Switching and its types in Computer Network

 What is Switching?

• Computer networking's most important resource is switching. You use the internet or another computer network beyond your immediate area every time you use a computer network, or your communications are sent through a maze of transmission media and connection equipment. 
• Switching in networking refers to the technique for exchanging data across different computer networks and network segments. 
• In other words, any form of signal or data element that is directed or switched toward a certain hardware address or hardware parts.

Types of Switching.

• There are basically three types of switching methods are available.

1. Circuit Switching.
2. Packet Switching.
3. Message Switching.

Circuit Switching

In circuit switching following steps are included..

• Circuit Creation:- A dedicated circuit is built from the source to the destination via a series of intermediary switching centers during this step. To request and acknowledge the creation of circuits, the sender and receiver send communication signals.

• Data Transmission:- Once the circuit has been established, data and voice are transferred from the source to the destination. The dedicated connection remains as long as the end parties communicate.

• Circuit Disconnection: When the data transfer is finished, the link is disconnected. Any of the users can initiate the disconnection. All intermediate links between the sender and the receiver are disconnected during disconnection.
• The real-time connection-oriented system is circuit-switching. During a communication session, a dedicated channel (or circuit) is set up for a single connection between the sender and receiver. 
• The regular voice call is an example of Circuit Switching in a telephone communication system. 
• For each telephone call, the telephone service provider maintains an unbroken link. 
• The three phases of circuit switching are circuit formation, data transfer, and circuit termination.

Circuit Switching

Advantages:-

• Because a continuous transmission path is built and maintained throughout the conversation, it is appropriate for extended continuous transmission.
• The dedicated communication line assures a constant data rate.
• Once the circuit is built, no intermediate delays are found. As a result, they are appropriate for both speech and data transmission in real time.

Disadvantages:-

• Circuit switching creates a dedicated link between the two end points. Even if the data load is relatively low, this dedicated link cannot be used for any other data transmission.
• Even when the data volume is minimal, the bandwidth requirement is considerable.
• The system's resources are underutilized. Once resources have been assigned to a connection, they can no longer be used for other connections.
• The amount of time it takes to establish a link could be considerable.

Packet Switching.

• Packet switching is a network switching technology that does not require any connections. 
• The message is then separated and bundled into a number of pieces called packets, each of which is routed separately from the source to the destination. There is no need to set up a specialized communication channel.
• The Internet is the most basic example of packet switching. Data can be broken into suitably-sized bits of varying length or blocks called packets, which can be transported independently by network devices based on the destination address included inside a specified "formatted" header within each packet in packet switching. 
• Sender and recipient can communicate without reserving a circuit in packet switching networks. In a packet switching network, there are multiple pathways between the sender and the recipient. To transfer packets between sender and destination, they do not require a call setup.

Packet Switching

Advantages

• The time it takes for packets to arrive is reduced because they are sent as soon as they become available.
• Because switching devices do not have to store the complete message before transferring it to the next node, they do not require a lot of storage.
• Even if certain sections of the network experience link loss, data delivery can continue. Other pathways can be used to route packets.
• It allows numerous users to use the same channel at the same time.
• It promotes greater bandwidth utilization by allowing many packets from different sources to be transmitted over the same channel.

Disadvantages

• They're not appropriate for applications that can't tolerate communication delays, such as high-quality voice calls.
• High installation expenses for packet switching.
• The delivery of these items necessitates the use of complicated methods.
• Packet failures, packet delivery delays, and packet loss can all be caused by network issues. This could result in the loss of crucial information if not handled properly.

Message Switching

• During the data transmission, message switching does not establish a dedicated channel (or circuit) between the sender and the recipient. 
• Each message is considered as a separate block in Message Switching.
• Message switching is a connection less network switching technique in which the full message is routed one hop at a time from the source to the destination.
•  It served as a forerunner to packet switching.
• Each message is then transmitted across the inter network from first network device to second network device, i.e. from sender to inter mediator device, under this style of networking.

Message Switching

• The intermediate device temporarily holds the message before transmitting it to the next node with its routing information after inspecting it for faults. 
• Message switching networks are known as store and forward networks in networking because of this.

Advantages

• Better bandwidth use is ensured.
• Because of the store and forward strategy, it decreases network congestion. 
• Until the network is available, any switching node can store the messages.
• Message broadcasting uses a lot less bandwidth than circuit switching.
• It is possible to send messages of any size.
• As opposed to packet switching, it does not have to cope with out-of-order packets or lost packets.

Disadvantages

• Each intermediate switching node needs a lot of storage to store a lot of messages of different sizes.
• Each switching node experiences a delay when using the store and forward method. As a result, it can't be used in real-time applications.