# 和NATS的关系

NATS Streaming Server by default embeds a [NATS](https://github.com/nats-io/nats-server) server. That is, the Streaming server is not a server per-se, but instead, a client to a NATS Server.

It means that Streaming clients are not directly connected to the streaming server, but instead communicate with the streaming server *through* NATS Server.

This detail is important when it comes to Streaming clients connections to the Streaming server. Indeed, since there is no direct connection, the server knows if a client is connected based on heartbeats.

***It is therefore strongly recommended for clients to close their connection when the application exits, otherwise the server will consider these clients connected (sending data, etc...) until it detects missing heartbeats.***

The streaming server creates internal subscriptions on specific subjects to communicate with its clients and/or other servers.

Note that NATS clients and NATS Streaming clients cannot exchange data between each other. That is, if a streaming client publishes on `foo`, a NATS client subscribing on that same subject will not receive the messages. Streaming messages are NATS messages made of a protobuf. The streaming server is expected to send ACKs back to producers and receive ACKs from consumers. If messages were freely exchanged with the NATS clients, this would cause problems.


---

# Agent Instructions: 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:

```
GET https://docs.natsclub.cn/cn/yi-chan/stan/intro/relation-to-nats.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.