TCP reliable / UDP unreliable hoax

Education trains obedience to abstractions, not understanding of systems.


🔹 1. "TCP reliable / UDP unreliable" is a pedagogical simplification

Teachers present it as:

TCP = reliable stream

UDP = unreliable datagram

Students interpret it as:

UDP cannot be made reliable.

But the real story is:

TCP provides reliability because the kernel implements it.

UDP is merely a raw message delivery primitive.

Reliability is not inherent to TCP --- it is implemented logic:

  • sequence numbers
  • acknowledgments
  • retransmission
  • congestion control
  • flow control
  • reordering
  • fragmentation handling

These are just features someone chose to put in the kernel.

Nothing stops you from implementing all of that in user space over UDP --- and people do:

✔ QUIC (Google, now HTTP/3) -- reliable, congestion-controlled, over UDP

✔ RTP + RTCP + FEC -- reliable(ish) streaming

✔ ENet -- reliable ordered UDP for game engines

✔ RakNet -- reliable messaging for games

✔ WebRTC DataChannels -- reliable UDP streams

So the "TCP reliable / UDP unreliable" story is just a classroom slogan, not a truth.

When people only learn slogans, they stop asking "why?".


🔹 2. Tutorials often teach consumption, not construction

Most textbooks tell you:

"use TCP if you want reliability"

But never:

"here's how reliability works underneath and why it matters."

This produces engineers who can use sockets but cannot build transports.

Same pattern repeats:

  • "use SQL" → not "here's how indexing and query optimization work"
  • "use Kubernetes" → not "here's how scheduling and orchestration works"
  • "use Python" → not "here's how a VM executes bytecode"
  • "use AES" → not "here's why block ciphers are designed the way they are"
  • "use AI API" → not "here's how attention or tokenization works"

It's training for dependency, not independence.


🔹 3. Why schools teach half-stories

Partly because it's easier:

  • simplifies grading
  • reduces cognitive load
  • avoids system-level complexity
  • fits standardized curriculum

But the more subtle reason:

teaching you how to build systems creates people who don't need systems anymore.

Institutions (education, corporations, government) prefer producing operators , not inventors.

An operator is someone who:

  • calls APIs
  • configures tools
  • consumes platforms
  • depends on external infrastructure

An inventor is someone who:

  • builds alternatives
  • creates new platforms
  • threatens monopolies
  • understands internals

The world systemically rewards operators, because they plug into the machine.

Inventors complicate the power structure.


🔹 4. This ties into points about lock-in

When people believe UDP "cannot" be reliable, they stop experimenting.

When people believe frameworks "must" be used, they stop building replacements.

Same root dynamic:

  1. Abstractions become dogma
  2. Dogma becomes curriculum
  3. Curriculum produces dependency
  4. Dependency reinforces the platform

Knowledge becomes siloed and rare.


🔹 5. TCP is actually a historical limitation

Here's a twist:

The fact that TCP is in the kernel actually makes it hard to evolve:

  • changing congestion control requires kernel upgrades
  • new features require RFC standardization
  • ossification happens (middleboxes block new behavior)

Google's QUIC exists precisely because TCP became ossified.

So they moved reliability to user space over UDP

And HTTP/3 is now QUIC by default.

The system came full circle --- user-space reliability won.


🔹 6. Cognitive takeaway

Here are points to a deeper intellectual skill:

Don't treat abstractions as truths.
Treat them as design choices.

Once you see that engineering is just layered decisions, you can imagine alternatives.

Most people never reach that level because they were taught:

  • what to use
  • not how to think
相关推荐
cheems952714 小时前
【javaEE】全方位拆解 UDP 协议
网络·网络协议·udp
wenzhangli72 天前
OoderAgent SDK(0.6.6) UDP通讯与协议测试深度解析
网络·网络协议·udp
Trouvaille ~2 天前
【Linux】UDP Socket编程实战(一):Echo Server从零到一
linux·运维·服务器·网络·c++·websocket·udp
郝亚军2 天前
ubuntu启一个udp server,由一个client访问
linux·ubuntu·udp
Trouvaille ~2 天前
【Linux】UDP Socket编程实战(二):网络字典与回调设计
linux·运维·服务器·网络·c++·udp·操作系统
Trouvaille ~3 天前
【Linux】UDP Socket编程实战(三):多线程聊天室与线程安全
linux·服务器·网络·c++·安全·udp·socket
Trouvaille ~3 天前
【Linux】UDP Socket编程实战(四):地址转换函数深度解析
linux·服务器·网络·c++·udp·socket·地址转换函数
oushaojun23 天前
趣谈网络协议栈,以太网基础MAC和PHY(转)
mac·tcp·linux网络·phy
中议视控3 天前
浅谈Modbus,CRC,kNX,DMX512,KNZ,TCP/UDP等协议算法在可编程网络中央控制系统主机中的重要性
网络·tcp/ip·udp
Beaman08283 天前
第二章 传输层TCP UDP
网络协议·tcp/ip·udp