根据图上给出信息制作教学视频---Here is the extracted content from the image:
**Chapter 1.**
**① "nuts and bolts" view**
**internet**
- ① Network Edge (host, server, PC.)
- ② Core (packet switch, Router,) -> Store and Forwarding
- ③ Communication Link
- Wired: fiber,
- Wireless: radio (radio)
**② Delay**
1. transmission delay > X
2. Propagation delay > X
3. Processing -> check error, output interface
4. queuing -> wait to transmit.