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一. 大纲要求
Candidates should be able to:
考生应能：
Show understanding of the purpose and benefits of networking devices
展示对网络设备目的和好处的理解
Show understanding of the characteristics of a LAN (local area network) and a WAN (wide area network)
展示对局域网（LAN）和广域网（WAN）特性的理解
Explain the client-server and peer-to-peer models of networked computers
解释网络计算机的客户端-服务器和点对点模型
Show understanding of thin-client and thick-client and the differences between them
展示对薄客户端和厚客户端及其差异的理解
Show understanding of the bus, star, mesh and hybrid topologies
展示对总线、星型、网状和混合拓扑的理解
Show understanding of cloud computing
展示对云计算的理解
Show understanding of the differences between and implications of the use of wireless and wired networks
展示对无线网络和有线网络使用的差异及其影响的理解
Describe the hardware that is used to support a LAN
描述用于支持局域网的硬件
Describe the role and function of a router in a network
描述网络中路由器的角色和功能
Show understanding of Ethernet and how collisions are detected and avoided
展示对以太网以及如何检测和避免碰撞的理解
Show understanding of bit streaming
展示对位流的理解
Show understanding of the differences between the World Wide Web (WWW) and the internet
展示对万维网（WWW）和互联网之间差异的理解
Describe the hardware that is used to support the internet
描述用于支持互联网的硬件
Explain the use of IP addresses in the transmission of data over the internet
解释在互联网上数据传输中IP地址的使用
Explain how a Uniform Resource Locator (URL) is used to locate a resource on the World Wide Web (WWW) and the role of the Domain Name Service (DNS)
解释如何使用统一资源定位符（URL）在万维网（WWW）上定位资源及域名服务（DNS）的角色
二.大纲解读
1. Purpose and Benefits of Networking Devices
Networking devices play a crucial role in connecting and managing multiple devices within a network. They enable efficient and reliable data exchange. Common devices include switches, routers, bridges, and access points. Switches forward data packets within a LAN, while routers facilitate communication between different networks. The benefits of networking devices include increased transmission speed, data security, and scalability to adapt to network growth.
网络设备在网络中起到了关键作用，用于连接和管理多个设备，保证数据的高效和可靠传输。常见的网络设备包括交换机、路由器、网桥和接入点。交换机在局域网内转发数据包，路由器帮助不同网络之间的通信。网络设备的优点包括提高传输速度、保证数据安全性和支持网络扩展。
2. Characteristics of LAN (Local Area Network) and WAN (Wide Area Network)
A LAN typically covers a limited geographical area, like a building or office, connecting a smaller number of devices. It provides fast transmission speeds, low latency, and relatively straightforward configuration. A WAN, however, connects over large areas or even internationally, relying on telecom providers, with higher latency and slower transmission speeds but broader reach.
局域网（LAN）通常覆盖较小的地理范围，比如建筑或办公室，连接较少的设备。它具有传输速度快、延迟低、配置相对简单的特点。广域网（WAN）则用于较大区域甚至国际连接，通常依赖电信服务商，延迟较高且传输速度较慢，但覆盖范围更广。
3. Client-Server vs. Peer-to-Peer Models
In the client-server model, a server acts as a centralized provider of resources and services, while clients are endpoint devices that request resources. This model suits applications needing centralized management, such as web or database servers. Peer-to-peer (P2P) allows devices to act as both clients and servers, without centralized control, and is ideal for file sharing applications.
在客户端-服务器模型中，服务器作为资源和服务的集中提供者，客户端则是请求资源的终端设备。这种模型适合需要集中管理的应用，如网页或数据库服务器。点对点（P2P）模型允许设备既作为客户端也作为服务器，无需集中管理，适用于文件共享等应用。
4. Thin-Client vs. Thick-Client
Thin clients rely on servers to handle most processing tasks, making them suitable for centrally managed and secure environments. Thick clients have more powerful processing abilities, allowing them to operate independently with reduced reliance on servers. Their differences lie mainly in hardware configuration and resource distribution.
