Who is responsible for the Presentation and Session layers in OSI?

Question

I am learning about the 7 layers of OSI. But I am currently stuck trying to understand these bottom two layers. Specifically - who performs the actions in these layers? They are called software layers but does the browser itself do all of these and how? Or the browser passes it on to a different program? How does it work?

So for example, I type in my browser google.com then the browser will establish a connection and send GET / HTTP/1.1 to the server. But how exactly each of these layers come into play?

Here is my understanding so far.

7. Layer - Application layer (Browser, HTTP)
6. Layer - Presentation layer (??)
5. Layer - Session layer (??)
4. Layer - Transport layer (Operating System)
3. Layer - Network layer (Routers)
2. Layer - Data link layer (Switches and bridges)
1. Layer - Physical layer (Modem and cables)

Answer 1

在实践中，主要使用TCP/IP 模型，并且所有三个顶层（即应用程序、表示层和会话）均由应用程序管理。

对于网络浏览器，浏览器将：

• session token会话层：为每个会话维护一个。
• http header表示层：根据服务器每个响应中的编码解析所有数据（例如Content-Type：image/png或Content-Type：text/html;charset=utf-8）
• 应用层：呈现页面并与用户交互，因为它是实现的。