TCP/UDP (Socket Communication)

kc@example.com (kc kim) — Fri, 08 Jul 2022 18:59:00 +0900

TCP (Transmission Control Protocol)

Provides a connection-oriented service.
Guarantees high reliability.
Establishes connections with 3-way handshaking.
Terminates connections with 4-way handshaking.
Provides data flow control and congestion control.
- Flow control: prevents receiver buffer overflow.
- Congestion control: prevents an excessive increase in the number of packets in the network.
Provides full-duplex, point-to-point service (bidirectional transmission and reception).
Used for cases where reliability is important, such as file exchange.

UDP (User Datagram Protocol)

Provides a connectionless service.
Has low reliability.
The order of data transmission can change.
Does not confirm whether data was received; there is no process like 3-way handshaking.
Has a faster transmission speed than TCP.
Mainly used for streaming, where real-time delivery is important.
Supports 1:1, 1:N, and N:M communication.

What Is Network TCP/IP?

kc@example.com (kc kim) — Tue, 10 Jan 2023 11:21:21 +0900

What Is TCP/IP?

TCP/IP is a combination of TCP (Transmission Control Protocol) and IP (Internet Protocol), and it can be considered one of the most important technical elements for supporting computer networks.

In general, “TCP/IP” is used as a collective term for the communication technologies that operate computer networks and the internet. It includes not only TCP and IP, but also various protocols such as ICMP, TCP, and HTTP. In any case, you can think of it as the set of protocols needed to send something over a network.

What Is a Protocol?

Here, a protocol means a “communication rule.” Data is transmitted together with various elements.

Data A: the data that starts first
Data B: the next data
Data C: the data after that

If the order in which data is sent is not determined in this way, it becomes impossible to know what was actually sent.

For example, if you know that data such as “recipient,” “where it came from (your own address),” and “data contents” is sent in order, the receiving side can also identify the data by recognizing it as “recipient,” “where it came from (your own address),” and “data contents.”

That is why protocols are essential.

In short, you can think of TCP/IP as the communication rules for a network.

Through What Interaction Is Data Transmitted?

For example, suppose you are viewing a site on the internet. A request like the following is sent through the network.

The browser creates a request message.
The operating system’s TCP/IP processing software passes the data to a place called the transport layer.
The TCP protocol in the transport layer attaches a TCP header, meaning that this kind of data is added to the beginning of the data.
Next, the data is sent to a place called the network layer, where an IP header, containing data such as the destination, is attached.
Then header information such as a MAC header is added on top of that, and the data is sent from the LAN adapter.

This is difficult. It may be a little hard to understand, but you can think of it as sending data after attaching various pieces of information to the beginning of the data as needed.