瘦客户端依赖服务器完成大部分处理任务，适用于集中管理和安全性要求较高的环境。厚客户端则拥有更强的处理能力，能独立执行更多任务，减少对服务器的依赖。两者的差异主要在于硬件配置和资源分布方式。
5. Bus, Star, Mesh, and Hybrid Topologies
- Bus Topology: All devices connect via a single backbone line; it’s simple but challenging for troubleshooting.
- Star Topology: Devices connect through a central node (like a switch), offering reliability, though failure at the central point disrupts the network.
- Mesh Topology: Each device connects with multiple devices, providing redundancy and fault tolerance but at higher cost.
- Hybrid Topology: Combines multiple topologies to meet diverse network needs.
- 总线拓扑：所有设备通过单一主干线连接，结构简单，但故障排查较难。
- 星型拓扑：所有设备通过中央节点（如交换机）连接，可靠性高，但中央节点故障会导致网络中断。
- 网状拓扑：每个设备与多个设备相连，提供冗余和容错，但成本高。
- 混合拓扑：结合多种拓扑结构，满足不同的网络需求。
6. Cloud Computing
Cloud computing offers computing resources over the internet, allowing users on-demand access to storage, computational power, and software services. It’s advantageous for its flexibility, high scalability, and reduced hardware maintenance costs.
云计算通过互联网提供计算资源，用户可以按需访问存储、计算能力和软件服务。它的优势在于灵活性高、扩展性强，并减少了硬件维护成本。
7. Differences Between Wireless and Wired Networks
Wireless networks enable connections without physical cabling, though they are susceptible to interference and typically have slower data transfer rates. Wired networks offer more stable and secure connections but require cabling. Wireless networks are ideal for high mobility, whereas wired networks suit environments requiring high stability and security.
无线网络无需物理连接即可接入网络，但易受干扰，数据传输速度较慢；有线网络提供更稳定和安全的连接，但需要布线。无线网络适合高移动性需求场景，而有线网络适用于需要高稳定性和安全性的环境。
8. Hardware Used to Support LANs
LAN-supporting hardware includes switches, routers, bridges, wireless access points, and network interface cards (NICs). Switches connect multiple devices, routers manage data transfer between networks, bridges connect LAN segments, wireless access points enable wireless connections to a wired network, and NICs establish physical device connections to the network.
支持局域网的硬件包括交换机、路由器、网桥、无线接入点和网卡。交换机连接多个设备，路由器管理网络间的数据传输，网桥连接LAN段，无线接入点使无线设备接入有线网络，网卡负责设备的物理网络连接。
硬件比较
Let’s compare these network devices based on their functions and use cases:
- Switches:
- Function: Switches operate at the Data Link layer (Layer 2) of the OSI model and are used to connect devices within the same network. They manage the flow of data across a network by turning a broadcast domain into multiple collision domains, which helps prevent packet collisions on a network that uses a shared medium.
- Use Case: Commonly used in local area networks (LANs) to connect multiple devices, such as computers and printers, allowing for efficient data transfer and communication within the same network.
- Routers:
- Function: Routers operate at the Network layer (Layer 3) and are used to connect multiple networks, directing data packets between them. They use IP addresses to determine the best route for data packets to travel across multiple networks.
- Use Case: Essential for internet connectivity and large network setups where data needs to be transmitted across different networks, such as between a home network and the internet.
- Bridges:
- Function: Bridges also operate at the Data Link layer (Layer 2) and are used to divide a network into separate collision domains to reduce traffic and increase performance. Unlike switches, bridges typically have fewer ports and are used in simpler or older network setups.
- Use Case: Useful in extending the range or dividing segments of a network to reduce traffic load but have largely been replaced by switches in modern networks.
- Wireless Access Points (WAPs):
- Function: Wireless Access Points operate across data link and physical layers and provide a wireless local area network (WLAN) by projecting a Wi-Fi signal to which wireless-capable devices can connect.
- Use Case: Commonly used in homes and businesses to allow wireless devices to connect to the network and access resources like the internet or printers.
