What is a router? How does it work and what are its features? Is it okay not to install it?

To explain the principle simply, we can only use an analogy: a router is compared to a logistics company's delivery center, and data is compared to a cargo. The role of the router is like that of a logistics company, identifying the ** address and sending address of the goods (data), and transferring the goods (data) from one place to another.

Whether you install a router or not depends on your needs. If you only have one computer in your home, then you don't need a router, and if you have several computers in your house that need to be connected to the Internet at the same time, you need a router. Its characteristics are relative to professional network technology, if you don't understand network technology, you don't need to understand its characteristics, just plug in the power supply and use it.

The router can divide a network broadband into several and connect them to several different computers, so that the computers can access the Internet at the same time, and it is okay not to install it, but only one can be on Thank you, I hope.

Traditionally, routers work at Layer 3 of the OSI Layer 7 protocol, and their main task is to receive packets from one network interface and decide to go to the next destination based on the destination address contained in it. Therefore, the router first has to find its destination address in the ** routing table, and if the destination address is found, it will add the next MAC address before the frame grid of the packet, and at the same time, the TTL (Time to Live) domain of the IP packet header will also start to subtract and recalculate the checksum. When a packet is delivered to the output port, it needs to wait sequentially before it can be delivered to the output link.

When the router is working, it is able to look up the routing table in the device according to a certain routing communication protocol. If there is more than one path to a particular node, the basic predetermined routing criterion is to choose the optimal (or most economical) transport path. Since the various network segments and their interconnection may change due to changes in the environment, the information on the routing situation is generally updated regularly according to the provisions of the routing information protocol used.

In the network, the basic function of each router is to dynamically update the routing table it maintains according to certain rules to maintain the validity of routing information. In order to facilitate the transmission of packets between networks, routers always break down large data into packets of appropriate size according to predetermined rules, and then send these packets through the same or different paths. After these packets arrive at their destinations in order, the decomposed packets are packed into the original packet form in a certain order.

The hierarchical addressing function of the router is one of the important functions of the router, which can help the network with many node stations to store the addressing information, and can also intercept the packets sent to the remote network segment between the networks, which plays a leading role; Choosing the most reasonable route and guiding communication is also the basic function of the router; Multi-protocol routers can also connect network segments that use different communication protocols and become a communication platform between network segments with different communication protocols.

A router is a network that connects multiple logically separated networks, and a logical network represents a single network or a subnet. When data is transferred from one subnet to another, it can be done through a router. Therefore, router has the function of judging network address and selecting path, it can establish flexible connection in multi-network interconnection environment, can connect various subnets with completely different data packets and media access methods, router only accepts the information of origin station or other routers, belongs to a kind of interconnection device of network layer.

It doesn't care about the hardware devices used by the subnets, but it requires software to run that aligns with the network-layer protocols. Routers are divided into local routers and remote routers, and local routers are used to connect network transmission media, such as optical fiber, coaxial cable, and twisted pair; The remote router is used to connect the remote transmission medium, and requires the corresponding equipment, such as the ** line to be equipped with a modem, and the wireless to be through the wireless receiver and transmitter. The router principle works as follows:

1) Workstation A sends the address of Workstation B to Router 1 in the form of a data frame along with the data information. (2) After the router 1 receives the data frame of workstation A, it first takes out the address from the packet header and calculates the optimal path to workstation B according to the path table: R1->R2->R5->B; and send the data frame to Router 2.

3) Router 2 repeats the work of Router 1 and gives the data frame ** to Router 5. (4) Router 5 also takes out the destination address, finds that it is on the network segment connected to the router, and then directly hands the data frame to workstation B. (5) Workstation B receives the data frame of Workstation A, and a communication process is declared to be over.

In fact, in addition to the main function of routing mentioned above, the router also has a network traffic control function. Some routers only support a single protocol, but most routers can support the transmission of multiple protocols, that is, multi-protocol routers. Since each protocol has its own rules, the algorithm of multiple protocols to be completed in one router is bound to reduce the performance of the router.

As a result, we thought that routers that support multiple protocols would have relatively low performance. When you buy a router, you need to select the router with the network protocol you need based on your actual situation. In recent years, there have been switching router products, which are not really new technologies, but in order to improve communication capabilities, the principle of the switch is combined into the router to make the data transmission capacity faster and better.

The router receives the packet, extracts the destination IP address and subnet mask to calculate the destination network address.

If you can't find it, see if there is a default route, and if there is, send it to the next router according to the exit of the default route;

If it is not found, send an error ICMP packet to the source IP, indicating that the packet cannot be delivered;

If the route is direct, the route is sent to the destination site based on the Layer 2 MAC address.