2. Circuit-Switching Circuit-switching network establishes circuit between nodes and terminals. It doesn'd need high technique to establish but It makes some ploblem. For example, when sender and receiver's sending speed is different, it makes delay of sending information.
3.
4. Analog signal and Digital signal Analog signal change date into voltage, current and charge. But Analog signal make noise because turbulence. So error margin gose out when returning it. Digital signal change date into numerical value. There is no error margin and former date can be restored because the numerical value has scattered.
5. Fierwall A firewall is a part of a computer system that blocks unauthorized access when permitting authorized communications. Thanks for it, our computers are protected from some serious trouble.
![How Circuit-Switched Digital Networks Work ,[object Object],[object Object],[object Object],[object Object],Group A s1170135 Fuyuki Ito s1170140 Kazuho Okuyama s1170141 Keiya Kato s1170142 Eisuke Kamiya](https://image.slidesharecdn.com/w11-091221211149-phpapp01/85/W11-1-320.jpg)
