand how the Internet works.
Next time I will introduce more about the TCP and UPD protocols at the transport layer because these are also two important protocols in this model.
Thanks for watching