选择合适的网络交换机

你可以选择一个unmanaged switch如果你的网络不是很复杂而且您可以将所有端口打开，而无需隔离其中任何一个。如果您只需要连接一些设备彼此并将其连接到互联网这些网络交换机可能是一个不错的选择低购买价格。这种类型的网络交换机通常是即插即用，即，您只需将其连接以使其运行。

如果您不知道您的网络如何进化，您也可以选择一个托管网络交换机并留下默认配置。此配置可能很有趣，因为它消除了如果在稍后演变的情况下，它会消除重建网络的需要，因为受管网络交换机允许您根据您的需求远程管理和修改网络。这种类型的网络交换机很好managing a complex network, but it requires the skills of a network engineer to monitor port security, access control lists (ACLs) and bandwidth allocation. Some network switches are equipped with an API (Application Programming Interface), which makes it possible to do IaC (infrastructure as code).

如果您想保留对网络的控制，但它仍然相对简单，您也可以选择一个智能开关这通过在线界面部分管理。这些网络交换机是一个good compromise between an unmanaged switch and a managed switch。根据您选择的型号，您可以访问适用于管理VoIP手机的服务质量（QoS）或虚拟网络（VLAN）等选项，或者希望能够将网络部分隔离其他提高网络安全性和性能。

以太网网络使用可能不同的传输速度，具体取决于要求：
网络为10 Mbps（megabits per second) are generally used for email and intranet networks. The equipment is wired on RJ45 sockets.
网络of 100 Mbps（称为快速以太网）专为小型文件传输而设计（每个文件最多150 MB）。该设备在RJ45插座上有线。
网络1000 Mbps（Gigabit Ethernet) are used for large files such as video files (more than 150 MB per file). The equipment is wired on RJ45 sockets.
网络为10 GB / s（10.GBASE-T) are the current standard for the installation of new corporate networks.
For very large data transfers or long distances between different devices, you might want to look into光纤转移技术（100GB / S：100gbase-SR4,100 m，或100g或100gbase-lr4，高达40公里）。设备通过SFP模块接线。

For industrial networks, there are alsofieldbusessuch as PROFIBUS, PROFINET, CAN or ControlNet that allow the data transfer between sensors, actuators and PLCs.

根据应用程序的网络示例：

• 有关数据采集：传感器需要具有专用端口的受管交换机。
• 对于控制系统：PLC的控制和命令需要在环形拓扑中增加冗余。为确保冗余，必须使用具有至少100 Mbps的吞吐量的交换机。
• Backbone: starting at 100 PLCs, you must use a main ring, called a backbone, which interconnects switches by optical fiber. The equipment is then distributed by 100 Mbps over ring wireline sub-networks on copper cables.
• 视频监控：从20个摄像机开始，您将需要千兆以太网的专用网络。选择用PoE（以太网电源）网络为电机为电池供电是有利的。

The number of ports available on your network switch is essential because it determines the number of devices that can be connected to it. A network switch can accommodate from 2 to 64 ports. In order to choose the switch that best suits your requirements, you will need to determine how many devices you are going to connect and whether this number is likely to change in the short to medium term.
Some network switches are equipped with a stack plug that allows switches to be connected to each other, thus increasing the number of available ports.

Network switches are integrated in casings designed to be installed either in electrical cabinets or in standard bays:

• Ethernet switches for small networks are usually equipped with a DIN rail mounting system, which is standard for integrating different equipment into a normal or electrical cabinet.
• In larger networks, switches are designed to beintegrated into racksand in this case their size is indicated in 19-inch rack occupancy units in a cabinet (i.e. a switch occupies 1U, or the width of a 19-inch rack for a height of 1.75 inches). The 19-inch rack corresponds to standard dimensions (in Europe DIN 41494).
• 如果您有很少的设备连接到网络交换机，可以将其留在设备附近的桌子上，但您必须小心噪声水平，因为交换机的端口越多，它将越响亮。

In order to choose the right network switch, you must take into account the evolution of network management and the increasing number of connectable and connected devices:

• 可编程的网络（软件定义的网络或SDN）：此架构可提高网络控制，并启用对更改业务需求的快速响应。此架构需要受管交换机，因为它们由集中式SDN控制器管理。
• 物联网（IoT): the number of connected objects is changing rapidly and you will need to take this future evolution into account when sizing your network so that it does not quickly become obsolete.

您还可以在市场上找到第3层网络交换机，以充当具有更大端口的路由器。