- Network Interface Cards (NICs):
- Function: NICs operate at both the Physical and Data Link layers and are hardware devices that allow a computer or other device to connect to a network. They can be wired (Ethernet NIC) or wireless (Wi-Fi NIC).
- Use Case: Every device that connects to a network has a NIC that provides the hardware interface between the computer and the network.
Each of these devices plays a crucial role in building and managing networks, with specific functions tailored to different networking needs and scenarios.
让我们基于它们的功能和使用场景来比较这些网络设备：
- 交换机（Switches）：
- 功能：交换机工作在OSI模型的数据链路层（第2层），用于连接同一网络内的设备。它们通过将广播域划分为多个碰撞域来管理网络中的数据流，有助于防止使用共享介质的网络上的数据包碰撞。
- 使用场景：常用于局域网（LAN）中连接多个设备，如计算机和打印机，以实现同一网络内的高效数据传输和通信。
- 路由器（Routers）：
- 功能：路由器工作在网络层（第3层），用于连接多个网络，指导数据包在它们之间的传输。它们使用IP地址来确定数据包穿越多个网络的最佳路径。
- 使用场景：对于需要在不同网络之间传输数据的互联网连接和大型网络设置（如家庭网络与互联网之间）至关重要。
- 网桥（Bridges）：
- 功能：网桥也工作在数据链路层（第2层），用于将网络划分为不同的碰撞域以减少流量并提高性能。与交换机不同，网桥通常端口较少，用于更简单或较旧的网络设置。
- 使用场景：有助于扩展网络范围或划分网络段以减少流量负载，但在现代网络中大多已被交换机取代。
- 无线接入点（Wireless Access Points, WAPs）：
- 功能：无线接入点在数据链路层和物理层上操作，它们提供无线局域网（WLAN），通过发射Wi-Fi信号使得无线设备能够连接。
- 使用场景：在家庭和企业中常用，以便无线设备能够连接到网络并访问如互联网或打印机等资源。
- 网络接口卡（NICs）：
- 功能：网络接口卡在物理层和数据链路层上操作，是允许计算机或其他设备连接到网络的硬件设备。它们可以是有线的（以太网NIC）或无线的（Wi-Fi NIC）。
- 使用场景：每个连接到网络的设备都有一个网络接口卡，它为计算机和网络之间提供硬件接口。
这些设备每个都在构建和管理网络中发挥着关键作用，具有针对不同网络需求和情景的特定功能。
OSI模型（开放系统互连参考模型，Open Systems Interconnection Reference Model）是一个概念模型，由国际标准化组织（ISO）创建，用于使不同的计算机系统能够通过网络进行互连。OSI模型将网络通信过程分解为七个层次，每一层都执行特定的功能，并向相邻的上层提供服务。
以下是OSI模型的七个层次，从最低层到最高层：
- 物理层（Physical Layer）
- 负责在物理媒体上传送原始的比特流。这包括定义物理设备标准、电气接口标准和传输介质。
- 例子：电缆、光纤、无线电频率。
- 数据链路层（Data Link Layer）
- 负责在相邻的节点之间传输帧，并进行错误检测和可能的纠正。它还负责流量控制和帧同步。
- 例子：以太网、无线局域网（WLAN）、PPP（点对点协议）。
- 网络层（Network Layer）
- 负责数据包从源到目的地的传递和路由选择。这一层处理数据包在网络之间的移动。
- 例子：IP协议（互联网协议）、ICMP协议（互联网控制消息协议）。
- 传输层（Transport Layer）
- 负责提供端到端的通信服务和错误恢复。它确保数据的完整性通过适当的错误检测和重传机制。
- 例子：TCP（传输控制协议）、UDP（用户数据报协议）。
- 会话层（Session Layer）
- 负责在两个系统之间建立、管理和终止会话。这层设置和维护网络中两节点的对话能力。
- 例子：NetBIOS（网络基本输入输出系统）、SSH（安全壳协议）。
- 表示层（Presentation Layer）
- 负责数据的表示、安全和压缩。它转换数据为适合接收应用程序的格式。
- 例子：JPEG、MPEG、加密协议。
- 应用层（Application Layer）
- 为应用程序提供网络服务。它直接为用户的应用程序（如电子邮件、文件传输）提供服务。
- 例子：HTTP（超文本传输协议）、FTP（文件传输协议）、DNS（域名系统）。
每一层都依赖于其下一层的功能，将其作为自己的服务提供者，并向上层提供服务。OSI模型有助于标准化交换信息的方法，从而促进了不同系统和技术之间的互操作性。
9. Role and Function of a Router
Routers transmit data packets between networks by analyzing destination IP addresses and finding optimal paths in routing tables. Routers also act as firewalls, protecting the internal network from external threats.
