What is the difference between a switch and a router?

Many weak friends think that these two are used to access the Internet. As for what difference they have, it is not clear what is going on. What is the difference between a switch and a router?

What is the difference between switches and routers?

Switch and router difference

One of the differences

A router can automatically assign IP to your LAN. Virtual dialing, like a traffic*, directs where your computer should go, and you don't have to worry about that much. The switch is only used to distribute network data.

The difference between the two

Routers are at the network layer, routers are addressed based on IP addresses, routers can handle TCP/IP protocols, and switches cannot.

The switch is at the relay layer and the switch is addressed based on the MAC address.

The difference between the three

A router can assign an IP address to many hosts. These hosts only show one IP address. A switch can connect many hosts. Each of these hosts has its own IP address.

The fourth difference

The router provides the service of a firewall. The switch cannot provide this function. Hubs and switches are all port extensions, which is to expand the access points of LAN (usually Ethernet), that is, to allow LAN to connect more computers. Routers are used to make inter-network connections, which are used to connect different networks.

The difference five

For example: The router is equivalent to the post office, and the letter is delivered to the recipient's address, and its task is completed. However, the letter arrived at your dormitory building, and this address is not exclusive to you. Therefore, the uncle Wang of the building management is also responsible for giving you the letter. He does not care about the address of the recipient but only looks at the recipient's name. , and then make an inside call to get you a letter.

If you don't have a post office, you can't send letters to pretty girls all over the world, and you can't receive letters from pretty girls outside the building. However, because of the existence of uncle Wang of the building management, you can still communicate with his good friends with the dormitory building.

The system formed by all post offices is the "wide area network", and your dormitory is the "local area network". Building a local area network does not require a router.

The difference between Layer 3 switches and routers

Although they all have routing capabilities.

However, the main function of the three-layer switch is still data exchange, and its routing function is usually relatively simple, because it is mainly facing a simple LAN connection, the routing path is not as complicated as the router, it is mainly used in the LAN Provides fast data exchange functions to meet the frequent application features of LAN data exchange.

The main function of a router is a routing function. Its routing function is more reflected in the interconnection between different types of networks, such as the connection between a local area network and a wide area network, the connection between different protocols, and so on, so the router is mainly used. Between different types of networks. Its main function is routing forwarding. It is its ultimate goal to resolve the connection of various complicated routing path networks. Therefore, the routing function of routers is usually very powerful. It is applicable not only to LANs of the same protocol, but also to different protocols. LAN and WAN. Its advantages lie in choosing the best route, load sharing, link backup and exchange of routing information with other networks and so on. In order to connect with various types of networks, the interface types of the routers are very rich, and the three-layer switches are generally only the same type of LAN interface, which is very simple.

Technically speaking, routers and Layer 3 switches have significant differences in packet switching operations. Routers typically perform packet switching by a microprocessor-based software routing engine, while Layer 3 switches perform packet switching through hardware. After the Layer 3 switch routes the first data flow, it will generate a mapping table of MAC address and IP address. When the same data flow passes through again, it will pass through the table directly instead of re-routing according to the table. This eliminates network delays caused by router routing and improves packet forwarding efficiency. At the same time, the routing lookup of Layer 3 switches is for data flow. It uses caching technology and is easily implemented using ASIC technology. Therefore, it can greatly save costs and achieve fast forwarding. The router's forwarding uses the longest matching method and is complex to implement. It is usually implemented using software and the forwarding efficiency is low.

Because of this, compared to the overall performance, the performance of Layer 3 switches is much better than that of routers, which is very suitable for LANs with frequent data exchanges. However, although routers have very powerful routing functions, its packet forwarding efficiency is much lower than that of routers. Layer 3 switches are more suitable for the interconnection of different types of networks where data exchange is not very frequent, such as the interconnection of LANs and the Internet. If routers, especially high-end routers, are used in LANs, this is a waste (in terms of their powerful routing capabilities) to a great extent, and it still cannot meet the LAN communication performance requirements well, affecting subnets. In view of the above-mentioned normal communication, it is preferable to use a three-layer switch in a multi-subnet connection in a local area network, especially in environments where data exchange between different sub-networks is frequent. On the one hand, it can ensure the communication performance requirements between subnets, on the other hand, it eliminates the need to purchase additional switches. Of course, if the communication between sub-networks is not very frequent, the use of routers is understandable. It is also possible to achieve the purpose of securely isolating the communication between sub-networks. The specific needs to be determined according to actual needs.

The biggest difference between Layer 3 switching and routing is that the routing supports nat conversion, and Layer 3 does not support it. It is reflected in the actual project: the direct connection to the optical fiber on the router can be used to access the Internet, and connecting the optical fiber to the layer 3 device cannot access the Internet. Each of the three layers has a dedicated mac address and has a dedicated ASIC integrated circuit.

The difference between network switches and routers

A network switch is an equipment that expands the network and can provide more connection ports in the subnetwork to connect more computers. With the development of the communications industry and the advancement of the national economy informatization, the network switch market has been steadily rising. It has the characteristics of high cost performance, high flexibility, relatively simple, and easy to implement. Therefore, Ethernet technology has become the most important LAN networking technology today, and network switches have become the most popular switch.

A router is a device that connects LANs and WANs in the Internet. It automatically selects and sets routes based on the conditions of the channel, and sends signals in the order of the best route. The router is the hub of the Internet, "traffic *". Currently, routers have been widely used in various industries, and products of various grades have become the main force for achieving various backbone network internal connections, backbone network interconnections, and interconnection between backbone networks and the Internet. The main difference between a router and a switch is that the switch occurs in the second layer of the OSI reference model (data link layer), and the routing occurs in the third layer, the network layer. This difference determines that routing and switches need to use different control information in the process of moving information, so the way the two implement their respective functions is different.