What is the difference between a hub and a switch, and a router, it s really confusing, please solve

The hub does not have a switch** function, the information received from one port is broadcast from all other ports, and the hub only acts as a signal amplification.

Strictly speaking, a switch has only Layer 2 functions, which are based on MAC address packets. After receiving packets from a port, query the port corresponding to the destination MAC address and send the packet from that port. At the same time, write the source MAC address of the packet to the MAC address of the port where the packet is received.

This is because it already knows that the host corresponding to the source MAC is connected to the port where the packet was received. In the future, when receiving packets destined for MAC address, only the port that receives the packets is sent.

The router looks up the routing table based on the IP address ** packet and sends it from the lookup to the outbound interface of the router. The routing table is calculated by routing protocols such as OSPF.

Many of today's switches also have routing functions, so such switches are called routing switches. To put it simply, a routing switch is a simple collection of routers and switches that can use both MAC address packets and IP packets.

For more information, please refer to it.

Hubs --- act like power strips to provide multiple network cables in series.

The switch --- includes the functions of a hub and can optimize network data transmission to achieve the fastest and shortest path through. (For example, if multiple switches are connected in parallel and the network structure is complex, the switch will choose the optimal (shortest, or smoothest) path to transmit data according to the situation.) )

The router --- includes hub functions and switch functions, and provides software features such as DHCP firewall PPPoE to make it more powerful and useful.

A hub is a first-tier device that cannot divide the collision domain and the broadcast domain, while a router is a layer-3 device that can divide the collision domain and the broadcast domain.

Hub: No chips, few ports.

Switches: There are chips, and there are a lot of ports.

Router: There is a chip, and the number of ports is average.

Hubs have been eliminated for many years and have been completely replaced by switches;

The router has a switch inside it, which is much more powerful than the switch

Router = network dial-up + shared Internet + switch.

At a glance, three sentences are done.