路由器通过分析目标IP地址并查找路由表中的最优路径，在网络之间传输数据包。同时，路由器还充当防火墙，保护内部网络免受外部威胁。
10. Ethernet and Collision Detection and Avoidance
Ethernet is a LAN technology for wired device communication. It uses the CSMA/CD protocol to detect and avoid collisions. When a collision is detected, data transmission pauses, then resends after a random delay.
以太网是一种局域网技术，用于有线设备间的通信。它使用CSMA/CD协议检测和避免冲突。当检测到冲突时，数据传输会暂停，然后随机等待一段时间后重新发送。
CSMA/CD详细介绍
CSMA/CD (Carrier Sense Multiple Access with Collision Detection) 是一种用于有线网络的协议，主要用于以太网（Ethernet）技术中。它的工作原理涉及多台设备共享同一个传输介质（如电缆）时如何减少数据包碰撞的发生。以下是 CSMA/CD 协议的工作原理和关键点：
1. 载波监听（Carrier Sense）
在设备发送数据之前，它会“监听”线路上的信号，以确保没有其他设备在传输数据。设备只有在侦听到传输通道空闲时才会进行发送。这样可以减少由于多个设备同时发送数据而导致碰撞的可能性。
2. 多路访问（Multiple Access）
所有设备共享同一个通信介质。每个设备都可以独立尝试发送数据，但是为了避免干扰，它们会遵循特定的协议规则来决定何时可以发送。
3. 碰撞检测（Collision Detection）
由于所有设备共享一个通信通道，即使进行了载波监听，碰撞仍可能发生。CSMA/CD 会在数据发送过程中检测碰撞的发生。设备会检测发送的信号是否与其他设备的信号相冲突。
4. 碰撞后的重传（Collision Recovery）
如果检测到碰撞，所有参与碰撞的设备会停止发送数据，并发送一个称为“拥塞信号”的短脉冲，让其他设备知道碰撞的发生。之后，每个设备会等待一段随机时间（称为退避时间）后再尝试重新发送数据。这个退避时间的随机化使得冲突设备不太可能再次同时尝试发送，从而减少后续碰撞的几率。
CSMA/CD 的关键步骤
- 监听信道：在发送之前，设备会检查信道是否空闲。
- 传输数据：如果信道空闲，设备开始发送数据。
- 检测碰撞：在发送数据时持续监听，判断是否发生碰撞。
- 发送拥塞信号：如果发生碰撞，所有设备暂停发送，并发出拥塞信号。
- 退避并重试：设备等待随机时间后再尝试发送数据。
优缺点
- 优点：CSMA/CD 简单易实现，不需要复杂的集中控制器。
- 缺点：随着设备数量增加，碰撞几率也增高，效率降低。此外，在无线通信环境下，CSMA/CD 不适用，因为无线环境难以准确检测碰撞。
CSMA/CD 主要用于早期的以太网局域网中（如 10Mbps 的共享电缆网络）。现代以太网通常采用交换技术，已不再使用 CSMA/CD。
Ethernet详细介绍
Ethernet is a family of wired computer networking technologies commonly used in local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). It was first developed by Xerox PARC in 1973 and has since been refined through numerous standards set by the IEEE, particularly the IEEE 802.3 series. Ethernet uses a variety of cables and connectors, including coaxial cable, twisted pair cable, and fiber optic cable.
Here are some key points about Ethernet:
- Data Transmission: Ethernet networks primarily use a packet-based transmission protocol. Each packet contains data and control information, including source and destination addresses that enable data to be delivered to the correct recipient.
