The Case for Choosing Between TCP and UDP for Data Transmission

Data has become essential to our daily lives; people transmit data from one point to another for several reasons, which include facilitating communication and sharing of information between individuals and organizations; two of the common fundamental ways people transmit data are TCP and UDP. Data transmission effectively enhances point-to-point, point-to-multipoint, and multipoint-to-multipoint communication for devices. 

The debate of TCP vs. UDP has been on for a long time and will continue; the choice of which you choose to use depends on what you want to achieve.

What Is TCP?

Transmission Control Protocol (TCP) is a reliable, connection-oriented protocol that you can use to transmit data over a network. It ensures that data is delivered error-free, in sequence, and without loss or duplication. 

TCP transfers your data over the internet from your device to a web server and works perfectly for applications that require high reliability, such as email, file transfer, chatting with friends on Skype, watching online videos, and web browsing. Due to being connection-based, TCP reliably enhances and maintains a connection between the receiver and sender while transferring data. 

TCP has become the most popular network because it ensures Data arrives completely intact.

How Does TCP Work?

TCP usually sends small packets of data through the internet that get reassembled when they arrive at the receiver’s destination. In practice, TCP executes data transmission by assigning each data packet a sequence number and unique identifier. 

The sequence number and unique identifier enable the receiver to identify which packet was received and which will arrive subsequently. The receiver sends an acknowledgment to the sender on the sequential and orderly arrival of the data packet, which prompts the sender to send another packet.

If the recipient does not acknowledge receiving the packet, it may indicate that a packet is lost or sent in the wrong sequence, and a resend is necessary. Sending data in sequence eliminates congestion and enables flow control, making it easy to correct errors.

The back-and-forth communication between the two parties necessitates a long period to establish a connection and exchange data; the time you spend enables the data you send over TCP to reach the recipient safely.

What Is UDP?

UDP (User Datagram Protocol) is a connectionless protocol (doesn’t establish a prior connection between two parties) that provides an unreliable but fast (especially where speed is crucial, such as in gaming and streaming) and more straightforward way of transferring data over a network, containing a packet of data, the source, destination addresses, and the data payload. A UDP user can experience packet loss due to network congestion, errors, latency, bandwidth issues, or other factors.

How Does UDP Work?

UDP can transmit data as TCP without the mandatory unique identifiers and sequential numbers. It sends data in a stream and only has a substantiation to corroborate data uncorrupted arrival. 

UDP doesn’t care about lost packets or fix errors; it’s highly error-prone but transmits data much faster than TCP. The inability to correct mistakes in identifiers and number sequence or the difficulty in setting up a firewall allowing some UDP communications and blocking the rest doesn’t mean that UDP connections are left entirely unprotected. 

While it’s easier to secure TCP than UDP, UDP users can deploy the virtual private network (VPN) and proxies for particular apps or enable a protective tunnel connecting the remote user and the organization’s internal network.

What Are the Fundamental Differences Between TCP and UDP?

Fundamentally, TCP and UDP are the most commonly used protocols for transmitting data over a network. The fundamental difference between TCP and UDP lies in how they enhance a connection and ensure reliable data transfer. 

TCP is a connection-oriented protocol that establishes a reliable connection between two devices and guarantees the delivery of all data is in the correct order without any loss or corruption. However, UDP is a connectionless protocol that does not establish a connection and doesn’t guarantee reliable data transfer. 

Instead, UDP simply sends a packet of data to the recipient without any acknowledgment or error-checking mechanism. Concerning the TCP vs UDP in relationship to the VPN debate, OpenVPN works best on a UDP port, although configuration enables it to run on any port.

You can view a simple comparison of TCP and UDP below:

Does SSH Use TCP or UDP?

SSH (Secure Shell) uses TCP (Transmission Control Protocol) protocol. It is a reliable, connection-oriented protocol that provides secure and encrypted communication between two devices over a network. 

SSH uses TCP port 22 for communication and establishes a reliable connection between the client and the server.

Is HTTP TCP or UDP?

HTTP (Hypertext Transfer Protocol) is a TCP-based protocol. It uses TCP port 80 for communication and establishes a reliable connection between the client and the server to transfer hypertext.

Does DNS Work on Both TCP and UDP?

Yes, DNS (Domain Name System) can work on TCP or UDP; using TCP or UDP depends on the application’s requirements. Fundamentally, UDP is used for DNS queries because it is faster and more effective. 

However, you can use TCP for zone transfers and other functions requiring more reliability and error correction.

Merits and Demerits of TCP

The advantages of using TCP include:

1. The ability for TCP to operate independently of systems enables greater interoperability across systems and devices.
2. TCP enhances error-free data transmission and ensures that the data it sends reaches its destination intact.
3. Depending on the capacities of the receiver, the TCP optimizer enables alteration of the speed at which it transmits data.
4. TCP will confirm that data has safely arrived at its destination and will initiate a re-transfer if the first transmission fails.

As we have seen with most technologies, there is usually a flip side to every advantage; the disadvantages of TCP include:

1. You need quite a lot of bandwidth for TCP, making it slower than UDP. 
2. Losing any data during transmission, such as an image or video, renders loading other information impossible with TCP. 
3. TCP works poorly with local area networks (LAN) or personal area networks.

Advantages of UDP

The merits of using UDP include:

1. UDP considerably reduces end-to-end delay by sending smaller packets with less overhead.
2. UDP will deliver data even if some packets are missing, unlike TCP, where packet loss disrupts data transmission.
3. UDP has broadcast and multicast functionality that enables simultaneous sending of a single transmission to multiple receivers.
4. UDP transmission doesn’t require a lot of bandwidth, making it much faster and more efficient than other options, like TCP.

Setbacks to the UDP data transmission technology include:

1. The inability to check if a data packet reached its destination successfully.
2. A UDP user cannot verify if any packet got lost before arriving at the required destination during data transmission. 
3. Where data transmission is router-enabled, the priority will be on a TCP rather than a UDP packet. 
4. There is no orderliness in the arrival of packets because UDP doesn’t send data sequentially. 

Conclusion

The choice of which to use between TCP and UDP depends to a large extent on what you want to do; both UDP and TCP divide your data into data packets (smaller units), including the sender’s and recipient’s internet protocol addresses, the data you are transmitting, configurations, and the trailer. For fast and constant data transmission, you may go for UDP, but for reliability and ensuring you don’t lose any data as you transmit, you may need to go for TCP. 

Static uses, such as emailing, web browsing, and file transfer, should go with OpenVPN via TCP, while UDP is a good option for gaming, streaming, or VoIP services.