A Comprehensive Guide to Transport Protocol in Game Server Configuration - ECE-180D-WS-2024/Wiki-Knowledge-Base GitHub Wiki

A Comprehensive Guide to Transport Protocol in Game Server Configuration

Word Count: 1825

Introduction

Communication protocols are perceived as being essential elements in the field of online game development. It is important to note that they are not only essential when it comes to the client side, but they are also heavily emphasized in the case of server development. A suitable communication protocol has to be chosen in order for the game operation to function in both an efficient and stable manner. These transmission protocols are seen as a significant part of networked gaming as they tend to define the type of data that is transferred between servers and clients. When referring to internet protocol, two widely used options are frequently mentioned: TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) [1]. Furthermore, three factors need to be considered in the process of choosing the adequate communication protocol: ease of use, latency, and, nevertheless, the cost-effectiveness of the approached method. Considering all these elements, the content below will focus on providing a comparison of the two mentioned methods while highlighting their advantages and disadvantages, with the ultimate aim of helping developers acquire the knowledge of choosing the appropriate communication protocol for their future projects. Thus, communication protocols define the rules and conventions for data exchange between devices on a network. They ensure that data is transmitted accurately and efficiently, regardless of the underlying hardware or software differences between communicating devices. These protocols manage various aspects of data transmission, such as error detection and correction, data sequencing, and flow control.

Basic Concepts of TCP and UDP

In the early days of the internet, reliable and efficient data transmission was a significant challenge. The development of TCP/IP (Internet Protocol) suite in the 1970s by Vint Cerf and Bob Kahn laid the groundwork for modern networking. TCP and UDP were designed to address different aspects of data transmission, each optimizing for specific requirements. Both TCP and UDP are seen as basic technology building blocks of the internet, which allow data transfer between various devices. TCP is defined as being both reliable and connection-oriented. In other words, it ensures an ordered and secured transmission channel for the data between the sender and the receiver. It guarantees that data packages will be accurately transmitted and in the correct order, making it very useful for applications that require data accuracy and organizational principles, as is the case of emails or web browsing. In addition, UDP is perceived as being a form of connectionless protocol that focuses mostly on efficiency and speed rather than reliability. The fact that the data packets are provided without a dedicated connection can lead to a faster transmission rate but with the risk of duplications or loss of elements included in the packet. As per these factors, UDP remains more efficient when it comes to time-sensitive applications in which occasional loss of data packets won't have a meaningful impact. Some examples of this are represented by live broadcasting, voice/video communication, or online gambling. As it was proven, both TCP and UDP serve a very important role in digital communication, yet the choice must be made based on a balance between speed and reliability

TCP (Transmission Control Protocol)

As previously mentioned, TCP remains critical when it comes to network communication as it provides not only a reliable but also a connection-oriented service. Considering the mentioned advantages and disadvantages, it has the ability to provide both error-free and also sequential delivery of data. Due to that, this method will be effective in case of applications that function based on high accuracy. This is achieved through an established connection prior to data transmission, which does not only confirm the data receipt but also its correct order. Some of the mechanisms incorporated by the Transmission Control Protocol include flowing together with congestion and error correction in order to enhance its reliability. For example, flow control will regulate the rate of data transfer, ultimately preventing the sender from overwhelming the receiver's buffer. In addition, congestion control is known to be effective in avoiding network congestion through the adequate adjustment of the transmission of data as per the capacity of the network. Furthermore, the error correction focuses on identifying the sent packet and retransmission of any corrupted or lost elements [2].

UDP (User Datagram Protocol)

In addition, UDP is known to approach the concept of network communication in a different manner compared to TCP. An essential pillar for this technology is represented by its connectionless service. Despite being less reliable than TCP, the data packet sending is a lot faster. This would mean that UDP will not guarantee the integrity of the order of the data packets, but it will ensure it will be delivered in a fast manner. This makes it perfect for that application in which speed outweighs precisions. Examples of this include online gaming, VoIP, and video streaming. It is important to note that the fast transmission of data comes with a higher risk of either disarray or packet loss during this process. Despite being classified as a simpler protocol, UDP will allow for both broadcast transmission and multicast. This means that a single sender will be able to communicate with multiple receivers during a single operation. Furthermore, it is known to use less bandwidth compared to TCP. Even so, due to the disadvantages previously mentioned, it also required additional coding to ensure that the important elements of the packets are not lost in the transmission and that the application functionality runs smoothly [2].

