TCP vs. UDP: What is the difference between TCP and UDP?

TCP vs. UDP: Both are used for sending data across devices. The biggest difference between TCP and UDP lies in the manner in which the data is transmitted. Where TCP establishes a connection between the communicating devices before transmitting the data, UDP sends the data without building a connection between devices.

Key Differences & Benefits

ConnectionEstablishes a connection to send data / Does not
SpeedSlow / Fast
Data ReliabilityEnsures the delivery of data packets / Does not
BroadcastingSuitable / Not Suitable

Read also: Modem vs. Router: What is the difference between Modem vs. Router?

Considering TCP vs. UDP definitions for understanding

What is the TCP?

Transmission Control Protocol (TCP) is a connection-oriented data transfer protocol that facilitates communication between different devices in a network.

What is UDP?

User Datagram Protocol (UDP) is a datagram-oriented data transfer protocol that facilitates communication between different devices in a network.

Looking at the similarities between TCP and UDP

  • Both TCP and UDP transfer data packets over the internet.
  • Both these protocols are built over the IP protocol.
  • Both perform error-checking before sending the data.

Listing the Pros and Cons of UDP and TCP

TCP Pros and Cons

Pros of TCP
  • It transmits the data packets in a particular sequence.
  • Data retransmission is possible if any packet is lost.
  • Data delivery is guaranteed.
Cons of TCP
  • Data transmission is slower than UDP.
  • Data might not be sent immediately.
  • Real-time data transmission is difficult.

UDP Pros and Cons

Pros of UDP
  • It has smaller packet sizes.
  • Data transmission is faster.
  • You generally have more control over the time when the data is sent.
  • Real-time data transfer works extremely well.
Cons of UDP
  • It does not deliver data packets in a sequence.
  • It is impossible to retransmit the data packets.
  • Data delivery is not guaranteed.

UDP vs. TCP VPN: Understanding the compatibility of both the protocols with VPN services

The “OpenVPN TCP vs. UDP” compatibility is important to discuss as VPN adds a layer of privacy and security to your network. Both TCP and UDP work well with OpenVPN and can be used for varied purposes.

DNS TCP or UDP: Does DNS use TCP or UDP?

DNS uses UDP for faster transmission of data. DNS requests are tiny and can fit pretty well within the UDP segments. Also, when the data size is larger than 512 bytes, either larger UDP packets are used, or TCP is utilized for efficient transmission depending on the availability of Extension mechanisms for DNS (EDNS).

When is TCP used over UDP?

TCP is used when an application wants guaranteed message delivery. The ‘FTP TCP or UDP’ and ‘SSH TCP or UDP’ protocol discussions lead to the same answer i.e. TCP. Both Secure Shell (SSH) and File Transfer Protocol (FTP) use TCP to ensure correct and complete data packets delivery.

How is SCTP different from TCP and UDP?

Stream Control Transmission Protocol (SCTP) is different from TCP since it involves message-oriented data transfer instead of a byte-oriented transmission. It is different from UDP since it is a connection-oriented protocol.

Where are TCP and UDP used?

TCP and UDP are used for sending data packets over the internet. TCP is used by FTP, HTTP, HTTPS, SMTP, and Telnet. UDP, on the other hand, is used by VoIP, DNS, SNMP, TFTP, DHCP, and RIP. Also, for carrying out real-time communications, UDP is used while TCP is used where transmission of all the data packets is essential.

Does Netflix use TCP or UDP?

Netflix uses TCP for streaming videos over HTTP and web browsers since TCP can be used for efficient data transmission in case of non-real-time communications.

Is TCP or UDP faster?

UDP is faster than TCP since it does not establish a connection or perform an in-depth error-checking mechanism before delivering the data.

Is TCP or UDP safer?

TCP is safer than UDP since it carries Acknowledgement (ACK) and Sequence (SEQ) numbers that make data injection attacks difficult.

What are the 6 TCP flags?

Different TCP flags serve various purposes while transmitting data packets over the internet. The 6 TCP flags are:

  1. Urgent Pointer (URG)
  2. Acknowledgment (ACK)
  3. Push (PSH)
  4. Reset (RST)
  5. Synchronization (SYN)
  6. Finish (FIN)

What protocols would use UDP, not TCP, and why?

  • A Domain Name System (DNS) protocol uses UDP because of its fast speed. DNS requests are tiny and can fit pretty well within the UDP segments. 
  • Dynamic Host Configuration Protocol (DHCP) also uses UDP because of the lack of IP addresses’ availability at both ends.

Is Youtube a TCP or UDP? 

Youtube uses TCP since it does not stream videos in real-time. TCP allows you to fetch the videos and buffer them. You can also adjust the video quality and pause, rewind, and replay the Youtube content because of TCP. 

What is the difference between TCP and UDP?

ConnectionIt establishes a connection to send data packets over the internet. It does not establish a connection for transmitting data packets.
ReliabilityIt ensures the delivery of data packets.It doesn’t ensure the delivery of data packets.
Error checkingIt performs extensive error checking.It performs basic error checking.
RetransmissionsIt retransmits the data packets if they are lost on the way.Data retransmission is impossible.
Data sequencingIt delivers data packets in a definite sequence.It doesn’t offer data sequencing.
SpeedData transmission is comparatively slow.It performs faster transmission of data.
Header sizeIts header size varies between 20 to 80 bytes.Its header size is 8 bytes.
Data interfaceIt performs byte-oriented data transmission.It performs message-oriented data transmission.
Real-time data transferIt is not suitable for real-time data transfers.It is suitable for real-time data transfers.
Internet loadIt is a heavyweight protocol as it needs multiple packets to set up a connection.It is lightweight as it doesn’t set up a connection for data transfer.
Data quantityIt can easily transmit small to moderate amounts of data.It is suitable for small to enormous amounts of data.
BroadcastingIt is not suitable for broadcasting.It is suitable for broadcasting.

Comparison Chart

TCP vs. UDP: Discover the Key Differences, Similarities, Pros & Cons, and finally, define which is better.

Comparison Video


Which is better: UDP or TCP?

The answer to this question depends on your current requirements. If you want a reliable and stable protocol that transmits every bit of data without losing it, go for TCP. If, however, you need the faster and constant transmission of data, prefer UDP over TCP. Also, choose UDP for your real-time communication and broadcasting needs.


Author & Researcher @ Difference 101 Master in Philosophy & Data Analysis, Sorbonne Université (Graduated 2011) Lived in New York City

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