Is the router shared bandwidth shared by N computers? Is the switch an equal bandwidth for N compute

To get to know them, let's talk about hubs and switches. The hub works at the first layer (i.e. the physical layer), it has no intelligent processing power, for it, the data is just current, when the current from one port reaches the hub, it simply sends the current to the other ports, and as for the computer connected to the other ports to receive this data or not, it doesn't care. The switch works at the second layer (i.e. the data link layer), it is smarter than the hub, for it, the data on the network is a collection of MAC addresses, it can distinguish the source MAC address and the destination MAC address in the frame, so it can establish a connection between any two ports, but the switch does not know the IP address, it only knows the MAC address.

The router works in the third layer (that is, the network layer), it is more "smart" than the switch, it can understand the IP address in the data, if it receives a packet, it checks the IP address in it, if the destination address is the local network ignores it, if it is another network, it will take the packet out of the local network. So to understand how they work, that is, to know that they are actually all sharing broadband, but the routing has packet exchange packet filtering, and all the ports belong to different broadcast and collision domains. Whereas, the switch does not have the function of packet switching and filtering, all ports share a broadcast domain, and each port is a collision domain.

The router treats n computers as a whole (intranet) and connects them to the external network through a single access to the main bandwidth, which is a softswitch (so it sometimes crashes). The switch (which you specify should be below Layer 2 and does not have the routing function) belongs to circuit switching, which is equivalent to the broadband connection of N computers to the external network.

When multiple terminals share links, they will inevitably affect each other. "Do not affect each other" is just a legend, or only under certain conditions the approximate existence of "mutual non-influence" situation, this condition is that the sum of the allowable bandwidth of multiple terminals is lower than the shared link bandwidth, for example, 10 2M terminals allow bandwidth to share 100M link, it can be approximated that the terminals "do not affect each other" (refers to the bandwidth, not the logical link, the logical link does not affect each other is implemented by the frame header The header mechanism is implemented, that is, the MAC header is used in the second layer and the IP header is used in the third layer. It is not directly related to bandwidth).

It should be pointed out here that the "line bandwidth" is not the physical bandwidth of the line medium, and the fact that CAT provides 100M link bandwidth in a 100M Fast Ethernet architecture does not mean that the physical bandwidth of CAT is 100M, an obvious example is that Gigabit CAT patch cords also work at 100M bandwidth in a 100M Fast Ethernet architecture, not a 1000M link.

Let me explain it to you in more layman's terms:

Networks communicate according to certain rules. For example, if a 6-lane road is wide enough and only 5 cars are passing in parallel or in the opposite direction, as long as they are driving according to traffic laws, it will not be affected. The same is true for the network, which has its own conflict detection mechanism.

As long as the line bandwidth can meet the communication requirements, it will not be affected. This mechanism is negotiated by the devices involved in the two ends of the communication. It's like when you're overtaking on the highway and changing lanes to turn signals.

Of course, if your actual data is larger than the line can carry, it will definitely affect. Just like a one-way street, you have to go in the wrong direction, and a two-lane road, you have to have three cars in the same row.

Why do they affect each other?

The highway is nearly infinitely wide (for a general network).