Differences between TCP and UDP

Transmission Control Protocol is a connection-based protocol, it guarantees that before the data is sent to a receiver some type of dedicated arrangement is made between the sender and receiver. This configuration also facilitates error checking and correction, ensuring that data packets are received in the precise order as they were initially sent; hence, TCP reliability is very high. For example, in web browsing, when a user asks for a webpage and receives one, TCP guarantees that all the components of the requested page are delivered correctly and displayed as intended. In the same manner, in the transmission of emails as well as transferring files, the reliability that comes with TCP ensures that messages and files are delivered whole without any part missing or tampered with [6]. In contrast, UDP is a protocol without connection; in other words, it does not create the bond between sender and receiver prior to transmitting data. This has the effect of speeding up the transmission of data because it bypasses the overhead cost due to connection establishment, error checks, and corrections. On the other hand, this implies that UDP does not ensure data packet delivery, order or integrity of data packets. For instance, in live video distribution or gaming on the Internet, UDP is preferred because it has low latencies and low buffering times, consequently creating a much better user experience. Even if a few packets are lost, or some get disordered, the impact on user experience is less as compared to a delay caused by TCP’s retransmission of lost packets and its effort to reorder them [6].

Figure 1: Comparative table depicting the primary differences between TCP and UDP [3]

The necessity of TCP and UDP stems from their ability to cater to different requirements in network communication. While TCP ensures data integrity and reliability, UDP provides the speed and efficiency needed for real-time applications. Together, they form the backbone of modern internet communication, allowing for a diverse range of applications to function effectively and efficiently. Understanding the roles and capabilities of these protocols is crucial for optimizing network performance and ensuring the appropriate use of resources in various digital communication scenarios.

Comparison of the Processes of TCP and UDP

The process of TCP communication starts with a three-way handshake, where the sender and receiver exchange synchronization (SYN) and acknowledgment (ACK) packets to establish a connection. Once the connection is established, data is transmitted in ordered packets, with each packet being acknowledged by the receiver to confirm receipt. TCP manages the rate of data transmission based on the receiver’s ability to process the incoming data, preventing buffer overflow. Additionally, TCP adjusts the transmission rate according to network traffic conditions to avoid congestion and packet loss. After the data transmission is complete, the connection is terminated using a four-way handshake, ensuring that both parties agree to end the communication session. Unlike TCP, UDP does not establish a connection before sending data, resulting in faster transmission. The process of UDP communication involves transmitting data packets directly without establishing a connection. Each packet is independent, and there is no handshake process. UDP does not wait for acknowledgments from the receiver, which reduces latency but increases the risk of packet loss. UDP does not maintain any state information between packets, allowing for faster transmission but with the possibility of packet disorder or loss.

Use Cases in Gaming

In the early days of gaming, local multiplayer games required minimal network infrastructure, as all interactions occurred within the same physical space. However, with the advent of the internet and the increasing popularity of online multiplayer games, the need for efficient and reliable network communication protocols became paramount. Early online games often struggled with latency and data loss, impacting the player experience and driving the need for more sophisticated solutions. Modern games often use both TCP and UDP to leverage the strengths of each protocol. TCP handles non-time-sensitive data, while UDP manages time-critical data, optimizing network communication based on the specific needs of different game mechanics.

In the world of computer games, depending on which approach is chosen for transmitting system commands between players over a network – TCP or UDP – game performance and player experience can vary quite dramatically, not to mention the overall reliability of synchronization. Every protocol deals with different games and gaming mechanics according to the nature of these mechanics and the game network communication needs.

Figure 2: Depiction of the most widely used MMORPGs and their employed protocols [5].

