计算机系统中协议的定义及HTTP/TCP/IP协议规则的正确性确认

Hey there! Awesome question—you’ve already got a solid grasp of how network protocols function. Let’s walk through your examples to confirm everything and clarify a few details:

Your overall understanding hits the mark—network protocols are exactly these sets of standardized rules, formats, and mechanisms that let computers communicate reliably. Let’s verify each protocol’s rules you listed:

HTTP Protocol Rules #

• 确定请求所采用的方法（GET、POST等）: 100% correct. HTTP defines a set of request methods that dictate the intent of the request (e.g., fetching data with GET, submitting data with POST). This is a core part of HTTP’s request structure.
• 确定请求发送至哪个主机: Correct. This maps to the Host header in HTTP/1.1, which is mandatory—it lets servers distinguish between multiple domains hosted on the same IP address.
• 确定请求文件的格式: Your direction is right, but let’s refine this: HTTP specifies the format and encoding of request/response data (via headers like Content-Type, e.g., application/json, text/html). It’s not just "file format" but the entire structure of data exchanged.
• 确定向服务器发送哪些Cookie数据: Correct. Cookies are an HTTP-specific mechanism for maintaining state, passed via the Cookie request header—this is absolutely part of HTTP’s rules.
• 确定请求发送至哪个端口: Technically, ports belong to the TCP layer, but HTTP has default port conventions (80 for unencrypted HTTP, 443 for HTTPS). So while the port is established in the TCP connection, HTTP’s default ports are a standard part of how the protocol is used day-to-day.

TCP Protocol Rules #

• 记录数据发送的端口: Correct. TCP headers include source and destination port fields, which identify which application on each device is communicating.
• 将数据分割为数据包并为每个数据包分配编号，以便接收数据的计算机能正确重组数据包: Perfect. This is TCP’s segmentation and sequence number mechanism—critical for ensuring data arrives in order and can be reassembled correctly.
• 当数据包在传输途中丢失时，具备重新请求获取丢失数据包的规则: Correct. This is TCP’s retransmission mechanism, powered by acknowledgments (ACKs) and timeout logic. It’s what makes TCP a reliable transport protocol.

IP Protocol Rules #

• 提供源IP地址和目的IP地址，并决定数据包应通过哪些路由器传输（路由器工作在该层级）等: Exactly right. IP headers contain source and destination IP addresses, and routing (determining the path through routers) is a core function of the IP protocol. Routers operate at the network layer (IP layer) to forward packets along the correct path.

A Quick Note on "General Rules" #

Some of these rules are protocol-specific: for example, HTTP’s request methods and cookies are unique to HTTP. Others are core mechanisms of their network layer: TCP’s sequencing/retransmission and IP’s addressing/routing are defining features of those protocols—different protocols in the same layer (like UDP instead of TCP) won’t have all these rules (UDP has no retransmission or sequencing, for example).

All in all, your understanding is spot-on—these are exactly the kinds of rules that make up network protocols. Protocols exist to eliminate ambiguity so computers can "speak the same language" during communication.

内容的提问来源于stack exchange，提问作者Samvel Ghumashyan