{
  "id": 105901,
  "title": "Building Reliable UDP",
  "url": "https://urgent.news/2026/08/03/building-reliable-udp",
  "topic": "culture",
  "section": "Culture",
  "published": "2026-08-03T23:20:28.000Z",
  "source": {
    "name": "Dev.to",
    "slug": "dev-to",
    "url": "https://dev.to/derekmwale/building-reliable-udp-51ei"
  },
  "original_language": "en",
  "account": "Building Reliable UDP: A Guide to Enhancing UDP's Limitations\nMost developers default to using TCP when considering networking. This is because TCP guarantees data integrity, order, and delivery. However, there are instances where UDP is preferred, such as online multiplayer games, live video streaming, voice-over-IP, DNS, IoT devices, and real-time telemetry. The reason for this choice lies in UDP's ability to provide developers with control over the protocol, optimizing it for their specific application needs.\n\nReliable UDP is not a separate protocol but an engineering pattern that rebuilds some TCP capabilities, only the ones necessary for the application. Let's create reliable UDP from scratch by understanding UDP, its advantages, and its drawbacks.\n\nUnderstanding UDP\nImagine tossing a letter into the wind, hoping it reaches its destination. This represents UDP. With no handshakes, confirmations, or guarantees, UDP simply sends packets into the network, hoping for the best. Despite these limitations, UDP offers significant benefits, particularly in situations where guarantees come at a cost. TCP introduces connection setup, congestion control, flow control, retransmissions, ordered delivery, and head-of-line blocking. While these features are essential in certain scenarios, they can be unnecessary in others.\n\nWhy Would Anyone Use UDP?\nThe decision to use UDP instead of TCP is often puzzling. After all, UDP doesn't guarantee delivery, order, or prevent duplicates. It doesn't even ensure that a receiver exists. This seems terrifying, but engineers choose UDP because it provides them with something invaluable: control. Instead of accepting TCP's built-in reliability mechanisms, developers can design their own, tailored to their specific application needs.\n\nDesigning Reliable UDP\nTo create reliable UDP, we'll design and implement several mechanisms that transform UDP into a dependable transport layer. These mechanisms include sequence numbers, acknowledgements, retransmissions, timeouts, sliding windows, duplicate detection, and packet ordering.\n\nPacket Structure\nOur first step is to design a custom packet format. The packet will consist of the following fields:\n\n+--------------------------------+ | Sequence Number | +--------------------------------+ | Acknowledgement | +--------------------------------+ | Flags | +--------------------------------+ | Payload | +--------------------------------+\n\nEach field serves a specific purpose, such as tracking sequence numbers, acknowledgements, and duplicate detection.\n\nRust Representation\npub struct Packet {\npub sequence : u32 ,\npub acknowledgement : u32 ,\npub flags : u8 ,\npub payload : Vec < u8 > ,\n}\n\nAcknowledgements\nThe receiver confirms successful delivery of packets by sending acknowledgements. The sender removes the acknowledged packet from memory, ensuring efficient communication.\n\nRetransmissions\nTo handle lost packets, the sender starts a retransmission timer for each sent packet. If an acknowledgement is not received within the timeout period, the sender resends the packet. This mechanism significantly improves reliability.\n\nTimeouts\nChoosing appropriate timeout values is crucial for maintaining optimal performance. Too short, and unnecessary retransmissions occur. Too long, and recovery becomes slow. Typical timeout values range from 500 ms to several seconds, and adaptive protocols dynamically adjust these values based on network conditions.\n\nDuplicate Detection\nNetworks sometimes duplicate packets, leading to potential issues. To handle duplicate packets, the receiver maintains a set of processed sequence numbers. If an incoming packet's sequence number is already present in the set, it is ignored, ensuring that only unique packets are processed.\n\nPacket Ordering\nIn some cases, packets may arrive out of order. To address this issue, we maintain a buffer that stores incoming packets. Once the buffer is filled, the packets are sorted based on their sequence numbers before delivery to the application. This ensures that the application receives packets in the correct order, regardless of the order they arrived in.",
  "summary": "How to Turn an Unreliable Protocol into One You Can Trust When most developers think about networking, they immediately think of TCP . After all, TCP powers web browsing, APIs, databases, email, and countless distributed systems. It guarantees that data arrives in order, without duplication, and without corruption. But there's another protocol that quietly powers some of the fastest systems in…",
  "key_points": [
    "Reliable UDP is an engineering pattern that rebuilds TCP capabilities, only necessary ones",
    "Packet structure includes sequence number, acknowledgement, flags, and payload"
  ],
  "editors_take": "Building reliable UDP enables developers to tailor their networking to specific application needs, offering control and efficiency in situations where TCP's guarantees would introduce unnecessary overhead or latency.",
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}