- Topology: Traditionally, Ethernet networks utilized a bus or star topology, but modern Ethernet installations mainly use a star topology where each device is connected to a central switch. This reduces the chances of data collisions and improves network efficiency.
- Speed Variations: Over the years, Ethernet has evolved to support higher data rates, starting from 10 Mbps (10BASE-T), to 100 Mbps (100BASE-TX), 1 Gbps (1000BASE-T), and up to 10 Gbps (10GBASE-T) and beyond.
- Access Method: Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) as a method for devices connected to the network to check the channel for availability and manage data transmissions to avoid collisions. However, in modern Ethernet networks, where switches are predominantly used, collisions are largely avoided.
- Applications: Due to its standardization, robustness, and ease of installation, Ethernet is widely used in both office and industrial environments, supporting everything from basic data traffic to voice and video communications.
Ethernet continues to evolve, offering improvements in speed, efficiency, and the ability to handle different types of network traffic, making it one of the most enduring and crucial technologies in the field of networking.
以太网是一种常用于局域网（LAN）、城域网（MAN）和广域网（WAN）的有线计算机网络技术。它最初由施乐PARC于1973年开发，并通过IEEE的多个标准（特别是IEEE 802.3系列标准）进行了精细化改进。以太网使用多种电缆和连接器，包括同轴电缆、双绞线电缆和光纤电缆。
以下是以太网的一些关键点：
- 数据传输：以太网网络主要使用基于包的传输协议。每个数据包包含数据和控制信息，包括源地址和目的地址，这些信息确保数据能正确送达接收方。
- 拓扑结构：传统上，以太网网络使用总线或星型拓扑，但现代以太网安装主要使用星型拓扑，其中每个设备都连接到一个中心交换机。这降低了数据碰撞的几率，提高了网络效率。
- 速度变化：多年来，以太网已发展支持更高的数据传输速率，从10 Mbps（10BASE-T）到100 Mbps（100BASE-TX）、1 Gbps（1000BASE-T）以及高达10 Gbps（10GBASE-T）甚至更高。
- 接入方法：以太网使用载波侦听多路访问/碰撞检测（CSMA/CD）作为连接到网络的设备检查通道可用性并管理数据传输以避免碰撞的方法。然而，在现代以太网中，主要使用交换机，碰撞已大幅减少。
- 应用：由于以太网的标准化、稳健性和安装方便性，它广泛应用于办公室和工业环境中，支持从基本数据流量到语音和视频通信等各种通信。
以太网持续发展，提供了速度、效率和处理不同类型网络流量的能力的改进，使其成为网络领域中最持久且至关重要的技术之一。
11. Bit Streaming
Bit streaming refers to the continuous transmission of data in a bit-by-bit sequence, commonly used in real-time data applications like video and audio streaming. Its advantage is seamless, uninterrupted data flow, requiring stable bandwidth.
位流传输指的是按比特序列连续传输数据，常用于视频、音频等实时数据应用。其优势是提供无缝、连续的数据流，但需要稳定的带宽。
12. Differences Between the World Wide Web (WWW) and the Internet
The internet is a global network of connected systems providing fundamental communication infrastructure. The WWW, on the other hand, is an information-sharing system accessed via web browsers. In simple terms, the internet is the infrastructure, while the WWW is a service built on it.
互联网是全球互联系统的基础通信架构，而万维网（WWW）则是一个通过浏览器访问的信息共享系统。简单来说，互联网是基础设施，而万维网是基于此基础的服务。
13. Hardware Supporting the Internet
Internet-supporting hardware includes routers, modems, and servers. Modems connect local devices to broadband networks, routers handle data transfer between local and wide-area networks, and servers store and deliver web and application resources.
