Why do data networks use packet switching

Packet switching

The transmission of small amounts of data across different networks is known as packet switching. These data packets are broken down into data blocks in order to transmit them faster and more efficiently over networks. This is cut into data packets in one device and sent from this device to the other in order to achieve a goal in which all data packets are collected and reassembled.[1] Simply put, it's a method of breaking data files down into smaller packets or pieces for better sending them over different networks.

Functionality

When users send a data file over a network, it is often not sent as a whole document, but rather as a small data packet. A person sending a 5mb file will have divided the file into 512-byte packets which are then sent over the network. Each packet contains a header that contains 2 network IP addresses:

  1. Originating IP Address - This is the IP address from which the data file is being sent. It is also referred to as the end of the data transmission.
  2. Destination IP Address - This is the IP address to which the data packet should be sent. In other words, it is the receiving end of the data transmission.

Apart from that, the header also contains a number indicating the number of packets that the actual entire data file contains. When packets are lost on the network, they bounce around. Bouncing refers to the transmission of a data packet from one router to another until it can reach the final destination IP address. When multiple lost data packets bounce around the networks, this cold leads to network congestion and can slow down the entire system. A hop count has been included in the header to solve this problem. This refers to the number of times a data packet can go from one router to another. A maximum number of hops is allocated per package. This number of hops decreases every time a packet goes through a router. If the maximum number of hops is reached before a packet reaches its destination, it will be dropped by this router. This is one of the causes of packet loss.[2]

Modes

The two main modes of packet switching are:

Connectionless packet switching

Each individual packet in this type of packet switching network contains complete routing information and is individually forwarded to its destination address within the network. There can be several types of transmission, depending on the different loads on the available nodes in the network. In this system, each of the packages follows instructions provided by the written information in the package header. This includes information that is necessary to facilitate the reassembly of the data packets to create the entire data file.[3]

  1. Destination address
  2. Source address
  3. Total number of pieces
  4. Sequence number (seq #) needed to facilitate reassembly.

Connection-oriented packet switching

This mode of packet switching is also known as virtual circuit switching. Individual data packets in this mode are sent through a sequence over a predefined and identified route. These packets are put together with the help of a unique sequence number and then transported one after the other through the network to its specific destination IP address. It is not necessary to include the address information in the packet for this mode.[4]

Effects

In the past, the circuit protocol was often used for ISDN connections for telephone networks.[5] The alternative is packet switching. Below are some of the advantages and disadvantages of packet switching over a circuit switch:

advantages

  • It is the more efficient use of the entire network bandwidth due to its flexibility in routing the smaller packets over common links.
  • These are often cheaper to build because less equipment is required.
  • It's more reliable. If a package does not arrive at its destination as expected and the receiving computer detects that a package is missing, it requests that it be sent again.
  • It provides automatic redirection in the event that a node fails its journey.
  • It has no connected wires and can easily bypass broken parts of the network.
  • As the number of customers increases, the network only needs to expand slowly compared to circuit switching.

disadvantage

  • There are large delays in receiving messages due to the time it takes to package and route the packets. For most applications, these delays are not long enough to be significant, but high performance applications such as real-time video often require additional Quality of Service (QoS) technology to achieve the required levels of performance.
  • Shared physical connections carry the risk of a possible breach of network security. Appropriate safeguards must be consistent with protocols and other related elements in packet-switched networks.
  • Not suitable for small data packages - if the data package itself is only 600 bytes, then two packages with 512 bytes must be used with the address information.
  • Unpredictable latency.

history

Packet switching, like the evolution of hypertext, is a concept that can be attributed to Paul Baran in the early 1960s and then, independently a few years later, to Donald Davies and Leonard Kleinrock. Davies and Kleinrock's research in the related field of digital messaging helped Baran build the ARPANET, or the first packet-switched network that was later known to be used by many as the Internet.

"This packet-switching concept was a radical paradigm shift from the prevailing model of communication networks with dedicated, analog circuits built primarily for audio communication, and established a new model of discontinuous, digital systems that break messages into individual packets that are transmitted independently and then on the other end can be merged back into the original message. "[6]

Packet switching is the breakthrough that has continued to evolve since its inception. Countless hours of research by brilliant minds are still working to improve this technology to make it available to all, as evidenced by past success. It will take many years and billions of money, but it will all be worth it.


  1. https://searchnetworking.techtarget.com/definition/packet-switched↩︎

  2. http://www.teach-ict.com/technology_explained/packet_switching/packet_switching.html↩︎

  3. https://www.techopedia.com/definition/5603/packet-switching↩︎

  4. http://www.informit.com/articles/article.aspx↩︎

  5. https://www.lifewire.com/packet-switching-on-computer-networks-817938↩︎

  6. https://www.livinginternet.com/i/iw_packet_inv.htm↩︎