TCP vs UDP: What is the Difference Between Both Protocols?

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?

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.

What is UDP?

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.

Difference Between TCP and 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 connectionless protocol whereas TCP is a connection-oriented protocol. In TCP, a connection is established between a sender and receiver before sending data. Here, the three way handshake is used, which involves the exchange of SYN (synchronize) and ACK (acknowledge) packets. 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

	TCP	UDP
Type	Connection-oriented	Connection-less
Speed	Slower	Faster
Error Detection & Correction	Yes	No
Reliability	Higher	Lower
Flow & Congestion Control	Yes	No
Weight	Heavyweight	Lightweight
Acknowledgement	Yes	No
Method of Transfer	Packets are delivered in order	Datagrams 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:

• Trivial File Transfer Protocol (TFTP)
• Domain Name System (DNS)
• VPN tunneling
• Voice over Internet Protocol (VoIP)
• Online games
• Media streaming

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)

Advantages of TCP

Here are some pros of TCP:

• Provides error checking and recovery mechanisms
• Support for many routing protocols
• Operates independently

Disadvantages of TCP

Here are some cons of TCP:

• Offers slower speeds than UDP
• Connections are heavyweight
• Isn’t compatible with broadcasting

Advantages of UDP

Here are some pros of UDP:

• Availability of broadcast and multicast transmissions
• Offers faster speeds than TCP
• Connections are lightweight

Disadvantages of UDP

Here are some cons of UDP:

• Doesn’t perform any error recovery
• Packets are sent out of order
• Susceptible to data loss

What are the Applications of UDP and TCP? 

User Datagram Protocol (UDP)

A connectionless transport protocol, UDP finds its applications in various scenarios where real-time communication and low latency are essential. Its applications include:

1. Real-time Streaming

UDP is commonly used for live streaming, online gaming, and video conferencing applications. 

Its low latency makes it suitable to transmit continuous data streams without extensive error checking.

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2. VoIP (Voice over Internet Protocol)

UDP can handle voice communication applications, like VoIP services, due to its low overhead and ability to have quick data delivery. 

Real-time voice transmission benefits from the simplicity and speed of UDP.

3. DNS (Domain Name System)

Although DNS can also use TCP, UDP is the preferred choice for most DNS transactions, especially for resolving common queries. The reason is that it is lightweight in transmission.

4. Broadcasting and Multicasting

UDP is suitable for scenarios where information needs to be broadcasted or multicast to multiple recipients simultaneously. 

Applications like live broadcasting and online gaming benefit from UDP’s ability to efficiently handle multicasting.

Transmission Control Protocol (TCP)

TCP, a reliable and connection-oriented protocol, is employed in scenarios where data integrity and delivery order are paramount. Its applications include:

1. Web Browsing

TCP is the backbone of the World Wide Web, ensuring reliable web page content delivery. When you access a website, your browser uses TCP to connect with the web server and fetch the data in a structured and error-checked manner.

2. File Transfer Protocol (FTP)

FTP relies on TCP for secure and accurate file transfers. The reliability of TCP ensures that files are transmitted without errors, and its connection-oriented nature ensures that the entire file is delivered in the correct order.

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3. Email Communication

SMTP (Simple Mail Transfer Protocol) and POP3/IMAP (Post Office Protocol 3/Internet Message Access Protocol) utilize TCP for sending and receiving emails. 

Reliable transmission is essential, so TCP mainly carries out email communication.

4. Remote Desktop Access

Applications like Remote Desktop Protocol (RDP) rely on TCP to provide a reliable and secure connection for remote desktop access. 

Should I Use UDP or TCP for Video Conferencing?

Both TCP and UDP play crucial roles in various aspects of communication. However, TCP is considered the preferred solution for addressing related to video conferencing.

While UDP excels in swiftly transmitting data, TCP becomes the go-to choice for video conferencing scenarios, prioritizing quality over speed. 

So, the decision remains yours.

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.

What Protocols Can You Use With a PureVPN Subscription? 

PureVPN takes the initiative to automatically select the optimal VPN protocol for you, ensuring a secure and swift connection. 

Additionally, you can manually choose their preferred VPN protocol if they wish.

1. WireGuard

WireGuard, the latest VPN protocol, aims to replace IPSec. Considered a lighter and faster alternative, it enhances open-source credentials, reducing the likelihood of security vulnerabilities. 

However, it still needs to be in development and lags in cross-platform compatibility.

2. L2TP – Layer 2 Tunneling Protocol

Lacking robust authentication, L2TP is often paired with IPSec for security. 

Despite potential firewall conflicts, it is a viable alternative to OpenVPN due to its compatibility with modern platforms and ability to bypass ISP/network restrictions.

3. SSTP – Secure Socket Tunneling Protocol

Owned by Microsoft, SSTP is exclusive to Windows, FreeBSD, and Linux. While unauditable, it is one of the most secure VPN protocols.

4. OpenVPN – Open-Source Protocol

Recognised for its high-speed performance and top-tier encryption, OpenVPN is the preferred protocol. 

It works for extensive configuration and operation on any port, enabling it to overcome ISP/network restrictions and firewalls.

5. IKEv2 – Internet Key Exchange

IKEv2 is a recent and advanced VPN protocol based on the IPSec framework. 

Developed collaboratively by Cisco and Microsoft, it excels in speed, stability, security, and ease of setup. However, it sometimes results in limited support for older platforms.

6. IPSec – Internet Protocol Security

IPSec is commonly used to secure VPNs. 

It is frequently paired with VPN protocols like IKEv2 and L2TP and offers data confidentiality and authentication. It can also function as a standalone VPN protocol.

7. SSL/TLS – Secure Socket Layer

SSL and its successor, TLS, are widely used cryptographic protocols. 

While not standalone VPN protocols, they are crucial in securing connections, as seen in HTTPS websites and VPN protocols like OpenVPN.

8. PPTP – Point-to-Point Tunneling Protocol

Offering basic encryption and lower security, PPTP prioritizes speed. Despite its support for various platforms and easy setup, it’s not recommended for situations where security is a primary concern.

9. SoftEther

Relatively new compared to other VPN protocols (excluding WireGuard), SoftEther has gained popularity for its security, stability, and speed. 

Compatible with most operating systems, including Solaris and FreeBSD, it offers features like GUI Management and RPC over HTTPS that differentiate it from OpenVPN.

FAQs

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

Is UDP or TCP better?

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!