支持互联网的硬件包括路由器、调制解调器和服务器。调制解调器将本地设备连接到宽带网络，路由器管理本地和广域网之间的数据传输，服务器存储并提供网页和应用资源。
路由器、调制解调器和服务器的比较
Here's a comparison of routers, modems, and servers, focusing on their key functions and roles in a network:
Aspect | Router | Modem | Server |
Function | Directs data packets between devices on a network and to/from the internet | Converts digital data from a device into a format suitable for transmission over phone or cable lines (analog) | Provides resources or services to other devices on a network |
Primary Role | Acts as a traffic manager, ensuring data reaches the correct device | Serves as a bridge between the local network and the internet | Delivers files, applications, websites, or processing power to clients |
Location in Network | Located within a LAN or between LAN and internet (WAN) | Typically found at the boundary of a LAN and ISP’s network | Placed within a network, accessible to authorized devices only |
Connection Types | Ethernet, Wi-Fi | DSL, cable, fiber-optic, dial-up | Ethernet, Wi-Fi, or sometimes over the internet |
Data Packet Handling | Routes packets within networks based on IP addresses | Transmits and receives data between ISP and router | Processes requests and serves data to connected clients |
Can Work Standalone? | No, usually requires a modem for internet connection | No, typically paired with a router to enable network sharing | Yes, can operate independently within a network |
Summary:
- Router: Manages network traffic, enabling devices to communicate within and outside the LAN.
- Modem: Connects to the ISP, converting data for internet access.
- Server: Provides specific resources, data, or applications to other devices on the network.
以下是路由器、调制解调器和服务器的比较，重点在它们在网络中的主要功能和角色：
方面 | 路由器 | 调制解调器 | 服务器 |
功能 | 在网络中各设备之间以及网络和互联网之间转发数据包 | 将设备的数字数据转换为适合在电话线或电缆上传输的格式（模拟信号） | 向网络中的其他设备提供资源或服务 |
主要角色 | 作为流量管理器，确保数据包到达正确的设备 | 作为局域网和ISP网络之间的桥梁 | 向客户端提供文件、应用、网站或计算资源 |
网络位置 | 位于局域网(LAN)或局域网和互联网（广域网）之间 | 通常位于局域网和ISP网络的边界 | 在网络中，通常只允许授权设备访问 |
连接类型 | 以太网、Wi-Fi | DSL、电缆、光纤、拨号 | 以太网、Wi-Fi，有时通过互联网 |
数据包处理 | 基于IP地址在网络内路由数据包 | 在ISP和路由器之间传输和接收数据 | 处理请求并将数据提供给连接的客户端 |
独立运行能力 | 否，通常需要调制解调器连接互联网 | 否，通常与路由器配合以实现网络共享 | 是的，可以在网络中独立运行 |
总结：
- 路由器：管理网络流量，使设备之间及与外部互联网进行通信。
- 调制解调器：连接到ISP，将数据转换为适合互联网访问的格式。
- 服务器：在网络中向其他设备提供特定资源、数据或应用程序。
补充：ISP介绍
ISP（Internet Service Provider，互联网服务提供商）是指提供用户接入互联网并进行数据传输的公司或组织。ISP可以提供多种服务，包括宽带上网、数据托管、电子邮件服务以及安全服务等。用户通过ISP可以连接到互联网，访问网页、发送电子邮件、播放视频和下载文件等。
ISP的主要功能：
- 接入服务：ISP提供物理连接或无线连接，使用户能够接入互联网。这些服务可以是拨号上网、DSL（数字用户线）、光纤、卫星或蜂窝移动网络。
- 域名服务：ISP通常提供DNS（域名系统）服务，帮助将网络地址（如 www.example.com）转换成IP地址，这是互联网通信的基础。
- 电子邮件服务：许多ISP提供电子邮件账户和相关服务，用户可以通过这些账户发送和接收电子邮件。
- 网络安全服务：随着网络安全威胁的增加，许多ISP开始提供防病毒、防火墙、反垃圾邮件和数据加密等安全服务，以保护用户在互联网上的安全。
- 技术支持：ISP通常提供技术支持服务，帮助用户解决连接问题或其他与互联网使用相关的技术问题。
ISP的种类：
- 商业ISP：向个人用户和企业客户提供服务的商业性公司。
- 接入ISP：提供物理接入互联网的服务，如有线电视公司或电话公司。
- 托管ISP：提供服务器托管或虚拟服务器服务，企业可以在这些服务器上运行网站或其他网络应用。
- 移动ISP：通过蜂窝网络提供互联网接入服务的运营商。
ISP在全球互联网基础设施中扮演着关键角色，它们构建和维护网络连接，确保数据能够在世界各地的网络之间流动。随着技术的进步和互联网用户的增加，ISP的服务和技术也在不断进化，以满足日益增长的网络需求和安全挑战。
14. Use of IP Addresses
IP addresses identify devices in network communication, providing routes for data packet transmission. IP addresses come in IPv4 (32-bit) and IPv6 (128-bit) formats. They ensure data packets reach the correct destination device.
