先决条件 – 网络设备
1.开关：
Switch 是一个带有缓冲器的多端口桥接器，其设计可以提高其效率和性能。它是一个数据链路层设备。交换机可以在转发数据之前执行错误检查，这使得它非常高效，因为它不会转发有错误的数据包，而是选择性地将好的数据包仅转发到正确的端口。换句话说，交换机划分了主机的冲突域。
2. 网关：
网关是将两个网络连接在一起的通道，可以在不同的网络模型上工作。它基本上充当系统之间的信使代理，从一个系统获取数据，对其进行解释并将其传输到另一个系统。它也称为协议转换器。它可以在任何网络层运行。它比开关更复杂。
交换机和网关的区别：
| SWITCH | GATEWAY |
|---|---|
| It works as multi-port bridge between networks. | It works as a passage between two networks. |
| It works in data link layer. | It works in all networks layers. |
| It performs error checking before forwarding packets. | It does not perform error checking. |
| It does not work as protocol converter. | While it works as protocol converter. |
| Packet filtering is provided in switch. | Packet filtering is not provided in gateway. |
| It is less complex. | It is more complex than switch. |
| It connects devices that work on same network model. | It connects two networks working on different models. |
| The format of packet is not changed. | Packet format is changed. |