什么是交换机（网络）？
Switch is a network device or function which mainly used to switch frames or packets into different transmission mediums or cables. Traditional switches work in the OSI Layer 2 and switch frames according to the source and destination addresses into different ports. The switch is a crucial part of a computer network. Even switch can provide different protocol support in most of the cases switch is closely coupled with the Ethernet protocol and the term switch is mostly used to express the Ethernet Switches. Even switch history goes back to the 1960s the modern ethernet switch is created in 1990 by Kalpana.
Switch是一种网络设备或功能，主要用于将帧或数据包切换到不同的传输介质或电缆中。 传统的交换机在OSI第2层中工作，并且根据源地址和目标地址将帧切换到不同的端口。 交换机是计算机网络的关键部分。 在大多数情况下，即使交换机也可以提供不同的协议支持，但交换机与以太网协议紧密相关，术语“交换机”通常用于表示以太网交换机。 甚至交换机的历史可以追溯到1960年代，现代的以太网交换机由Kalpana于1990年创建。
开关功能和特性 (Switch Functions and Features)
In the first years, the switch was used for a single function in order to switch frames between different ports but with the advancement of the switch they provided more features and functions. Below we will list some of the most popular and useful functions and features of the switches.
在最初的几年中，交换机用于单一功能，以便在不同端口之间切换帧，但是随着交换机的发展，它们提供了更多的功能。 下面我们将列出一些最流行和有用的开关功能。
Packet/Frame Switching is the main function and features of the switch. Switch have multiple ports and switch a incoming packet/frame to the destination port.
Packet/Frame Switching是Packet/Frame Switching的主要功能。 交换机具有多个端口，并将传入的数据包/帧切换到目标端口。
Increase Signal is functioned by connecting mutiple switches where packet or frame signal will be created and increased in each switch.
通过连接多个交换机来运行Increase Signal功能，在每个交换机中将创建并增加数据包或帧信号。
Security can be configured according to the different parameters and technologies like MAC address, Port number, VLAN, etc.
可以根据不同的参数和技术(例如MAC地址，端口号，VLAN等)配置Security 。
Bonding will merge the bandwidth of the two or more physical ports like a single logical port which will increase the bandwidth.
Bonding将合并两个或多个物理端口的带宽，例如单个逻辑端口，这将增加带宽。
Bandwidth Management for set limits abut upload and download bandwidth for specific port.
设置限制的Bandwidth Management毗邻特定端口的上载和下载带宽。
开关类型 (Switch Types)
With the new features and functions different types of switches are created. Below you can find differen types of switches.
通过新的特性和功能，可以创建不同类型的开关。 您可以在下面找到不同类型的开关。
Unmanaged Switches provides basic features with no or little management capabilities. They are plug and play which means there is no need for configuration for work. Unmanaged Switches are used in for personal or small office environments.
Unmanaged Switches提供的基本功能几乎没有管理功能。 它们是即插即用的，这意味着无需进行工作配置。 非管理型交换机用于个人或小型办公室环境。
Managed Switches provides intermediate level switch features like serial console, telnet or SSH access, SNMP, VLAN, STP, etc with the web-based management interface. Managed switches are the most popular switch type in the enterprise environment.
Managed Switches通过基于Web的管理界面提供中级交换机功能，例如串行控制台，Telnet或SSH访问，SNMP，VLAN，STP等。 受管交换机是企业环境中最流行的交换机类型。
Smart Switches are between Unmanaged and Managed switches which provide a basic web interface for management with less capability and features.
Smart Switches位于非托管和托管交换机之间，它们以较少的功能和特性为管理提供了基本的Web界面。
Enterprise Managed Switches are the high-level switches which provide a full set of management capabilities and features like CLI, SNMP agent, web interface, config backup and restore, stacking, load balancing, and availability.
Enterprise Managed Switches是高级交换机，可提供全套管理功能，如CLI，SNMP代理，Web界面，配置备份和还原，堆叠，负载平衡和可用性。
开关组件(Switch Components)
Swithces consist of multiple components like mainboard, ports, power supply etc.
