> For the complete documentation index, see [llms.txt](https://http3-explained.haxx.se/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://http3-explained.haxx.se/zh/the-protocol/feature-trans-app.md).

# 传输层与应用层协议

IETF版QUIC是一个传输层协议，在该协议之上可以运行其他应用层协议。初始的应用层协议是HTTP/3（h3）。

传输层协议负责连接和数据流处理。

在Google的传统QUIC中，传输层与HTTP融在一起，为包揽一切的全功能设计，它是一个更有指向性的“基于UDP传输HTTP/2帧”（send-http/2-frames-over-udp）的协议。


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://http3-explained.haxx.se/zh/the-protocol/feature-trans-app.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.