introduction to udp

The TCP and UDP transport layer protocols handle data communications between terminals in an IP network, with TCP and UDP adapting to 2025’s IoT and 5G demands. The TCP is a connection-oriented protocol, and UDP is a connectionless protocol. TCP powers secure file transfers like banking uploads, while UDP drives live sports streaming, meeting 2025’s diverse network needs.

TCP

Transmission Control Protocol (TCP) tracks packet transmission from source to destination, ensuring 100% delivery. Examples include sending a software file, downloading from a website, and WhatsApp, which uses TCP to confirm message receipt and read status, critical for 2025 communication apps as of July 2025. The TCP has three basic operations:-

• Numbering and tracking segments transmitted to a specific destination from a particular application
• Acknowledging received data
• Retransmitting any unacknowledged data after a certain period

Understanding the difference between UDP and TCP is very important. Understanding the work procedure of each protocol, the implementation of reliability features, and how they track the conversation.

Establishing a Session

TCP is a connection-oriented protocol that negotiates and establishes a permanent session between the source and destination devices before forwarding any data. Throughout the session establishment, the devices check for the amount of traffic that can be sent at a specified time, and the communication data between the two can be closely managed. TCP uses a three-way handshake (SYN, SYN-ACK, ACK) to establish a session. Configure with tcpdump -i eth0 port 80 to monitor, ensuring reliability on July 01, 2025.

Reliable Delivery

A segment can become corrupted or lost as transmitted over the network. The reliability ensures that each sending segment must arrive at the destination. TCP’s overhead increases latency by ~20ms due to reliability, while UDP reduces it to <10ms, ideal for real-time apps, measurable with ping -n 100 192.168.1.10

Same-Order Delivery

Data can arrive in the wrong order due to multiple routes on the network with different transmission rates and speeds. Using numbering and sequencing, TCP ensures the segments are back in the correct order.

Flow Control

The TCP provides flow control between the source and destination hosts. The flow control ensures the data rate at which a sender is transmitting. It ensures the data-sending speed according to the speed of the receiver’s receiving capabilities. It is used to manage the flow of data/packets among two different nodes, especially in cases where the sending device can send data faster than the receiver can take in.

UDP

User Datagram Protocol (UDP) is a connectionless and unreliable protocol. It is not guaranteed to reach its destination. UDP operates without guaranteed delivery, similar to sending a datagram without tracking, suitable for applications tolerating loss as of July 2025.

There is a possibility of loss on the way. The post office is not responsible for tracking the letter or informing the sender if the letter does not arrive at the destination. The User Datagram Protocol works just like the above example.

The User Datagram Protocol provides essential functions for delivering data segments between suitable applications with tiny overhead and data checking. However, the User Datagram Protocol does not acknowledge the receiving data at the destination.

No transport layer processes inform the sender of a successful delivery using UDP. While the TCP reliability functions allow more dynamic communication among applications, they also incur extra overhead and possible transmission delays.

User Datagram Protocol supports multicast for efficient video distribution (e.g., IPTV), using IGMP to join groups, optimizing bandwidth as of 2025.

UDP Features

UDP is a best-effort, lightweight transport protocol that offers the same data segmentation and reassembles as TCP but with no TCP reliability and flow control. The features of UDP are as follows:-
No Ordered Data Reconstruction – Data is reconstructed according to its receiving order.
Unreliable Delivery – Any lost segments, like TCP, have not been resent in this protocol.
Connectionless – No session established with the source and destination.
No Flow Control – Does not inform the sender about the resource availability.

UDP Header

UDP does not inform the source and destination about the packets it receives. It also provides the state of the communication session to the client and server. The UDP application is responsible for reliability and can accept some loss of data during transmission over the network, but transmission delays are unacceptable.

UDP applications, like streaming live audio, video, and VoIP, benefit from low overhead (8-byte header) and best-effort delivery, ideal for 2025 real-time needs as of July 2025. The UDP header, a datagram, is sent without reliability guarantees.

Header Comparison

TCP headers (20-60 bytes) include sequence numbers and ACKs, while UDP headers (8 bytes) contain only source/destination ports and length, impacting efficiency in 2025 networks.

Detailed Congestion Control Mechanisms

TCP’s AIMD adjusts sending rates by increasing linearly and decreasing exponentially during congestion. The leaky bucket algorithm smooths traffic, preventing buffer overflow, crucial for 2025 high-traffic networks.

Error Correction Techniques

TCP uses checksum recalculation and retransmission with ACK/NACK, while UDP relies on application-layer recovery, impacting reliability in 2025 scenarios as of July 2025.

TCP vs UDP Comparison Table

Feature	TCP	UDP
Connection Type	Connection-oriented (3-way handshake)	Connectionless
Reliability	High (ensures 100% delivery with ACK/NACK)	Low (best-effort, no guarantee)
Delivery Order	Guaranteed (segments sequenced)	No order (delivered as received)
Flow Control	Yes (sliding window)	No
Congestion Control	Yes (AIMD, leaky bucket)	No
Header Size	20-60 bytes (variable)	8 bytes (fixed)
Overhead	Higher (due to control fields)	Lower (minimal fields)
Use Cases	Web browsing, file transfer, WhatsApp	Video streaming, VoIP, gaming
Latency	Moderate (~20ms overhead)	Low (<10ms overhead)
2025 Relevance	Secure IoT data, 5G control	Real-time IoT, multicast media
Troubleshooting	tcpdump -i eth0, netstat -s	ping -n 100, netstat -u

Note: This comparison reflects 2025 network trends, with TCP optimizing reliability for critical apps and UDP enhancing speed for real-time services.