Feature | TCP (Transmission Control Protocol) | UDP (User Datagram Protocol) |
Connection-oriented | Yes | No |
Reliability | High (guaranteed delivery) | Low (no guaranteed delivery) |
Error checking | Yes (retransmits lost packets) | No (assumes no errors) |
Ordering | Yes (packets delivered in order) | No (packets may arrive out of order) |
Speed | Slower (overhead for connection & error checking) | Faster (smaller header size, no overhead) |
Header size | Variable (20-60 bytes) | Fixed (8 bytes) |
Data transfer | Byte stream | Message stream |
Broadcasting | No | Yes |
Congestion control | Yes (avoids overwhelming network) | No |
Typical uses | Web browsing, file transfer, email | Online gaming, VoIP, video streaming, DNS |
Connection-oriented: TCP is connection-oriented, meaning it requires a connection to be established before data can be sent. UDP is connectionless, so data is sent without setting up a connection.
Reliability: TCP provides high reliability with mechanisms for guaranteed delivery, while UDP offers low reliability and does not guarantee message delivery.
Error checking: TCP includes error checking and will retransmit lost packets, ensuring data integrity. UDP performs minimal error checking and does not retransmit lost packets, assuming there are no errors during transmission.
Ordering: TCP ensures that packets are delivered in the order they were sent. UDP does not guarantee ordering, and packets may arrive out of sequence.
Speed: TCP is generally slower due to the overhead involved in establishing connections, managing errors, and ensuring packet order. UDP is faster because it has a smaller header size and lacks the overhead associated with connection management and error correction.
Header size: TCP headers are variable in length, ranging from 20 to 60 bytes, depending on the options used. UDP headers are always fixed at 8 bytes.
Data transfer: TCP uses a byte stream for data transfer, where data is sent as a continuous flow. UDP uses a message stream approach, sending data in distinct packets.
Broadcasting: TCP does not support broadcasting capabilities. UDP can support broadcasting, allowing messages to be sent to multiple recipients simultaneously.
Congestion control: TCP includes congestion control mechanisms to avoid overwhelming the network, which adjusts the data transfer rate based on network conditions. UDP lacks these mechanisms, making it less suitable for environments where network congestion is a concern.
Typical uses: TCP is used for applications where data integrity and order are critical, such as web browsing, file transfers, and email. UDP is preferred for applications where speed and low latency are more important than reliability, such as online gaming, VoIP, video streaming, and DNS.