Types of Switches in Computer Network - GeeksforGeeks (2024)

Switches in computer networks are devices that connect multiple devices (like computers, and printers) within a network. They manage data traffic efficiently by directing data only to the devices that need it, enhancing network performance. Unlike hubs, switches operate at the data link layer (Layer 2) of the OSI model, making decisions based on MAC addresses. They are crucial for creating reliable and fast local area networks (LANs).

Switches are the connectivity points of an Ethernet network. These are small devices that can receive data from multiple input ports and send it to the specific output port that takes data to its intended destination in the network.

Characteristics of a Switch

Before we dive into different types of switches, let’s understand some key features of a switch:

• In a switch, two important things to know are its “poles” and “throws.” A pole is where an electrical contact is made, and a throw is how many different contacts each pole can connect to. The number of poles and throws tells you how the switch works and what it can connect to in a circuit.
• In switches, you often find two standard types: Single, which has one contact point or one connection, and Double, which has two contact points or two connections. These terms describe how switches are built and what they can do in electronic devices.
• If a switch has more than two poles or throws, we usually just state the number directly. For example, a switch with three poles and six throws is called a “3P6T” switch.
• Momentary switches, like push buttons, make contact only while they are pressed. They’re used for brief actions or as long as you hold the button.
• Latched switches, on the other hand, maintain their contact position until they are switched to the other position.

Types of Switches in Computer Network

There are different types of switches in a network. These are:

• Mechanical Switches
  • Single Pole Single Throw Switch (SPST)
  • Single Pole Double Throw Switch (SPDT)
  • Double Pole Single Throw Switch (DPST)
  • Double Pole Double Throw Switch (DPDT)
  • Toggle Switch
  • Limit Switch
  • Pressure Switches
  • Temperature Switches
  • Joystick Switch
  • Rotary Switches
• Electronic Switches
  • Power Diode
  • MOSFET
  • SCR
• Managed Switches
  • Smart Switches
  • Enterprise-Managed Switches
  • LAN Switches
  • PoE Switches
• Unmanaged Switches
• Layer 2 Switches
• Layer 3 Switches

Mechanical Switches

Mechanical switches are physical switches that you activate by physically moving, pressing, releasing, or touching their contacts. Mechanical switches come in different types depending on things like how they are activated (manual, limit, or process switches), how many contacts they have (single or multi-contact switches), the number of poles and throws (like SPST, DPDT, SPDT), their design and operation (push button, toggle, rotary, joystick), and whether they are momentary or locked.

Some important mechanical switches are discuss below:

Single Pole Single Throw Switch (SPST)

• This is a simple ON and OFF switch that has one input contact and one output contact.
• It controls a single circuit, either allowing current to flow (ON) or stopping it (OFF).
• The SPST switch can have contacts that are normally open (not connected in the default state) or normally closed (connected in the default state).

Single Pole Double Throw Switch (SPDT)

• This switch has three terminals: one is the input contact and the other two are output contacts.
• It has two ON positions and one OFF position.
• Typically, these switches are used to alternate between two outputs for a given input.
• The contact that is connected to the input by default is called the normally closed contact, and the contact that is connected during the ON operation is called the normally open contact.

Double Pole Single Throw Switch (DPST)

• This switch has four terminals: two are input contacts and two are output contacts.
• It functions like two separate SPST switches that work simultaneously.
• There is only one ON position, but both switches can activate their respective contacts at the same time, connecting each input to its corresponding output.
• When in the OFF position, both switches are open.
• These switches are used to control two different circuits simultaneously.
• The contacts of this switch can be either normally open or normally closed configurations.

Double Pole Double Throw Switch (DPDT)

• This is a dual ON/OFF switch with two ON positions.
• It has six terminals: two input contacts and four output contacts.
• It works like two separate SPDT switches operating at the same time.
• In one position, the two input contacts are connected to one set of output contacts. In the other position, the input contacts are connected to the other set of output contacts.

Toggle Switch

• A toggle switch is manually operated using a handle, lever, or rocking mechanism. It’s often used to control lights.
• These switches typically have multiple positions for their levers, such as SPDT, SPST, DPST, and DPDT.
• They can handle high currents, up to 10 amps, or small currents.
• Toggle switches come in various ratings, sizes, and styles for different applications.
• The ON position can be at any lever position, but conventionally, the downward position is considered ON or closed.

