TCP vs UDP Protocols
Published: 2023-02-09 18:53:33

TCP and UDP are the most used transport protocols. They enable accessing websites resources and data transmissions, but which one should you use ?
In this guide, we will compare TCP vs UDP and how they differ from each other. Let’s dive in!

## What are Internet Protocols?

Before we discuss TCP and UDP, we need to understand what an internet protocol is. The [Internet Protocol](https://en.wikipedia.org/wiki/Internet_Protocol) is a set of rules for routing and addressing parts of data so that it can travel across networks.

Before data is sent across a network, it is divided into smaller pieces called Packets. Every device that connects to the internet is assigned with an IP address, which packets are directed to. Once packets arrive at the device, they are handled differently depending on which transport protocol is used with the IP. The most common transport protocols are TCP and UDP.

## What is TCP?

TCP is a Transmission Layer Protocol, it provides a reliable connection and protected data transmission between the connected devices. It first established a secure link before sending data.

While TCP is slow in data transmission, it has more functionalities including flow and error control. As TCP is reliable, it is used with web protocols like HTTP and FTTP to secure data over the network. 

The TCP protocol is connection-based, it means that it creates and maintains connection between sender and receiver. This process results in a more significant overhead size, which means that it consumes more bandwidth.

Now let’s discuss the pros and cons of TCP protocol.

### Pros
 

- Acknowledgment
Sometimes between data transmission, data may get lost failing to reach its destination. Due to this acknowledgment, the sender can re-transmit this data again.

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- Guaranteed Delivery
If the server didn’t receive the data or the data was corrupted during transmission. The sender keeps retrying until data is delivered.

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- Congestion Control
TCP uses a separate congestion control policy, this happens when the sender sends too many data packets in a given time.

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- Unique Identification
Each device connected has a unique IP address, making it identifiable over the network.

### Cons

- Slow Start
As TCP starts by establishing a secure connection between two devices, it’s always slow at the beginning.

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- Slow Handshake
When a connection is established, TCP performs a three-way handshake. This leads the connection establishment to slow down.

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- More Bandwidth
As TCP has many features, it adds more packets to enable these features. This leads to more bandwidth consumption.

## What is UDP?

UDP is User Datagram Protocol, it’s connectionless meaning that it doesn’t establish a connection between devices like TCP. UDP is used for situations where speed is a critical factor like video streaming or online games.

UDP doesn’t guarantee the transfer of all data. This is why it’s called “fire-and-forget” protocol. The UDP header has fixed size, this means that it’s unreliable but fast.

Now let’s discuss the pros and cons of UDP.

### Pros

- Less Bandwidth
UDP uses a small packet size, this means less bandwidth and memory consumption.

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- Fast
UDP is fast but it doesn’t guarantee the delivery of all packets.

### Cons

- Unreliable
As UDP doesn’t establish a connection between devices, connection can be unreliable.

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- Unguaranteed Delivery
Packets may not be delivered or delivered twice.

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- No Congestion Control
Since UDP transmits a large amount of data, it can cause congestion without controlling it.
 
## TCP vs UDP

After we talked about TCP and UDP, let’s compare TCP vs UDP to know which is better for your case.

TCP is a connection-oriented protocol, it relies on a passive open state. This means that both devices need to accept connection between each other.
Comparatively, UDP is a connectionless protocol. This means that data transmission involves an endpoint without waiting the other side to accept a connection 

TCP sends data in a particular sequence, This allows the system to track the order in which data is transmitted.
On the other hand, UDP doesn’t follow a sequence, data packets are sent independently with no fixed order

Since TCP needs to establish a connection, it’s slow compared to UDP which is connectionless.

TCP adds more resources to a response which makes it consume more bandwidth than UDP.

Another difference between TCP and UDP is that UDP doesn’t guarantee delivery of data.

## Conclusion

In this guide we discussed:
- What TCP and UDP are.
- The pros and cons of TCP and UDP.
- TCP vs UDP and which is better for your case.

In a nutshell, TCP is more reliable and secure than UDP but it’s slower than UDP.

TCP is better where reliability and security are important like chatting applications.

UDP is better where speed is more important like streaming and online games.