开关由主板，端口，电源等多个组件组成。
Mainboard is the main component where other components are connected and the switching function and operation are executed. Network ports transmit received frame/package to the mainboard and the mainboard decides the switching operation which port will be used. Also, switch firmware and software runs on the mainboard of the switch.
Mainboard是连接其他组件并执行开关功能和操作的主要组件。 网络端口将接收到的帧/数据包发送到主板，然后主板决定将使用哪个端口进行交换操作。 另外，交换机的固件和软件在交换机的主板上运行。
Network Port is the most important part of a switch where the hosts or computers connects to the switch via this ports. Generally RJ45 type plugins are used for Ethernet protocol connection between switch and computer. Cable is CAT-5 or CAT-6 type. In some cases for uplink port fiber can be used with different connectors like SFP, SFP+ etc.
Network Port是交换机最重要的部分，主机或计算机通过该端口连接到交换机。 通常，RJ45类型的插件用于交换机和计算机之间的以太网协议连接。 电缆为CAT-5或CAT-6型。 在某些情况下，上行链路端口光纤可以与SFP，SFP +等不同的连接器一起使用。
Management Port is a port used to manage and configure switch. Management port can be a serial port or Ethernet port but generally used with RS238 protocol.
Management Port是用于管理和配置交换机的端口。 管理端口可以是串行端口或以太网端口，但通常与RS238协议一起使用。
Power Supply i used to provide power to the switch and its components.
Power Supply我曾经用来为交换机及其组件供电。
Firmware or Software is used to run different functions as software for switching, management, protocol operations.
Firmware or Software用于运行各种功能，如用于交换，管理，协议操作的软件。
交换机与集线器 (Switch vs Hub)
Switches can be compared hubs where both of them provide very same physical look. But their function is a bit different.
可以将交换机与集线器进行比较，它们在这两个集线器上都提供非常相似的外观。 但是它们的功能有些不同。
- The switch checks the source or destination address of the package but Hub does not make a check. 交换机会检查软件包的源地址或目标地址，但集线器不会进行检查。
- The switch provides extra and advanced features where the hub is a dummy with no features devices. 该交换机提供了额外的高级功能，其中集线器是一个没有功能设备的虚拟设备。
- The switch provides high-level performance where hub performance is very low especially in high traffic network environments. 该交换机在集线器性能非常低的地方提供了高级性能，尤其是在高流量网络环境中。
- The switch is more secure than a hub where hub provides easy access to network traffic for attackers. 交换机比集线器更安全，在集线器中，集线器可以使攻击者轻松访问网络流量。
交换机与路由器 (Switch vs Router)
Switch and Router are different devices with different functions. Actually they complete each other for an enterprise-level network. Below we will compare the switch and router for similarities and differences.
交换机和路由器是功能不同的不同设备。 实际上，它们在企业级网络中相互完善。 下面我们将比较交换机和路由器的异同。
- Generally, the switch has a lot more network ports than a router. 通常，交换机比路由器具有更多的网络端口。
- Generally switch works on Layer 2 where router works on Layer 3. 通常，交换机在第2层上工作，而路由器在第3层上工作。
- The switch is used for packet/frame switching on single network LAN where Router is used to route packets in different networks. 该交换机用于在单个网络LAN上进行数据包/帧交换，其中路由器用于在不同网络中路由数据包。
- Generally switch is cheaper than a router. 通常，交换机比路由器便宜。
- Switches provide fewer features than routers. 交换机提供的功能少于路由器。
第2层交换机与第3层交换机 (Layer 2 Switch vs Layer 3 Switch)
In networking, there are two terms Layer 2 Switch and Layer 3 Switch. As we know switch works on Layer 2 according to the OSI reference model. But with the advancement of the networking devices and different needs, some switch are created with basic routing or Layer 3 features. These switches with Layer 3 or routing capabilities are called Layer 3 Switches. Layer 2 Switch is a standard and normal switch with switching related capabilities.
在网络中，有两个术语第二层交换机和第三层交换机。 众所周知，交换机根据OSI参考模型在第2层上工作。 但是随着网络设备的发展和不同的需求，一些具有基本路由或第3层功能的交换机就被创建了。 这些具有第3层或路由功能的交换机称为第3层交换机。 第2层交换机是具有交换功能的标准和普通交换机。