Limit Switch

• They are designed to operate based on the presence or absence of objects, or the movement of machinery rather than human hand operation.
• These switches use a bumper-type arm that reacts when an object makes contact with it. When this happens, it triggers a change in the position of the switch contacts.

Pressure Switches

• These switches are widely used in industrial settings to monitor the pressure of hydraulic and pneumatic systems.
• Depending on the pressure range they measure, they are classified into diaphragm-operated, metal bellow, and piston-type pressure switches.
• In all these types, a pressure sensing element triggers a set of contacts, which can be either double-pole or single-pole.
• The symbol for these switches features a half-circle connected to a line, with the flat part.
• They can be configured as normally open or normally closed switches.

Temperature Switches

• The most common heat sensing element is the bimetallic strip, which works by utilizing thermal expansion.
• Bimetallic strips are made by bonding two metals with different rates of thermal expansion.
• When temperature changes, the strip bends or warps, activating the switch contacts.
• Another method uses a mercury glass tube: as the bulb heats up, the mercury inside expands, creating pressure that triggers the switch contacts.

Joystick Switch

• Joystick switches are handheld control devices used in portable equipment. They have a lever that moves in multiple directions.
• When you move the lever, it activates one or more switch contacts.
• Joysticks are great for controlling movements like up, down, left, and right.
• They’re commonly used in machinery, cable controls, and cranes.

Rotary Switches

• These switches are used to connect one line to several others.
• They’re found in electrical meters (for range selection), communication devices (for channel selection), and multi-band radios (for band selection).
• These switches come in various configurations like single pole 12-way, 3-pole 4-way, 2-pole 6-way, and 4-pole 3-way, depending on the number of poles (lines connected) and throws (ways to connect)
• They have a knob (moving contact) that connects with multiple fixed contacts.

Electronic Switches

Electronic switches operate differently from mechanical switches because they don’t need physical contact to control a circuit. Instead, they use semiconductor technology to activate and deactivate. Electronic switches are often referred to as Solid State switches because they lack physical moving parts and therefore have no physical contacts. Semiconductor switches, such as transistors, SCRs, MOSFETs, TRIACs, and IGBTs, are commonly used to control various appliances like motor drives and HVAC equipment. These solid state switches come in different types and sizes, catering to consumer, industrial, and automotive needs with varying ratings.

Power Diode

• A diode can switch between two states: a high impedance state and a low impedance state. These states control how easily electricity can pass through it.
• Diodes are made from semiconductor materials like Silicon and Germanium. For power diodes, Silicon is commonly used because it can handle higher currents and temperatures at the junction where the materials meet.
• A diode is created by joining together two types of semiconductors: p-type and n-type. This junction is called a PN junction.
• A diode has two parts, the anode and the cathode, which are its two terminals. These terminals determine how electricity flows through the diode, allowing it to control current in electronic circuits.

MOSFET

• The MOSFET is a very popular semiconductor device used for switching in electronics. It’s called a Metal Oxide Semiconductor Field Effect Transistor. It’s known for being unipolar, meaning it uses only one type of charge carrier, and it can switch on and off very quickly, even at high frequencies.
• In electronic power applications, the MOSFET is the go-to choice. It has three important parts: the drain (where the output goes), the source (which is the common connection), and the gate (where you give it commands).

SCR

• A Silicon Controlled Rectifier (SCR) is a high-speed switching device commonly used for power control applications. It operates as a unidirectional switch similar to a diode, with three terminals: anode, cathode, and gate.
• To turn an SCR ON or OFF, you control its gate input and adjust the biasing conditions between the anode and cathode terminals.
• The SCR is structured with four layers of alternating P (positive) and N (negative) semiconductor materials. The boundaries between these layers form junctions labeled as J1, J2, and J3. These junctions play a critical role in the SCR’s operation and switching characteristics.

Managed Switches

These types of switches have many features like the highest levels of security, precision control, and full management of the network. These are used in organizations containing a large network and can be customized to enhance the functionality of a certain network. These are the most costly option but their scalability makes them an ideal option for a network that is growing. They are achieved by setting a simple network management protocol(SNMP).

Advantages

• Control over network traffic.
• Enhanced security and performance.
• Remote management and monitoring capabilities.

Disadvantages

• More expensive than unmanaged switches.
• Requires technical expertise to set up and configure.

