Switching | Computer Networks

Switching is the process of transferring data packets from one device to another within the same network or across networks using switches. It happens at the Data Link Layer (Layer 2) of the OSI Model, right after the Network Layer generates data packets.

• A switch is a device that connects multiple devices in a network.
• It ensures data from different devices does not interfere.
• Works like a traffic controller by sending data packets to the correct port.
• Sends data directly to connected devices (e.g., computer, phone).
• For other networks, it forwards data to a router for delivery.

Example: When you open a website, your request is broken into packets and forwarded through various switches before reaching the server.

Network Switching

Network Switching is a specific type of switching, used in computer networks. It is about transferring data packets from one device (node) to another across a network.

It involves the following steps:

• Frame Reception: Switch receives a frame from a device.
• MAC Address Extraction: Reads the destination MAC address from the frame.
• Lookup: Searches its switching table for the destination MAC address.
• Forwarding: If found, sends the frame to the correct port. If not found, uses flooding (sends to all ports except incoming one).
• Table Update: Learns new MAC addresses and updates the table for future forwarding.
• Frame Transition: Forwards the frame to the correct device/network.

Types of Switching

There are three types of switching methods:

• Message Switching
• Circuit Switching
• Packet Switching

1. Message Switching: This is an older switching technique that has become obsolete. In message switching technique, the entire data block/message is forwarded across the entire network thus, making it highly inefficient.
2. Circuit Switching: In this type of switching, a dedicated connection is established between sender and receiver before communication starts. This connection receives the complete bandwidth of the network until the data is transferred completely.
3. Packet Switching: In packet switching, data is divided into small packets that travel independently through the network using available paths. Each packet carries its destination address, so switches and routers know where to send it. At the destination, packets are reassembled into the original message. This is the method used in modern networks and the Internet because it is fast and efficient.

Comparison of Switching Types

Switching in Computer Network

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