TCP vs UDP

TCP vs UDP: Everything You Need to Know

TCP and UDP are two commonly used protocols that netizens interact with on a daily basis that determine how data is transferred over the Internet. While they’re similar in many ways, their differences make them useful for different purposes.

In this TCP vs UDP comparison, we’ll go over what these protocols are, the main differences between them, as well as some examples of their uses:

What is TCP and UDP?

TCP, or Transmission Control Protocol, is a connection-oriented protocol that devices use to communicate on the Internet. It’s one of the main protocols in the TCP/IP protocol suite and provides error detection and correction. Furthermore, TCP guarantees reliable delivery of data and ensures that packets will arrive in the same order they were sent.

UDP, or User Datagram Protocol, is a connection less protocol that functions much like TCP but without error detection and correction services. Instead, packets are continuously sent to the recipient whether they have been received or not. This allows for devices to communicate with one another more quickly and with less overhead.

OpenVPN over TCP vs UDP

Many VPN providers support OpenVPN in their apps and allow users to select between the TCP and UDP protocol. It’s important to note that neither of them are superior to the other and the difference isn’t even noticeable to most end users. Generally, UDP offers better speeds, but it can vary on a scenario-by-scenario basis.

In some cases, either one of the protocols might be needed to circumvent a firewall. Both TCP and UDP are capable of running on different ports. However, since OpenVPN uses UDP port 1194 by default, it’s common for firewalls to blacklist it. If your OpenVPN connection is blocked, your best bet is to switch to TCP, which is more NAT and firewall-friendly.

TCP vs UDP – Differences

TCP vs UDP

Now, let’s take a look at some key differences between TCP and UDP:

Speed

UDP is faster than TCP because it has less to do. TCP not only has to establish a connection but also handle error control and guarantee that files arrive in order. UDP, on the other hand, doesn’t guarantee delivery of transferred packets and just sends data without establishing a connection.

Flow and Congestion Control

TCP’s flow and congestion control mechanism ensures that a sender doesn’t overwhelm a receiver by transmitting too much data too quickly. UDP doesn’t offer flow and congestion control as packets are received in a continuous sequence or they’re dropped.

Connection-Oriented & Connectionless

As stated earlier, UDP is a connection     less protocol whereas TCP is a connection-oriented protocol. In TCP, a connection is established between a sender and receiver before sending data. When it comes to UDP, though, it doesn’t require an explicit connection to send data.

Reliability

TCP is known for being reliable. When you send data via TCP, it’s guaranteed to arrive at your intended destination without errors. Even if data is corrupted or lost in transit, it will recover and resend it. TCP also tracks if packets go missing or are in the wrong order.

UDP, on the contrary, is an unreliable protocol and doesn’t guarantee data delivery. Due to this, datagrams might become lost or corrupt during transit. Moreover, UDP doesn’t track packets between the sender and receiver.

Ordering

With TCP, ordering and sequencing is done to ensure packets are delivered in the same order in which they were sent. UDP, however, sends datagrams in any random order.

TCP vs UDP Comparison Table

TCPUDP

Type
 
Connection-orientedConnection-less

Speed
 
SlowerFaster

Error Detection & Correction
 
YesNo

Reliability
 
HigherLower

Flow & Congestion Control
 
YesNo

Weight
 
HeavyweightLightweight

Acknowledgement
 
YesNo

Method of Transfer
 
Packets are delivered in orderDatagrams are delivered in a continuous stream

When to Use TCP vs UDP?

UDP is well suited for applications where efficiency and speed is more critical than reliability. Some examples include:

TCP is well suited for applications where reliability is a bigger concern than timing. Some examples include:

  • Email (POP, SMTP, and IMAP)
  • Secure Shell (SSH)
  • Web browsing (HTTP and HTTPS)
  • File Transfer Protocol (FTP)

Which Protocol Does PureVPN Use?

PureVPN wants to provide its users with a safe and reliable browsing experience. That’s why we use the TCP protocol by default. We recommend you give the TCP protocol a try first and only make the switch to UDP if you experience any issues or wish to engage in downloading and streaming.

Frequently Asked Questions

The following are some questions people ask about TCP and UDP protocols:

Is TCP Better Than UDP?

To be fair, neither one is particularly better than the other. Both TCP and UDP are suitable for different purposes. If speed is of utmost significance to you, then you should use UDP. If data integrity is your main priority, then you should use TCP.

Is TCP or UDP Better for Streaming?

As far as streaming (video and audio) is concerned, UDP is the far better protocol due to faster speeds and low overhead. In fact, most streaming applications use UDP rather than TCP because of this very reason.

Should I Use TCP or UDP for VPN?

Once again, it depends on what exactly your needs are. OpenVPN over UDP is typically preferred for bandwidth-intensive activities like streaming and downloading. On the flip side, OpenVPN over TCP is excellent for circumventing firewalls and geo-blocking.

Wrapping Things Up

Now that you understand the differences between TCP and UDP, you’ll be able to make sound decisions when setting up your router, configuring a firewall, or choosing a VPN protocol.

If you have any questions or confusions about TCP and UDP, feel free to voice them via the comments section below. We’ll get back to you as soon as we can!

Haris Shahid Haris Shahid has a genuine passion in covering the latest happenings in the cyber security, privacy, and digital landscape. He likes getting out and about, but mostly ends up spending too much of his time behind a computer keyboard. He tweets at @harisshahid01

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