IP地址用于在网络通信中标识设备，并提供数据包传输路径。IP地址分为32位的IPv4和128位的IPv6，确保数据包能准确抵达目标设备。
15. Use of URL for WWW Resource Location and DNS Role
A URL locates specific resources on the WWW, consisting of protocol, domain, and path elements. DNS converts human-readable domain names (e.g., example.com) into IP addresses, making it easier for users to access resources without needing to memorize complex IP addresses.
URL用于在WWW上定位特定资源，由协议、域名和路径组成。DNS将人类易读的域名（如example.com）转换为IP地址，使用户无需记住复杂的IP地址便可访问资源。
This structure provides an English and Chinese breakdown of each key point, helping you understand the content from both language perspectives.
（ChatGPT）
三. 练习题
填空题原题
Here are 20 fill-in-the-blank questions based on the provided content:
- Networking devices such as switches, routers, and access points enable efficient and reliable __________ within a network.
- Answer: data exchange
- A __________ typically covers a limited geographical area and offers fast transmission speeds with low latency.
- Answer: LAN (Local Area Network)
- A __________ connects over large areas, possibly internationally, and typically has higher latency and slower transmission speeds than a LAN.
- Answer: WAN (Wide Area Network)
- In the client-server model, __________ are the endpoint devices that request resources, while the server provides them.
- Answer: clients
- In a __________ network, devices can act as both clients and servers, sharing resources without centralized control.
- Answer: peer-to-peer (P2P)
- __________ clients rely heavily on servers for processing tasks, while thick clients can operate more independently.
- Answer: Thin
- In a __________ topology, devices are connected to a central node, making it reliable but vulnerable if the central point fails.
- Answer: star
- A __________ topology connects each device to multiple others, providing redundancy but often at a higher cost.
- Answer: mesh
- Cloud computing provides on-demand access to resources over the __________, which helps reduce hardware maintenance costs.
- Answer: internet
- Wireless networks allow connections without __________, making them ideal for mobile environments.
- Answer: physical cabling
- A __________ is used to connect segments of a LAN, allowing data to flow between them.
- Answer: bridge
- A __________ analyzes destination IP addresses to forward data packets between different networks.
- Answer: router
- Ethernet uses the __________ protocol to detect and avoid data collisions within a LAN.
- Answer: CSMA/CD
- __________ is the continuous transmission of data bits, commonly used in real-time applications like audio and video streaming.
- Answer: Bit streaming
- The internet is a global network of connected systems, while the __________ is a system of interlinked information accessible via web browsers.
- Answer: World Wide Web (WWW)
- Devices connect to networks via a __________, which establishes the physical connection between the device and the network.
- Answer: Network Interface Card (NIC)
- A __________ converts human-readable domain names into IP addresses, allowing users to access websites without needing to remember IP addresses.
- Answer: DNS (Domain Name System)
- IP addresses identify devices in network communication and come in __________-bit (IPv4) and __________-bit (IPv6) formats.
- Answer: 32; 128
- A __________ specifies the location of a specific resource on the World Wide Web, often including the protocol, domain, and path.
- Answer: URL (Uniform Resource Locator)
- A __________ connects local devices to broadband networks, allowing access to wider area networks such as the internet.
- Answer: modem
- 作者:现代数学启蒙
- 链接:https://www.math1234567.com/article/communication
- 声明:本文采用 CC BY-NC-SA 4.0 许可协议，转载请注明出处。