Few people consider that many of our usual actions are carried out through two protocols: TCP and UDP. To properly understand their importance, it is necessary to study in detail not only their distinctive features but also their differences.
What is TCP?
TCP (Transmission Control Protocol) is a protocol that ensures reliable transmission of data packets: it establishes a connection between two hosts, after which they can exchange the necessary data.
However, this protocol is not as simple as it might seem at first glance. The TCP mechanism establishes a connection before transmitting the data stream and makes a repeat request in case of data loss. When receiving two copies of the same package, the protocol independently eliminates duplication, ensuring reliable and high-quality file transfers.
When the transmission is complete, the session closes: the recipient is notified that there will be no more data, and the sender is informed that the recipient has been notified. In case of data loss during transmission, the system automatically requests confirmation more frequently. In this way, the sliding window mechanism is implemented, allowing them to work even with unreliable networks.
TCP implementations are usually built into the OS kernel, but some also work in user space.
The most common practice is to use TCP when implementing authorization mechanisms and transmitting encrypted data.
What is UDP?
UDP (User Datagram Protocol) is a protocol that allows the transmission of data (datagrams) without establishing a connection between hosts. Thus, the technology employs a simple data transfer model to ensure integrity.
The main disadvantage of UDP is the inconsistency in receiving: datagrams may be duplicated or not arrive at all. UDP is used in systems where error checking and correction are either unnecessary or must be performed by the application.
As a rule, solutions using this protocol are not sensitive to data loss or disruption of order, or they focus on real-time content transmission (including live streaming platform provider).
TCP vs UDP. Basic theory
To understand the differences between TCP and UDP more thoroughly, it is necessary to grasp the basic theory.
What do we know about IP networks? The data stream that you send is divided into packets, then delivered to the client. Thus, IP unites individual network segments into a single network, transmitting data packets between them. In this case, the transmission occurs through an arbitrary number of intermediate nodes, or routers.
Returning to the TCP and UDP protocols, the diagram allows you to see their stack with IP.
It is important to note that both protocols have ports, but UDP only has a checksum for the length of the packet. In the case of TCP, a large amount of additional information is required, including confirmation, sequence, and packet numbers.
What is the Difference Between TCP and UDP?
Although both UDP and TCP are data-oriented, several fundamental differences between them directly affect the scope of the protocols. In addition to the features already outlined, several features radically distinguish one from the other.
Let’s identify the main points:
- Only the TCP protocol supports the ability to reassemble and segment packets.
- Accessibility verification is a mandatory procedure for the TCP protocol, while UDP generally does not support it.
- The TCP protocol cannot preserve the boundaries of transmitted messages, but it guarantees their integrity.
It should be understood that the differences between the protocols do not reveal which is best: the purposes of TCP and UDP are initially different, meaning the necessary characteristics for performing various tasks will differ.
That is why it is essential to note the following:
- UDP does not require connection setup, whereas TCP requires a mandatory three-step process flow to start a session.
- Unlike the UDP protocol, TCP provides comprehensive control and management of information flow.
- If overloads occur during data transmission, TCP will send an appropriate notification, whereas the UDP protocol does not offer protection.
- Unlike the UDP protocol, TCP cannot preserve the boundaries of transmitted messages, but it guarantees their integrity.
- TCP is never synchronized again, whereas the UDP protocol establishes a connection by resending the request to the end user.
Which is Better for Video Conferencing?
When creating a video conferencing software solution, developers often use TCP, which provides serial transmission and prevents packet loss. This protocol is the most suitable for working with video and audio, as well as for transferring images, documents, and files.
As mentioned above, TCP packets have a built-in feedback system to ensure that all data is received and sent exactly as intended.
The use of UDP significantly reduces the load on the server, because audio and video streams are transmitted within the Multicast domain, which can be used in the local network or VPN (e.g. TrueConf UTM Multicast mode). Simply put, it allows users to exchange data directly with each other during a group conference, bypassing the server.
By default, UDP Multicast data transmission is available only within your corporate closed network, eliminating the risk of losing sensitive data. If you’re interested in UDP Multicast, you can read more about it in our article.
