Network Switch – Functions, Comparison With Hub, Types & Layered Switches

A network switch, like a hub, is a small device that is used to connect devices to a network. A switch primarily acts as a controller. It allows different devices to communicate with each other efficiently. If you have read about hubs, you would know that hubs are now widely being replaced by network switching technology owing to their better performance.

To understand how a network switch is more efficient than a hub, we have to look at the problems faced by a hub and how network switches solve them.


Problems with using a hub

A hub is designed to transfer data between connected computers without any real understanding of what is being transferred. When a hub receives data from a connected device, it transmits the packet via broadcasting.

In broadcasting, the data is sent to all the connected devices without caring for the actual destination of the data. This is workable when hubs are installed on a private network.

However, in public networks, this poses a serious risk of security breach. Due to broadcasting, hubs distribute bandwidth equally between all the computers connected to it.

So, as the number of devices increases, bandwidth per device decrease leading to lower connection speed. This is irrespective of how much bandwidth a computer requires.

How is a network switch better than a hub?

Network switches work differently than hubs. Hubs operate at layer 1 (physical layer) of OSI model while switches work at layer 2 (data-link layer) of the OSI model.

Instead of broadcasting receives packets to all the connections, it determines the physical address of destination device from the packet and transmits the packet only to that device.

Switches identify the destination device using their MAC (Media access control) address. This is an intelligent way to keep the bandwidth reserved for the device that needs it. Switches come with firmware, installed by the manufacturer, which allows them to carry out the necessary task.

A firmware is a piece of software or code that provide instructions on how the device should function.

The latency of a network switch

The efficiency of use of switch comes with a trade-off. It takes time for a switch to decide the destination of a packet. This time gap is called latency, and it is the price paid for the flexibility they provide in the network.

Using network switches in homes

In the past, network switches were an expensive piece of hardware. They were also confusing and hard to use for most users. This made users opt for hubs. However, the newer models of switches are much cheaper and easy to use.

This coupled with their efficiency in data transmission has made switches very popular, widely replacing hubs in both home and office network. These days, most home and small business routers come with built-in switches.

Types of network switches

Unmanaged Switch

An unmanaged switch allows Ethernet devices to communicate with each other. These come with a fixed configuration which cannot be changed. These types of switches are also called “plug and play”.

Managed Switch

A managed switch allows a lot of more control over the network traffic. Using a managed switch, one can prioritise the certain type of data traffic ensuring that most important information gets transmitted.

They also use protocols such as SNMP (Simple Network Management Protocol). SNMP queries can determine the health of the network of the status of a particular device.

The ability to manage devices remotely helps in repairing network related problems promptly as the engineer doesn’t have to visit the site of the switch.

Managed switches also support VLAN (virtual local area network). VLAN refers to the logical group of a network. This allows for creating subgroups within a single LAN such that traffic for one subgroup is not passed to the other subgroup.

Managed switches are expensive than unmanaged switches, but with the additional services, they are a good investment for a large organisation.


Layer 3 or multi-layer network switches

A traditional network switch is layer 2 switch since they work in layer 2 data link layer of OSI model. Whereas, layer 3 switches are a mix of conventional switches and routers.

Layer 3 switches are required on large LANs where they improve the network routing performance. A layer 3 switch does not have WAN port since they are meant for LAN or local intranets.


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