A network switch is a networking component device that is mainly used as a central point to connect multiple devices within a network. A network switch is intelligent in such a way that it is possible to identify the destination address of the message and direct it to that device instead of broadcasting. They operate at the data link layer (layer 2) on the Open System Interconnections (OSI) model.
The main types of network switches are managed, smart, PoE, and unmanaged. They are used to forward packets within the same network and they use MAC addresses to identify the source and destination of packets. Switches help manage devices on a network. However, they are expensive and for the advanced managed device they require an expert to configure.
Types network switch
This is the most advanced type of switch. It offers network administrators more features to control and manage networks. They are mostly used in larger organizations to manage many devices on the network.
They can operate are layer 2 or layer 3 of the OSI model. For layer 2 they forward packets using the MAC address while for layer 3 they use the IP address.
They can be used to create VLAN, port aggregation, and quality of service settings among others.
They also manage switches but they offer less advanced features compared to a fully managed switch. They are more powerful and offer more features than unmanaged switches.
Unmanaged network switches
This is a basic switch that offers more ports to connect more devices to the network. They are mostly plug-and-play. This means you don’t need to make a configuration to start using them. You just power the device and connect to the network for it to start operation.
Power over Ethernet (PoE) switches
These are switches that use the same cable to transmit data to the device and power them at the same time. This means if the switch support PoE then you can connect devices such as CCTV camera using the same ethernet cable for power and data. They reduce the number of cables used and device power consumption.
How networking switch works
When the switch is connected to the network for the very first time it doesn’t have any record on the MAC address table (CAM) table. It needs this table populated to use it to forward packets to different destinations.
When a computer sends packets for the first time it reaches the switch and it is broadcasted to all ports connected to the switch. The respective device gets the packet then the switch now keeps MAC addresses for both destination and source devices on the network.
It continues like that until all the connected ports are assigned a MAC address on the CAM table.
Next time the packet is sent to any device the switch check for the address on the table and it sends the packet directly to that device instead of broadcasting the message to all ports.
Functions of network switch
- Maintain a MAC address table called Content Addressable Memory (CAM) table. This is for switches that operate at layer 2 of the OSI model. They use this table to determine the destination and source address of the message.
- PoE switches power devices such as CCTV cameras, Access Points, and other low-power devices.
- They support full-duplex communication which means data can move on both sides faster.
- Network switches are used to connect different devices within the same local network. It works as a central point connection mostly to create a star topology type of network layout.
Advantages of using a network switch.
- They simplify network management by centralizing the management to the switch.
- The switch offers additional security features and can be used to implement VLAN which separates different ports on the same switch.
- By using a switch each device has a dedicated connection which reduces packet collision challenges. This improves the speed and overall performance of the network.
- A network designed with a switch is simple to expand since the number of devices that can be connected is only limited to the number of ports on the switch.
Disadvantages of switch
- The switches are expensive to acquire.
- Networks are mostly used to connect devices within the same network. So they are limited only to LAN networks.
- Advanced switches like managed are complex to configure and they require a specialist.
- It creates a single point of failure. When the switch fails the whole network fails.
- Switches require regular maintenance to keep them working optimally.
Difference between network switch vs hub
A network hub is also used as a central point device to connect devices to the same network. However, unlike the switch, when a message is sent from one device to another is broadcasted to all ports.
The recipient of the message checks the address and acts accordingly. With the switch, the message is directed to the specific destination address and not broadcast.
Difference between a switch and a network router.
Both network devices are used to forward packets to the device. However, the network router operates at layer 3 while the switch operates at layer 2 of the OSI model.
Router used an IP address to forward the packet to different types of networks which use different protocols. Switch on the other hand forward packets within the same LAN network and use the MAC address to determine the destination address.