What is the difference between a bridge, a router, and a gateway?

成都亿佰特

What is the difference between a bridge, a router, and a gateway? [Copy link]

Bridges, routers and gateways are three important types of network devices. In the OSI model, they are located at different levels.
Bridges: Work at the second layer of the OSI model, the data link layer. The main function of the bridge is to forward and filter frames based on the MAC address. When a frame arrives at the interface of the bridge, the bridge not only copies the frame to all other interfaces, but also checks the second layer destination address of the frame and tries to forward the frame to the interface leading to the destination address. Bridges have now been phased out, and modern switches (such as Ethernet switches) are similar in function to bridges.
Routers: Work at the third layer of the OSI model, the network layer. The main function of a router is to forward packet data through the network layer. Routers can process data based on IP addresses, and they can connect two different data links, such as connecting two Ethernets.
Gateways: Also called protocol converters because they can support conversion between different protocols. Gateways are located in various layers of the OSI model and can achieve conversion between different link layer, session layer, presentation layer and application layer protocols as needed. Generally speaking, gateway is a concept and does not refer to a specific device. Any device that can achieve the above functions is called a gateway. A gateway can be a router, a switch, or even a computer.

Bridges, routers and gateways have different functions and characteristics in computer networks. Here are their differences:
1. Working level:
Bridges work at the data link layer, execute the data link layer protocol, and are responsible for transmitting data between two adjacent devices.
Routers work at the network layer, execute the network layer protocol, and are responsible for routing data packets between multiple networks. Gateways work
above the network layer, usually execute the transport layer protocol, and are responsible for data transmission and protocol conversion between different networks.

2. Data processing method:
Bridges overcome physical limitations when interconnecting, which means that the total number of data stations and network segments that make up a LAN can be easily expanded. It can effectively connect two LANs, limit local communication within the network segment, and forward corresponding signals to another network segment.
Routers use the ID numbers (i.e. IP addresses) of different networks to determine the address for data forwarding.
The main function of a gateway is to connect two completely different networks. In the Internet, two networks must also be interconnected through a computer called a gateway.
3. Function:
Bridges can effectively connect two LANs, limit local communication within the network segment, and forward corresponding signals to another network segment. Therefore, they are usually used to connect a small number of network segments of the same type. The
main function of a router is routing, that is, determining the best path for forwarding data packets. At the same time, it also has the functions of isolation and filtering, which can limit network traffic and prevent unnecessary communication.
The main function of a gateway is protocol conversion and data transmission. It can connect networks with different protocols together to achieve communication between networks with different protocols.
In general, bridges, routers, and gateways have different functions and characteristics in computer networks. Users need to choose suitable devices according to their needs and network structure when networking.

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cyberlogic

Damn, good analysis.

damiaa

The bridge works at the data link layer, executes the data link layer protocol, and is responsible for transmitting data between two adjacent devices.

The main functions of a gateway are protocol conversion and data transmission. It can connect networks with different protocols together and realize communication between networks with different protocols.

lkh747566933

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