Packet switching refers to the method of dividing data into packets to make its transmission over a network faster and more efficient. The concept was first developed in the early 1960s, but the term wasn’t coined until a few years later. Since then, packet switching has become a fundamental concept behind how the Internet works.
The concept is similar to sending a giant puzzle to a friend via the postal service. Since the puzzle is too large and may cause congestion, the post office staff decides to mail its pieces separately so transport would become easier and faster. In the same way, anything sent over a network is divided into data packets to manage the traffic better.
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How Does Packet Switching Work?
When you send a 5MB file over the Internet, it would be broken into data packets. When all packets reach the recipient, they are assembled into the original file. What happens in-between the sending and receiving phase depends on the type of packet switching discussed in the succeeding sections.
Types of Packet Switching
Connectionless Packet Switching
In connectionless packet or datagram switching, each packet has a header that contains the following important information:
- Origin IP address
- Destination IP address
- Number of packets in the file
- Sequence number of the specific packet
These details ensure that the data packets would reach the destination completely. On their way to the receiving device, the packets are transmitted over the most efficient route for each of them. That means that not all packets use the same path and they may not arrive in the correct order.
Connection-Oriented Packet Switching
In connection-oriented packet switching, the header contains a connection identifier rather than the address. Packets are less bulky compared to connectionless packet switching. However, the type of communication and route has to be established first before the packets are transmitted. Connection-oriented packet switching is also known as “virtual circuit switching” and it mostly uses the Internet Protocol and Transmission Control Protocol (TCP/IP) as the primary communication protocol.
Packet versus Circuit Switching
An alternative to packet switching is circuit switching, a communication method that requires a dedicated channel. The best example of circuit switching is the telephone. When you call your mother over an analog telephone line, you use a dedicated circuit or channel, and no one else can use that channel.
The dial-up Internet connection is akin to circuit switching. When someone in your house uses the Internet, nobody can use the telephone. With packet switching, multiple devices can communicate simultaneously.
Here is a video detailing the difference between packet and circuit switching:
Benefits of Packet Switching
Packet switching has several advantages. Among them are efficiency, cost-effectiveness, and reliability.
The primary reason behind the wide acceptance and usage of packet switching is that it allows for the simultaneous use of the same network. It doesn’t need dedicated channels, so each data packet can be directed to the best route, making it efficient for Internet connections.
Since there is no need for separate networks and channels for different traffic types, packet switching allows us to save. Data can travel through the same network that video and voice traffic use.
Loss of data is often normal in network communications. However, packet switching minimizes the risk since the receiving device can request for the missing packet when it detects one after an examination. The originating device can then resend the lost packet.
While packet switching may not be a household name, it helps make the Internet work the way it does today. And now that you know what is packet switching, the next time you call a friend or send a file to your colleague, think of the data packets transmitted in the background. They make our lives relatively easier (at least compared to the telegram and dial-up days).