Switching

Switching is the process of transferring data packets from one device to another in a network or from one network to another network using a specific device that is called SWITCH.

User experience switching all the time for example accessing the internet from your computer device where a user requests a webpage to open the request is proceed through the Switching of data packets only.

Network Switching 

The switch is a dedicated piece of computer hardware that facilities the process of switching i.e incoming data
packets and transferring them to their destination.

A switch works on the data link layer of the OSI Model 

                                    ""A switch primarily handles the incoming data packet from a source computer or network and decides the appropriate port through which the packet will reach their target computer or network""

Switch decides the port through which the packet shall pass with the help of its destination MAC(Media Access Control) address. A switch does this effectively by maintaining MAC tables(Switching Tables) also known as Forwarding Tables.

Switching Process:

There are 5 steps as follows 

• Frame Reception: The switch receives a data frame or packet from a computer connected to its ports.
• MAC Address Extraction: Switch reads the headers of the data frame & collects the destination MAC address from it 
• MAC Address Table lookup: once the switch has retrieved the MAC address it performs a lookup of its switching tables to find a port that leads to the MAC address of the data frame 
• Forwarding Decision & Switching Table Update: If the switch matches the destination MAC addresses of the frame to the MAC address in its switching table it forwards the data frame to the respective port. If the destination MAC does not exist switch follows a flooding process in which it sends the data frame to all its ports except the one it came from and records all the MAC addresses to which the frame was delivered by this switch finds the new MAC addresses & updates its forwarding table.
• Frame Transition: Once the destination port is found the switch sends the data frame to that port and forwarding/forwards it to its target computer/Network.

Type of Switching 

-Message Switching 

-Circuit Switching 

-Packet Switching 

    +Datagram Packet Switching 

    +Virtual Circuit Packet Switching 

Message Switching 

Older switching technique that has become obsolete In it the entire data block/message is forwarded across the entire network thus making it highly ineffective.

Circuit Switching 

In this type of switching a connection is established between the source and destination connection receives the complete bandwidth.

Packet Switching 

Requires the data to be broken down into smaller components data frame or packet. Data frames are then transferred to their destination according to the available resources in the network at a particular time.

        This type is used in computer & internet 

            + Datagram Packet Switching 

                                                    Each data frame is taken as an individual entity and thus they are processed separately there is no connection established before data transmission occurs. Although this approach provides flexibility in data transfer it may cause a loss of data frames or late delivery of the data frames.

            + Virtual Circuit Packet Switching 

                                                     A logical connection between source & destination is made before transmitting data this logical connection is called a circuit.