Types of Managed Switches

Smart Switches

These switches offer basic management features with the ability to create some levels of security but have a simpler management interface than the other managed switches. Thus they are often called partially managed switches. These are mostly used in fast and constant LANs which support gigabit data transfer and allocations. It can accept the configuration of VLANs (Virtual LAN).

Enterprise-Managed Switches

They have features like the ability to fix, copy, transform and display different network configurations, along with a web interface SNMP agent and command-line interface. These are also known as fully managed switches and are more expensive than smart switches as they have more features that can be enhanced. These are used in organizations that contain a large number of ports, switches, and nodes.

LAN Switches

These are also known as Ethernet switches or data switches and are used to reduce network congestion or bottleneck by distributing a package of data only to its intended recipient. These are used to connect points on a LAN.

PoE Switches

PoE switches are used in PoE technology which stands for power over Ethernet that is a technology that integrates data and power on the same cable allowing power devices to receive data in parallel to power. Thus these switches provide greater flexibility by simplifying the cabling process.

Unmanaged Switches

These are the switches that are mostly used in home networks and small businesses as they plug in and instantly start doing their job and such switches do not need to be watched or configured. These require only small cable connections. It allows devices on a network to connect such as a computer to a computer or a computer to a printer in one location. They are the least expensive switches among all categories.

Advantages

• Simple to install and operate.
• Inexpensive

Disadvantages

• Lack of control over network traffic.
• Limited security and performance.

Layer 2 Switches

These are the most common type of switches used in local area networks (LANs). They operate at the data link layer (Layer 2) of the OSI model and are used to connect devices within a network, such as computers, printers, and servers. Ethernet switches forward Ethernet frames based on MAC addresses.

Advantages

• Fast and efficient traffic forwarding.
• Can help reduce network congestion.

Disadvantages

• Limited control over network traffic.
• No support for Layer 3 protocols.

Layer 3 Switches

These switches combine the features of traditional Layer 2 Ethernet switches with routing capabilities found in routers. They can make forwarding decisions based on IP addresses as well as MAC addresses, allowing them to route traffic between different subnets or VLANs (Virtual Local Area Networks).

Advantages

• Advanced routing capabilities.
• Network segmentation.
• Increased performance and scalability.

Disadvantages

• More expensive than Layer 2 switches.
• Requires technical expertise to configure and managed.

Top 5 Uses of a Network Switch

When setting up network switches, IT managers should keep these use cases and applications in mind:

• Connect with multiple hosts simultaneously.
• Offload network traffic: reduce the amount of data that travels through a network by diverting some of it to alternative paths or methods.
• Optimize LAN bandwidth: improve the efficiency of data transfer within a local area network to ensure faster and smoother communication between devices.
• Populate the MAC address table: fill in the table that maps MAC addresses to their corresponding network ports, enabling the network switch to efficiently forward data to the correct devices.
• Enable MAC filtering and other access control features: activate settings that allow a network device to permit or deny connections based on the MAC addresses of devices trying to access the network, enhancing security and control over network access.

Conclusion

In computer networks, there are different types of switches for different needs. Ethernet switches are common for connecting devices within a local network, while Layer 3 switches add routing capabilities between subnets. Managed switches offer control and security features, whereas unmanaged switches are simpler and cost-effective. PoE switches provide power over Ethernet cables, and industrial switches are designed for rugged environments. Each type of switch plays a vital role in ensuring efficient and reliable network operations based on specific requirements.

Frequently Asked Questions on Different Types of Switches – FAQs

What is an Ethernet switch?

An Ethernet switch is a device that connects multiple devices in a local area network (LAN) and forwards data based on MAC addresses.

What is the difference between a Layer 2 switch and a Layer 3 switch?

A Layer 2 switch operates at the data link layer and forwards traffic based on MAC addresses. A Layer 3 switch operates at both the data link layer and the network layer (IP layer), allowing it to perform routing functions between different subnets or VLANs.

What are managed switches used for?

Managed switches provide administrators with control over network traffic, security features, VLAN configuration, Quality of Service (QoS), and monitoring capabilities.

What are PoE switches used for?

PoE switches deliver power over Ethernet cables to devices like IP phones, wireless access points, and security cameras, simplifying installations by eliminating the need for separate power cables.

See Also

Cisco Switch Selector