TCP Usage

TCP, designed to be reliable and orderly with its error correction features, is best suited for games that allow a minor delay in communication without interfering with the quality of gaming. This makes it a perfect option for strategy games, where each action of the player is strictly differentiated by turns, e.g.chess or card games online, and the value of each transmitted move is higher than its quickness. Here, the mechanisms in TCP make sure that all game states get shared between clients correctly and that all of them are updated accordingly, thereby ensuring the integrity of the game. Moreover, TCP is commonly used in the chat part of online games this is because through it, messages are delivered, hence making player-to-player communication secure and constant [4].

UDP Usage

Conversely, UDP is ideal under circumstances where urgency and high rates of processing are more important than sheer perfection. This is especially true in time-sensitive, real-time networked games such as first-person shooters (FPS), strategy, and role-playing games (RPG), where players' positions, actions, and game states change frequently and must be broadcast to all participants nearly instantly. In such games, minor packet loss and out-of-order delivery are acceptable sacrifices for low latency and better gameplay. Using UDP provides a fast transfer of small, often changing data, which is important for maintaining the synchronization of all players' views on the world. Although some data can be lost or received out of order, the game developers normally use special error correction and state reconciliation mechanisms implemented on top of UDP to handle these problems in a minimal way. This may involve prediction algorithms to anticipate player movements or fallback strategies to compensate for missed updates, ensuring the gameplay is smooth and responsive even in the presence of occasional packet drops [4].

Optimizing Gaming Performance with TCP and UDP

Real-time strategy games (e.g., StarCraft) and MOBAs (e.g., League of Legends) balance speed and reliability, using UDP for fast commands and TCP for critical data. Sports games (e.g., FIFA) and racing games (e.g., Forza Horizon) rely on UDP for real-time interactions and fluid gameplay.

Conclusion

The discussion about TCP and UDP in terms of online gaming and server configuration highlights the subtler concerns that developers must pay attention to so as to get better network communication. However, with the changing digital landscape, emerging technologies and protocols might present new possibilities to improve game networking. However, with the continuous innovations in network infrastructure particularly 5G wireless technology will further minimize latency and offer a more dependable mobile gaming experience. Furthermore, the emergence of application-specific protocols built on top of UDP such as QUIC is another indication that the industry continuously seeks to unite UDP-like fastness with reliability mechanisms often attributed to TCP. The above trends address the fluid adoption of network protocol implementation in gaming, and this implies that an adaptive or hybrid approach may soon be popular, depending on the specific needs posed by a game’s architecture design as well as gameplay experience. In addition, the implementation of artificial intelligence (AI) and machine learning (ML) in network management might change the game servers’ adjustment to the alterations of real-time network conditions making it possible to provide ideal player experience on dynamic internet quality. Through forecasting network congestions and dynamically tuning protocol parameters or even triggering TCP to UDP mode switching whenever necessary, AI capable servers could offer consistent quality of experience for a wide range of games’ genres under varying network scenarios. This anticipatory view will only promote further research and innovation in the area of network protocol design and implementation, thus highlighting once again the importance of adaptive intelligent networking solutions for the future of online gaming.

References

  1. Beginner's Guide to Game Networking, 08 Sep 2019 by pierre https://pvigier.github.io/2019/09/08/beginner-guide-game-networking.html
  2. TCP vs UDP, Dec 24, 2020 by Megh Agarwal https://meghagarwal.medium.com/tcp-vs-udp-c3dedd91f66d
  3. TCP vs UDP: What’s the Difference and Which Protocol Is Better? https://www.avast.com/c-tcp-vs-udp-difference#
  4. UDP vs TCP: Why to Run Gaming Servers Separate from Chat, Nov 29, 2023 by PubNub https://medium.com/@PubNub/udp-vs-tcp-why-to-run-gaming-servers-separate-from-chat-f8e64dbf3952
  5. An Empirical Evaluation of TCP Performance in Online Games by Kuan-Ta Chen, Chun-Ying Huang, Polly Huang, and Chin-Laung Lei https://homepage.iis.sinica.edu.tw/~swc/pub/tcp_in_games.html
  6. Performance comparison between TCP and udp protocols in different simulation scenarios, by Al-Dhief et al., https://www.researchgate.net/publication/329944111_Performance_comparison_between_TCP_and_udp_protocols_in_different_simulation_scenarios