We live in an era where every process is quick and responsive. Packet switching is one such technology used nowadays on data networks like the internet, LAN, WAN. The development of Voice over Internet Protocol (VoIP), enabled packet switching to easily transmit data and voice traffic. This allowed businesses to experience huge benefits in terms of cost, efficiency, and scalability. This switching refers to routing and transmitting of data in an efficient manner through the channel/network with minimal latency. The channel is made available for other purposes upon the completion of the transmission.
What is Packet Switching?
Definition: Packet switching refers to a set of protocols that uses a connection-less network switching approach to transmit the packets. In this switching, the messages are broken and grouped into small units called packets. These packets are transmitted individually across a digital network to reach its destination. Packets need not follow the same route to reach their destination. As all the packets arrive at a destination in a different order, the original message is recompiled by the destination itself. The packet switching diagram is shown below.
In this switching, packets have two parts – a header and a payload. The information in the header allows networking hardware/intermediate node to make sure that the packets are directed towards its destination, while the definite data is carried by the payload. Each packet has a source and destination address to travel independently over a network with a variable bitrate. Packets are forwarded asynchronously by intermediate nodes because of congestion, queuing, and so on, and hence follows different routes. These packets arrive at the destination in a different order, and the destination ensures to reassemble the data of the same file. Delays in Packet Switching The four types of delays in this switching are: Transmission Delay It simply refers to the time taken to send out all the packets, or, time is taken to absorb all the data bits onto the communication medium. Transmissiondelay relies on the length of the packet and the network’s bandwidth. Transmission delay = data size/ bandwidth = (L/B) second Propagation Delay Propagation delay refers to the time taken by the bits to travel from source to destination over the link. Distance and propagation speed are the factors that impact propagation delay. Propagation delay = distance/transmission speed = d/s Queuing Delay Queuing delay occurs because of the nature of traffic in the network. Therefore, it refers to the time spent waiting in a queue until it gets executed and is defined as follows – Average queuing delay = (N-1) L/ (2*R) Where ‘N’ is the no. of packets ‘L’ is the size of the packet ‘R’ is the bandwidth Processing Delay It refers to the time taken to process a packet. Processing delay also refers to the time required to check for bit errors, determine output link, etc. Total time or End-to-end time = Transmission delay + Propagation delay + Queuing delay + Processing delay Does Internet use packet switching as default? What exactly is the Internet? Popular notions vary, and, for those without some understanding of how the technology works, the Internet is easily confused with the plethora of applications and services available through it. The Commission has defined the Internet as "a global, packet switched network that enables interconnection between networks using the Internet Protocol. While this is true, it is only part of the story. The IP is not used just for interconnecting existing provider networks-it extends all the way to the end users of these networks. Put differently, end-user devices utilize the Internet as a packet-switched network directly-unless blocked by a firewall or similar device, every Internet-connected computer can send messages to every other Internet-connected computer in the same native IP format. More technically, the Internet is the packet-switched network that receives IP formatted packets from connected users and delivers them, immediately and unmodified, to the destination specified by the user in the corresponding field of the IP packet header. The genius of the IP, and the reason for its success, is that it enforces standardization only at a single, abstract network layer. This allows considerable flexibility in the lower transport layers and provides a consistent and transparent interface to higher application layers. Thus, an IP network can be built using any physical layer technologyso so long as that technology can accurately deliver IP packets to the next switch in the network. The advantage of this approach is that it allows the creation of a large, interconnected network using existing networks as transport. This flexibility greatly reduced adoption costs, which was crucial to initial adoption.
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