What is Switching in Networking?

Introduction

Switching is not a new concept in data communication. Since the early days of telephony, switching has been part of communication where operators manually connected calls via switchboards. As time passes, so do technological advancements, and with the growth of data networks, switching now has become more automated. But what do you mean by switching in networking?

Switching is a process of transferring data packets from one device to another in a network using specific devices called switches. In this blog, we will be explaining switching, its types, and the different techniques used in the process of switching.

Let’s first understand what switching really is.

What is Switching in Networking?

Data packets are transferred utilizing switches from one network to another or from one device to another during the process of switching. A switch is a piece of hardware that operates at the OSI model’s data link layer, i.e., layer 2. Incoming data packets from a source device or network are largely handled by a switch, which also selects the best port through which the data packets will go to their destination device or network.

A switch uses the destination MAC (Media Access Control) address to determine which port a data packet should travel through. Every network interface card (NIC) in a device is given a specific identification number called a MAC address.

Switching in networking is mainly divided into two parts. These are:

• Connectionless: With connectionless switching, there is no need for a dedicated path or any prior agreement between the source and the destination. In this, the data is divided into smaller components known as packets, which are transmitted individually on the basis of the destination address.
• Connection-oriented: In contrast to connectionless switching, connection-oriented switching first requires a dedicated path or a prior agreement between the source and the destination. Once the dedicated path is set, data is sent in the form of a continuous stream of bits or bytes. Afterwards, Data is transmitted along the same path by switch.

We have a better understanding now of what is switching and its types. But the question that arises now is What is a Switch and how does the switch works. Below, we have explained the switching process in detail.

What is a Switch?

A switch connects devices in a network to each other which allows them to communicate by exchanging data packets. These can be hardware devices that maintain the physical network or software-based virtual devices. The switch executes at the data-link layer, or Layer 2, of the OSI model and looks at the MAC addresses in the LAN via Ethernet to determine where to share each incoming message frame. Switches maintain tables that correspond to each MAC address of the port receiving the MAC address.

How Does Switch Work?

The switch generally involves the following steps:

• Reception of Frames: A device connected to the switch’s ports sends a data frame or packet to the switch.
• Extraction of MAC Addresses: The destination MAC address is retrieved by the switch by reading the data frame’s header.
• MAC Address Table Lookup: The switch searches its switching table after obtaining the MAC address to locate a port that connects to the MAC address of the data packet.
• Forwarding Decision and Switching Table Update: At this stage, the switch starts matching the destination MAC address of the frame to the MAC address in its table. If a case arises where the destination MAC address does not match or exists in the table in the forwarding table, it starts the flooding process. In this process, the switch starts sending the data frame to all of its ports except the one the frame came from. After this, the switch records all the MAC addresses to which the frame was delivered. With the help of this, the switch can easily find the new MAC address and update it accordingly in its forwarding table.
• Frame transition: Once the destination port is found, the switch sends the data frame to that port and forwards it to its target device/network.

Process of Switching

The switching process includes the following steps:

• Frame Reception: The switch receives a data frame or packet through a computer connected to its port.
• MAC Address Extraction: The switch examines the header of the data frame and gathers the destination MAC address from it.
• MAC Address Table Lookup: Once the switch recovers the MAC address, it runs a lookup in its switching table to identify the port that leads to the MAC address of the data frame.
• Forwarding Decision and Switching Table Update: The switch forwards a data frame to a port when it matches the frame’s destination MAC address with the MAC address in its switching table. However, it follows a flooding process in which it shares the data frame on all its ports except the port from which it came and records all the MAC addresses to which the frame was delivered when the destination MAC address does not exist in the forwarding table. Through this approach, the switch gets the new MAC address, and its forwarding tables are updated.
• Frame Transition: The switch shares the data frame on that port and forwards it to its target computer when the destination port is detected.

Why is Switching Required?

Here are the following reasons that define why switching is needed:

• Bandwidth: It refers to the maximum transmission rate of the cable and is an essential and expensive resource. Therefore, switching is required to utilize the bandwidth of the network effectively.
• Collision: It means that impact occurs when more than one device shares messages on the same physical media, and they collide with each other. That is why, to solve this problem, switching is required through which packets do not collide with each other.

