It’s very much possible to create a computer network based only on hubs, but there are a few reasons why this is not recommended, despite the fact they’re cheaper than switches. Switches are essentially the same as hubs, but just a little bit smarter. This article discusses the small difference between hubs and switches, as well as the benefits that using switches instead of hubs brings.
Hubs are widely thought of as dumb peices of networking equipment. They do their job of forwarding information across a network, but that’s all they’re capable of doing. The way they forward information is very wasteful, in terms of adding traffic onto the network. If you have 10 PC’s connected to a 10 port hub and the PC connected to port 1 wants to talk to the PC connected to port 5, the hubs’ only option is to broadcast the information down all of the ports, so every PC is sent the information despite it only being addressed to the PC on port 5. You can see how wasteful this is.
A switch is slightly different, they are more intelligent; the switch maintains a table, called an ARP table (Address Resolution Protocol) of all PC’s connected. The table cross references each port on the switch with the hardware address, also known as the MAC address, of the device connected to that port. Using the example above, if the PC on port 1 wants to talk to the PC on port 5, it sends the information to the switch including the MAC address of the PC on port 5, the switch then looks up the location of the the PC based on the ARP table and the MAC address provided; the switch knows to forward the information to port 5 only. This uses up less resources and creates less traffic on the network.
Sure you could have a small network of 10 PC’s running perfectly fine using a hub, but that’s missing the point. As a network grows, the more important it becomes to manage the amount of traffic on the network. This is a fundamental concept of network design. We should understand from this that a network design based on hubs suffers from poor scalability. Another benefit of using switches instead of hubs is that they virtually eliminate collisions; a collision occurs when two computers try to transmit information on the same wire at the same time, both sets of information are lost because they crash into each other. The bigger the hub based network, the more likely that collisions are going to happen, everything else being equal. When information is lost due to collisions, the two computers have no choice but to resend the lost information, which means that it’s likely to take longer sending a piece of information using a hub rather than a switch.
There we have it, switches take less time to transmit information when compared to a hub, they use less resources, create less network traffic, are more intelligent and far more scalable. So when your boss asks you to look into networking all the PC’s within your company together, you can explain the many reasons why it’s worth spending a little bit more and going with switches.