Hubs, Switch, Routers — What are they?
Hubs, switches and routers are network devices that help in the routing of data packets. This blog is a brief explanation untangling the three of them and to hopefully get a clearer picture of they function in a network.
Hub
One of the simplest (and extinct) network devices is the hub. The only function of the hub is to connect multiple LANs (Large Area Network) devices together by relaying a message/signal it has received to all the ports (PCs or LAN devices). The hub works at OSI (Open Systems Interconnection) layer 1. The switch has now replaced the hub almost completely because although cheap, it is still not cheaper than the switch. As discussed ahead the switch has better functionality than the hub.
Switch
Switches or bridges create a network of devices that share resources. Like the hub, it connects multiple LAN components together. A switch can also reduce the collisions in a shared channel.
There are 3 types of switches:
- Unmanaged (layer 2) switch: multiport switch
- Managed (layer 2) switch
- Managed (layer 3) switch: multilayer switch
Managed vs. Unmanaged Switches
Unmanaged switches do not need to be configured. They are plugged in and they are good to go. They are usually used in small networks whose needs are very basic. Unmanaged switches start forwarding traffic immediately after the switch is plugged in and basically have no other functionality like network security capabilities. However, they are cheaper than managed switches.
On the other hand, a managed switch needs an administrator of sorts to be configured because it is customisable. It is suitable for a much larger network. Managed switches are configured to give a wide range of capabilities regarding network performance and network safety.
Routers
Routers connect these LAN networks to other LAN networks to each other and to the internet. The two main functions of the router are: managing traffic between these networks by forwarding data packets to their intended IP addresses and allowing multiple devices to use the same internet connection.
How do routers work?
Let a data packet be an aeroplane, this will make the network traffic to be the air traffic. In this context, the router will work as an air traffic controller. Each aeroplane has a unique, predefined destination and an air traffic controller needs to ensure that each aeroplane lands at its designated airport without getting lost or colliding with each other. In the same way, a router, a router guides data packets to their correct IP addresses. To ensure this, it uses internal routing tables which are just a list of paths to all the network destinations. The address of the destination is mentioned in the header of the data packet which is read by the router. It then determines the path that is most efficient from the routing table and forwards it to the next network in the path.