Let’s understand the different types of switching techniques in detail.

Types of Switching Technique

Switching techniques are methods of implementing switching in networking. Mainly, there are three types of switching techniques that are commonly used in data communication. These are:

Circuit Switching

Circuit Switching is a type of connection-oriented switching technique. It means that it establishes a physical or logical path between the source and the destination prior to sending any message. A circuit here is defined as a dedicated channel that transmits data continuously. It can be either permanent or temporary.

As you can see in the image below, a circuit switch network with 4 switches connected to each other.

Some examples of circuit switching in networking are Analog telephone networks, PSTN (Public Switched Telephone Networks), and many more.

Packet Switching

Packet switching is a type of connectionless or connection-oriented switching technique that divides the message into units of variable length known as packets, each of which is given a source and destination address. Without buffering or sequencing, the switches independently forward the packets.

Depending on the network configuration and the availability of pathways, the packets may travel different paths to reach their destination. The packets are put back together by the destination device to form the original message. Packet switching is suitable for applications that require efficient and flexible communication, such as web browsing or streaming.

Packet switching is further classified into two, i.e., Datagram switching and virtual circuit switching.

• Datagram packet switching: It is also known as connectionless switching; it means that no connection is made before data sharing occurs, and it treats each data frame as an individual unit, and thus, it Is carried forward separately. Even though this approach provides flexibility in data transmission, it may suffer from loss of data frames or late delivery of data frames.
• Virtual-circuit packet switching: It is also known as connection-oriented switching; it means that a logical connection is established between the source and destination before any data is shared, and these logical connections are called virtual circuits. In this approach, each data frame follows these logical paths and offers an efficient way of sharing data without the risk of data loss.

Message Switching

Message switching is a type of connectionless switching technique that stores and transmits data units as a whole message. The message is divided into fixed-length units, also known as blocks. These blocks are assigned with the sequence number as well as the destination address. Until the switch finds the path to the next switch or the destination device, the blocks are stored in buffers.

Once the blocks reach the destination, the destination device reassembles the block into the original message. Here, messages can be of any size and format. This type of switching technique is suitable only for applications that do not require real-time communication. Some of the examples are email, file transfer, and many others.

We now have a better understanding of the switching and its types. We also have discussed different switching techniques. Let’s discuss the advantages and disadvantages of switching in networking.

Advantages of Switching

Some of the advantages of switching in networking are:

• It reduces network congestion by means of dividing the network into segments.
• It also assists in enhancing the network performance.
• It enhances network security by isolating the traffic of different devices. This will further prevent any access to user data.
• It enables QoS (quality of service) by prioritizing the traffic based on various factors. Some of these are the source or destination of the data and type.
• It also helps in achieving scalability. As it can easily add new switches without affecting the topology.

Disadvantages of Switching

Here are some disadvantages of Switching –

• Switching in networking can be expensive. These are more costly than hubs and repeaters.
• Switching can create network loops. If there are multiple paths available to the destination, it might create network loops.
• It can also introduce latency.

These are the advantages and disadvantages of Switching in Networking.

Frequently Asked Questions

Q1 – What do you mean by switching network?

The transmission of data packets or blocks across a network switch is known as switching in information technology and computer networking. Switches transmit data from source ports on computers and other devices to destination ports on routers and other devices.

Q2 – What are the methods of switching?

Mainly, there are three methods of switching. These are:

• Store-and-forward method
• Fragment-free method
• Cut-through method

Q3 – What is routing and switching?

Switching is the process of transmitting packets from one host to another inside a Local Area Network (LAN). Routing is a method of doing that between two or more local area networks.

Q4 – What is switching and types?

Switching in networking is the process of transferring data between devices or networks. There are two types of switching. These are:

1. Connectionless switching
2. Connection-oriented switching

Conclusion

Switching is a vital process in data communication that enables efficient and secure data transfer between devices or networks using switches. In this blog, we have explained what is switching in networking and its types, how it works, different types of switching techniques, and its advantages and disadvantages.

Switching is an important topic for CCNA Exam. So, if you are preparing for CCNA Certification, or taking CCNA Training, you should learn Switching in Depth.