What are the common network connectivity devices?

The variety of network devices is vast and growing by the day. The basic network devices are computers (whether they are PCs or servers), hubs, switches, bridges, routers, gateways, network interface cards (NICs), wireless access points (WAPs), printers, and modems. Repeater A repeater is the simplest device for interconnecting LANs. Working at the physical layer of the OSI architecture, a repeater receives and recognizes network signals, then regenerates the signals and sends them to other branches of the network. To ensure that a repeater works correctly, it is first necessary to ensure that the packet and logical link protocols are the same in each branch. For example, between an 802.3 Ethernet LAN and an 802.5 Token Ring LAN, a repeater will not enable them to communicate. However, repeaters can be used to connect different physical media and transmit packets across a variety of physical media. Some multiport repeaters are much like multiport hubs in that they can connect different types of media. Repeaters are the cheapest way to extend a network. Repeaters are considered when the purpose of expanding a network is to break through distance and node limitations, and when none of the connected network branches generate much data traffic and the cost cannot be too high. The number of network branches connected using repeaters is limited by the specific network architecture. Repeaters do not have isolation and filtering capabilities, and they cannot block packets containing anomalies from traveling from one branch to another. This means that a failure in one branch can affect every other branch of the network. A hub is a repeater with multiple ports. Abbreviation HUB Bridge (Birdge) Bridges work at the data link layer of the OSI system. Therefore, the information in the layers above the data link layer of the OSI model is useless to the bridge. So the understanding of the protocol depends on the respective computer. A bridge contains the functions and features of a repeater, which not only connects multiple media, but also connects different physical branches, such as Ethernet and Token Networks, and is able to transmit data packets over a wider area. Typical applications for bridges are to reduce bottlenecks in data transmission by segmenting a LAN into subnets; such bridges are called "local" bridges. Bridges used on WANs are called "remote" bridges. Both types of bridges perform the same function, but use different network interfaces. In life, a switch is a bridge. Router A router operates at the network layer of the OSI architecture, which means that it can exchange and route data packets across multiple networks. Routers accomplish this by exchanging protocol-specific information across relatively independent networks. More than a bridge, a router not only filters and segregates the flow of network information and connects network branches, but also accesses more information in packets. And it is used to improve the efficiency of packet transmission. The routing table contains network address, connection information, path information and sending cost. Routers are slower than bridges and are mainly used to interconnect WANs or WANs with LANs. Bridge Router (Brouter) A Brouter is a merger of a bridge and a router. Gateway A gateway repackages information for the purpose of adapting it to the requirements of the target environment. A gateway can interconnect dissimilar networks. A gateway reads data from one environment, strips it of its old protocols, and repackages it with the protocols of the target network. One of the more common uses of gateways is to translate between microcomputers and mini- or mainframes on a LAN. A typical application for a gateway is a network private server. Firewall In networking equipment, a hardware firewall. Hardware firewall means that the firewall program is made inside the chip, and the hardware performs these functions, which can reduce the burden on the CPU and make the routing more stable. Hardware firewall is an important barrier to secure the internal network. Its safety and stability are directly related to the safety of the whole internal network. Therefore, daily routine checks are very important to ensure the security of the hardware firewall. Many hidden dangers and faults in the system will appear one way or another before the outbreak of the seedling, the task of routine inspection is to find these security risks, and as far as possible to locate the problem, to facilitate the resolution of the problem.