Network connection equipment

Repeater: Repeater is used to solve the problem of cable length. It can amplify the transmitted signal so that it travels further on the network. The advanced repeater can expand the transmission distance of the medium by amplifying and reproducing the signal.

Hub: Its role can be simply understood as connecting some machines to form a LAN.

Switch: (also known as switching hub) The role is almost the same as the hub. However, there is a difference in performance: the hub uses the shared bandwidth to work, and the switch is the exclusive bandwidth. In this way, when the number of machines or data is large, the two will be more obvious.

Bridge: It works at the data link layer, connecting two local area networks (LANs) and forwarding frames based on MAC addresses (physical addresses). It can be seen as a "low-level router" (routers work at the network layer, according to the network Addresses such as IP addresses are forwarded). It can effectively connect two LANs, local communication is limited to this segment, and the corresponding signal is forwarded to another segment. Bridges are usually used to connect a small number of network segments of the same type.

Router: To explain the concept of a router, first of all, what is a route? The so-called "routing" refers to the act and action of transferring data from one place to another, and the router is the machine that performs this action. Its English name is Router. A network layer device that uses one or more metrics to determine the best path through which network traffic can pass. The router forwards packets from one network to another based on network layer information. Occasionally also known as the gateway (although this definition of the gateway has now passed). It is one of the essential network devices in the Internet. A router is a network device that connects multiple networks or network segments. It can “translate” data information between different networks or network segments to make them Can mutually "read" each other's data, thus forming a larger network. The router has two typical functions, namely data channel function and control function. Data channel functions include forwarding decisions, backplane forwarding, and output link scheduling. Generally, they are implemented by specific hardware. Control functions are generally implemented in software, including information exchange with neighboring routers, system configuration, and system management. .

Gateway: In the early days of the Internet, the term gateway refers to a router. A router is a mark in the network that goes beyond the local network. This "gateway" to the unknown is still used to calculate routes and forward packet data outside the source network. Therefore, it is considered to be the gateway to the Internet. . Over time, routers are no longer magical, and the advent and maturity of public IP-based WANs has facilitated the growth of routers. Now that the routing function can also be performed by the host and the switching hub, the gateway is no longer a mystical concept. Nowadays, the router becomes a multifunctional network device. It can divide the LAN into several network segments, interconnect the related LANs in the private wide-area network, and interconnect the wide-area networks to form the Internet. In this way, the router loses the original gateway. concept. However, the term gateway is still in use. It is continuously applied to many different functions. Defining the gateway is no longer an easy task.