Switches and Hubs - What is the difference?

The two most common network devices used to connect end-points with each other are hubs and switches. The purpose of installing these devices in a network is to provide connectivity between the end-points, printers, servers and any other network resources. Apart from this common usage of both hubs and switches, there is a significant difference between the working and implementation of both these devices. This article will enable you to understand the differences between hubs and switches and will also briefly explain their working.

Hubs

A hub is a physical layer (Layer-1) network device which is used to connect several ethernet devices together to form a single network segment. A network segment has one broadcast domain and one collision domain.

A broadcast domain is a segment of the network where the data sent by any end-point is accessible by all other end-points connected to that network.

Similarly, a collision domain is a segment of the network where the data sent by any end-point can collide with the data sent by the other end-points. Having a single broadcast domain and a single collision domain makes hubs prone to excessive data collisions and very less security.

There is a bandwidth limitation on hubs as the bandwidth is shared between the end-points, as the number of devices connecting to a particular hub increases, the bandwidth decreases and the data collision increases.

Hubs are unmanaged and dumb network devices, there is no software installed on a hub that manages the flow of data, you can use the hub right out of the box as it does not need to be configured. Because of non-manageability, hubs are typically used in home networks or small office networks.

Switches

A switch is a data-link layer (Layer-2) network device which is primarily used for the same purpose as a hub. A switch can be split into several broadcast domains using Virtual Local Area Network (VLAN) technology. A VLAN is a group of switch ports that are defined by the switch’s software as one broadcast domain. In case of a VLAN, the data transmitted by any end-point is only accessible to the members of that VLAN rather than all the end-points connected on that switch. A layer-3 device (Switch or Router) is required to communicate among the different VLANs.

All the ports of a switch are part of a distinct collision domain, so in case of a 24 port switch, there are 24 distinct collision domains. Collisions are considerably less in switches as they are only possible if a hub is connected to a switch port.

Switches are available as managed switches and un-managed switches. Un-managed switches do not require any configuration and can be used as a plug-and-play device. The managed switches are used to gain deeper control over the switch’s performance and security parameters. Large enterprises and corporate offices use managed network switches.

Layer-3 switches are also available, these switches work on the network layer of the OSI model and can perform routing functions. Using layer-3 switches eliminates the need to using a router to perform inter-VLAN routing.

Table 1 shows the basic comparison between a switch and a hub:

Feature

Hub

Switch

Layer

Layer-1

Layer-2 and Layer-3

Manageability

Un-Managed

Managed

Data Transmission

Bits

Frames or Packets

Device Type

Passive (W/O Software)

Active

Transmission Mode

Half-Duplex

Full-Duplex

Broadcast Domains

1

1 or More

Collision Domains

1

Equal to No. of Ports

Table 1: Comparison of Hubs and Switches

Conclusion

In light of the above details, it can be reasoned that the hubs are used in smaller and less critical networks where one can compromise on the speed, efficiency and security of the network. The main advantage of using hubs is cost savings and ease of installation. On the other hand, switches require skilled staff for its management but provide reliability, efficiency, higher speeds and increased security of the network environment. Now a days, hubs are almost obsolete, un-managed network switches have replaced the hubs in small offices and homes, whereas managed switches are being used in almost every enterprise, government and corporate office.