网络与协议2022 - Practice Questions - Block 1
（老师布置的practice和小卖铺资料里的历年题很像）
Question 1
Construct a Hybrid topology for a network where six computers are connected in a ring topology and five computers are connected in a tree topology.
为一个网络构建一个混合拓扑，其中六台计算机以环形拓扑连接，五台计算机以树拓扑连接。
Question 2
Write down two responsibilities of the Session layer in OSI model.
写下在OSI模型中的会话层的两个职责。
- Establishes, manages and terminates connections between applications
- Responsible for dialog control and synchronization.
-建立、管理和终止应用程序之间的连接
-负责对话控制和同步。
Question 3
List down a working model of TCP/IP Protocol Architecture maintaining proper sequence.
列出保持正确顺序的TCP/IP协议体系结构的工作模型。
Question 4
Write down the names of two parts of a PDU.
写下PDU的两个部分的名称。
At each layer, a PDU has two parts: the header and the body.
在每一层，PDU有两个部分：标题和正文
Question 5
We discussed a few applications of IoT systems using sensors and actuators in our recorded lecturers. Write down 2 more applications. What do sensors and actuators do in those applications?
我们在录制的讲师中讨论了使用传感器和执行器的物联网系统的一些应用。再写2份申请。传感器和执行器在这些应用中做什么？
（这个要自己写）
1. To prevent natural disasters, data collected by water level monitoring sensors can be used in flood warning systems for analysis and prediction, and to protect the environment, actuators that monitor high water levels will control the opening of valves.
2. Sensors that detect compounds (solids, liquids and gases) can be used for air quality monitoring, which helps cities combat the harmful effects of air and water pollution, and actuators can transmit data to appear on the operator interface of staff.
1. 为了防止自然灾害，水位监测传感器收集的数据可用于洪水预警系统进行分析和预测，保护环境，执行器监测到过高的水位将控制阀门的打开。
2. 检测化合物（固体、液体和气体）的传感器可用于空气质量监测，这有助于城市抗击空气和水污染的有害影响，执行器可以把数据传输显现在工作人员的操纵界面上。
Question 6
Why IPv6 is needed to provide unique addresses to the IoT devices in modern world?
为什么现代世界需要IPv6来为物联网设备提供唯一的地址？
IPv4 addresses are 32 bit long. Hence the address space of IPv4 address is 2^32 i.e. approx. 4 billion. There are already at least 5 billion devices connected to the internet currently. On the other hand, IPv6 addresses are 128 bit long. Therefore, IPv6 can provide unique addresses to an enormous number of IoT devices.
IPv4地址为32位长。因此，IPv4地址的地址空间为2^32，大约40亿。目前已经有至少50亿台设备连接到互联网。另一方面，IPv6地址是128位长。因此，IPv6可以为大量物联网设备提供唯一的地址。
[You can explain this in your own words. Just make sure that you keep the main keywords in the answer]
Question 7
What are the key features of the Bluetooth protocol?
蓝牙协议的主要特征是什么？
robustness, low power, and low cost.
稳健性、低功耗和低成本。
Question 8
What are the main challenges of IoT technology?
物联网技术的主要挑战是什么？
Data Explosion, Security, and Power Consumption.
数据爆炸、安全和功耗。