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From Circuit-Switching to Packet-Switching

How Modern Data Transfers have shaped Digital Communication

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Term Paper


Business Administration>General




Term Paper: Packet Switching Packet switching is the most commonly used technology in today's public and private data networks, such as the Internet or the US Department of Defense network, called TCP/IP. It was invented in the early 1960s to help the US military protect their newly created communications network from the first strike by the atomic bomb. It is based on the old circuit switching method. The packet switching method breaks the sent data into blocks or "packets" to make it easier and faster to pass various digital networks using network devices. Each of these blocks has the source address, receiver address, total number of packets, and sequence number of each packet in their header so that the reassembly can work quickly. After the blocks pass through the selected network from the devices to their receiving devices, the data packets are reassembled to create the original data ready for use. These data packets can be transmitted through any path of the network, and each data packet of the data set may be transmitted through a different path, because these data packets are thoroughly structured, so they are not scrambled and recombined in the wrong order risks of. Sometimes data packets are still lost, but they are broken down into small parts, most of the time this will not affect the transmitted data. 2.2-Circuit-SwitchingCircuit-Switching is the foundation of today's voice telecommunications network, called the "Public Switched Telephone Network" (PSTN). It establishes a connection between participants during a call, and is based on the fact that voice communication usually lasts for a long time in one direction and is not strongly affected by noise, but relies heavily on its transmission Speed, so there may be no delay in communication. Circuit switching transmits data in near real-time because it uses all the bandwidth available through the central office of the global telephone network. Unlike packet switching, circuit switching transmits its data to the receiver through a predefined route, without header information, because the packets are then sent from the source to the receiver in the correct order. Thereby, the route is reserved for data, and the internal security is safe, but it is difficult for the line user to change the original transfer line, so as to make changes during the connection process. The cost of making a call is therefore the leased telephone line and the bandwidth during the call. Once the call is terminated by one of the two parties, the leased line is free to other users. 3- The impact of circuit and packet switching on digital communications and the impact of circuit switching as a global data transmission standard, especially the impact of packet switching on changes in digital communications cannot be overemphasized. Before it was invented by Paul Baran in the 1960s, digital communication was based entirely on end-to-end circuit switching between the source and receiver, so it was easily cut off and malfunctioned. The idea of ​​decomposing data into data packets transmitted through different networks to its receiver and reconstructed there is revolutionary. The problem before that is that the circuit switching system takes a long time, sometimes several minutes to establish a connection. Once established, no other party can connect to either of the two connected parties. This was okay for voice communication at the time, but it was unacceptable for computers because their communication time was less than a few seconds. It takes a few minutes to establish a connection and then no other communication is a problem. The idea of ​​packet switching is to use a decentralized network, and this is the answer. It creates the possibility of establishing and changing connections between multiple devices, and at the same time, due to its decentralized nature and the use of multiple network devices, the risk of data loss during transmission is very low. Since its invention, this method has been implemented in many networks and has been greatly improved. It is the basis of the current Internet and many private networks (such as the US Department of Defense or the Central Intelligence Agency). Although used by many large networks, there are still some that do not rely on this technology because the transmitted data passes through many different devices and is therefore vulnerable to attacks by skilled extractors in the network. This is why important agencies like the Department of Defense have their own networks and even use the networks within the networks to transmit data and communications quickly and securely. Circuit switching as a whole is not ideal for the international data transmission standard because it is limited in changes after the connection is established and the possibility of being cut off due to its centralized system. Voice communication between circuit switching is an ideal solution because it needs to be fast, which is edge circuit switching is better than packet switching, and is more tolerant of lost data, such as a part of a word or sentence. Although packet-switched packets can find the fastest path to the destination immediately, so it is faster than circuit data transmission, but reassembly requires more time, which is difficult for voice communication and is more susceptible to this type of delay Influence. Read Less