Lesson,Networking hardware,What do you know about networking hardware? Have you heard anything about OSI model?,Warm-up Exercises,data packet 数据包 allocate 分配 segment 段 hub 集线器 broadcast domain 广播域 collision domain 冲突域 topology 拓扑结构 bandwidth 频宽 repeater 中继器, 转发器,Word Preparation,All these terms refer to devices facilitating the use of a computer network. Specifically, they mediate data in a computer network. Gateway: this device is placed at a network node and interfaces with another network that uses different protocols. It works on OSI layers 4 to 7. Router: a specialized network device that determines the next network point to which it can forward a data packet towards the ultimate destination of the packet. Unlike a gateway, it cannot interface different protocols. It works on OSI layer 3.,所有这些术语都涉及那些帮助运用计算机网络的设备,专用的网络设备通过向原先数据包的目的地发送一个数据包决定了未来网络指向, Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s) which connect the segment to another network segment. Unlike a hub, a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. It works on OSI layer 2. Bridge: a device that connects multiple network segments along the data link layer. It works on OSI layer 2., Hub: a device that connects multiple Ethernet segments, making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time. Depending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc.). It provides bandwidth which is shared among all the objects, in contrast to switches, which provide a connection between individual nodes. It works on OSI layer 1. Repeater: a device which amplifies or regenerates digital signals received while sending them from one part of a network into another. It works on OSI layer 1.,采用集线器的时候，每一个连接设备都享有相同的广播域和冲突域。,依赖于网络的拓扑结构，集线器在网络对象诸如工作站、服务器等之间提供了基本的1级OSI模型连接。,The Open Systems Interconnection (OSI) model (ISO/IEC 7498-1) is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar communication functions are grouped into logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path. Two instances at one layer are connected by a horizontal connection on that layer.,OSI,Questions,According to the text, how many devices facilitate the use of a computer network? Whats the function of a router? How many computers connected to the hub are able to transmit at a time?,Translate the following sentences into Chinese,This device is placed at a network node and interfaces with another network that uses different protocols. It works on OSI layers 4 to 7. Unlike a hub, a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. It works on OSI layer 2. It provides bandwidth which is shared among all the objects, in contrast to switches, which provide a connection between individual nodes. It works on OSI layer 1,Simple writing,Please describe the devices facilitate the use of a computer network., THANK YOU！ ,