What Is The Main Difference Between TCP And UDP

While terms are used in networking, many users can often see TCP and UDP scattered all over the place.

You could be setting up a router, installing a torrent client, or even as much as learning how to increase your gaming advantage. TCP and UDP affect all these things.

Before setting up devices, installing a VPN, or improving your gaming speeds, it is handy to know a little more about what TCP and UDP do and how they can affect your experience online.

By the end of this guide, you’ll understand a bit more than TCP is connection-oriented and UDP is a connectionless internet protocol, and they both work at the transport layer of the TCP/IP stack. (Learn What is a Proxy Server)

Transmission Control Protocol TCP

What is TCP?

Transmission Control Protocol (TCP) is the connection-oriented protocol used for communication across networks and the internet.

It is a primary protocol in TCP/IP networks where TCP/ IP protocol carries out error-checking and guarantees delivery of data. Packets are sequenced to be delivered in sending order.

What is UDP?

User Datagram Protocol (UDP) is a connectionless protocol, which works the same as TCP, yet it doesn’t carry out any error-checking or recovery services.

UDP sends datagrams to a destination if they receive them or not.

What is the Difference Between OpenVPN TCP and UDP?

If you want to use a VPN and ask is the UDP/ TCP protocols are compatible with your VPN, then yes, they will work with most VPN services that use OpenVPN on the transport layer.

OpenVPN runs using both of these network protocols, and both of them deliver privacy and security. The change comes depending on what you’re using your VPN for.

TCP (Transmission control protocol) is the most reliable, and you could think that it is always the best option to make sure a connection is established. However, there are times UDP may be a better selection.

UDP (user datagram protocol) is an excellent option for gaming, streaming, or using VoIP services. You can suffer a loss of a packet of two, and it doesn’t affect your experience.

If you used TCP for any of these, you could find an increase in lag, jitter, and buffering because of delivery checking and packet loss. OpenVPN via TCP is best suited for static use like sending an email, browsing, and transferring files.

TCP stands for transmission control protocol, and UDP, meaning stands for user datagram protocol. TCP protocol works slower out of the two, and UDP is faster when sending packets over the internet. (Learn What Is The Most Common Network Topology)

Difference Between TCP and UDP

What is the Major Difference Between TCP and UDP Packets Quizlet?

Here you can find the main differences between TCP vs. UDP protocol and how it can affect back and forth communication.

TCP (Transmission Control Protocol)UDP (User Datagram Protocol)
DefinitionCommunications protocol where data is transmitted between systems on any network once it can establish a connection.

Data can be sent in packets and includes error-checking to guarantee delivery and preserve order of data packets.
It is the same as the TCP protocol, except this doesn’t guarantee the error-checking and data recovery.
If you use this protocol, the data will be sent continuously, irrespective of the issues in the receiving end.
DesignTCP is slower as it is a connection-oriented protocol.
Header size of TCP is 20 bytes
UDP is a connectionless protocol.
Header size of UDP is 8 bytes
ReliabilityTCP offers error checking and guarantees data delivery. This makes TCP vs. UDP more reliable.UDP provides basic error checking with a checksum. The delivery of data cannot be guaranteed.
Data TransmissionTCP data is transmitted in sequences, or it carries out, flow control, meaning packets arrive in-order at the destination.UDP protocol has no sequencing and error correction; thus, any order needs managing by the application layer.
PerformanceTCP is heavy-weight protocol, compared to UDP, and thus slower and less efficient in performance than UDP.UDP works faster, more efficient than TCP, yet not as reliable.
RetransmissionTCP provides retransmission of data packets if they are lost.There is no packet retransmission with UDP.

What is the Use of TCP and UDP?

Before looking at usage scenarios, here’s a quick UDP vs. TCP breakdown.

Connection and Connectionless

TCP – A connection-oriented protocol where TCP establishes a connection between sender and receiver before any data will be sent.

UDP – A connectionless protocol and UDP doesn’t establish a connection before sending any data.


TCP is reliable where data sent with the TCP protocol is guaranteed delivery.

If data is lost during transmission, it will resend it. TCP also checks packets for errors and tracks packets, so the data isn’t lost or corrupted.

UDP is unreliable, as there is no guaranteed delivery, and a datagram packet can be corrupted in transit.

Flow control

Packets sent with TCP use flow control to ensure a sender won’t be inundated with too many packets.

TCP stores data in send buffers and receives data in receive buffers.

Once the application is ready, it reads data from the receive buffer.

UDP doesn’t provide flow control. With UDP, packets arrive continuously, or they are dropped.


TCP vs. UDP is slower because of the extra work. You don’t choose whether to use TCP or UDP as this is governed by the app in many scenarios.

In the case of a VPN, the software decides to use TCP/ UDP depending on the use and the device.

With a VPN, with the extra encryption, even with UDP, you won’t have packets corrupted by a third party as they won’t see them.

Here are the most commonly used areas for using either internet protocol, be it TCP/ UDP on a network or the internet. (Read SBS On Demand Not Working On Smart TV)

TCP suits these applications:

  • World Wide Web (HTTP, HTTPS)
  • Secure Shell (SSH)
  • Data Transfer with File Transfer Protocol (FTP)
  • Email (SMTP, IMAP/POP)

Here, you can see it is widely used for applications that require high levels of reliability where timing isn’t so much of a concern.

UDP suits these applications

  • Video streaming
  • Online games
  • Live broadcasts
  • Domain Name System (DNS)
  • Voice over Internet Protocol (VoIP)
  • Trivial File Transfer Protocol (TFTP)
  • VPN tunnelling

The communication data UDP transmits will be noticeable in the form of dropped frames in streaming or playing games. When using a web browser, you’ll hardly ever notice unless a page doesn’t load when using UDP.

A VPN can help here as all communication travels via a direct route rather than numerous around the internet until it reaches its destination.

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What Is The Main Difference Between TCP And UDP