Difference Between Circuit Switching and Packet Switching

Difference Between Circuit Switching and Packet Switching

Team Careers360Updated on 02 Jul 2025, 05:05 PM IST

Here, in this article, we are going to discuss packet switching and circuit switching

Difference Between Circuit Switching and Packet Switching
Difference Between Circuit Switching and Packet Switching

What is Packet Switching?

We can define packet switching as a connectionless network. The messages in packet switching are divided and grouped together in the form of packets. After that, each packet is routed from the source to the destination in the form of individual packets. These packets carry the actual data by the payload. It is the responsibility of the destination to put these packets in the right order, when the packet arrives at the destination. This switching can be considered useful as an alternative to circuit switching. In the packet-switched network, data moves in discrete units having variable lengths. Now let us explore more about the advantages and disadvantages of packet switching.

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Advantages and Disadvantages of Packet Switching

Advantages

  1. We do not find any delay in the delivery of the packets because they are sent to the destination as soon as they are available.
  2. We do not find any requirement for massive storage space because the information is passed on to the destination as soon as they are received.
  3. Due to the failure in the links, the delivery of the data is not stopped as these packets can be routed from different paths too.
  4. The same channel can be used by multiple users while transferring their packets.
  5. We find the usage of bandwidth better in case of packet switching because multiple sources can transfer packets from the same source link.

Disadvantages

  1. Packet switching is very expensive to install.
  2. Even when complicated protocols are used, the delivery of these packets becomes easy.
  3. We cannot use high-quality voice calls in packet switching because there is a lot of delay in this type of communication.
  4. As a result of connectivity issues, loss of information and delay in the delivery of the information can take place.
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Commonly Asked Questions

Q: What is meant by "store-and-forward" in packet switching?
A:
"Store-and-forward" refers to the method used in packet switching where each intermediate node (router) receives a complete packet, briefly stores it, analyzes its header for routing information, and then forwards it to the next appropriate node. This process is repeated until the packet reaches its destination.
Q: What is the concept of "best effort delivery" in packet switching?
A:
"Best effort delivery" in packet switching means that the network attempts to deliver all packets but doesn't guarantee delivery or a specific quality of service. This approach allows for efficient use of network resources but may result in packet loss or out-of-order delivery.
Q: What is the role of routers in packet switching networks?
A:
Routers in packet switching networks play a crucial role in directing packets to their destinations. They examine the addressing information in each packet, determine the best path forward based on current network conditions, and forward the packets accordingly.
Q: What is the significance of packet headers in packet switching?
A:
Packet headers contain crucial information for routing and reassembly, including source and destination addresses, sequence numbers, and protocol information. This allows each packet to be treated independently and enables the network to make dynamic routing decisions.
Q: What is the concept of "multiplexing" and how does it differ in circuit and packet switching?
A:
Multiplexing is the process of combining multiple signals or data streams for transmission over a single medium. In circuit switching, time-division or frequency-division multiplexing is used to share a physical link. In packet switching, statistical multiplexing allows dynamic sharing of bandwidth based on actual traffic needs.

What is Circuit Switching?

We can define circuit switching as the method of switching used for establishment of a dedicated communication path between the sender and the receiver. The link established between the sender and the receiver is in the physical form. We find the analog telephone network as a well-known example of circuit switching. In this type of switching, bandwidth is fixed. Now let us explore more about the advantages and disadvantages of circuit switching.

Advantages and Disadvantages of Circuit Switching

Advantages

  1. We have fixed bandwidth.
  2. Since a dedicated communication channel is used, the quality of communication is comparatively increased.
  3. The rate of data transmission is fixed.
  4. There is no wastage of time in waiting.
  5. We prefer it for long and continuous communication.

Disadvantages

  1. Due to the use of dedicated channels, more bandwidth is required.
  2. The resources are not fully utilized.
  3. Since a dedicated channel has been used, the transmission of other data becomes impossible.
  4. It takes a long time for the establishment of the physical link by the two stations.
  5. Since every connection uses a dedicated path establishment, Circuit switching is expensive.
  6. Until and unless the user terminates the link, the link between the sender and the receiver will be maintained. If there is no transfer of data taking place, then this will also continue.

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Commonly Asked Questions

Q: What is the significance of connection setup in circuit switching?
A:
Connection setup in circuit switching is crucial as it establishes a dedicated path for communication. This process takes time but ensures a consistent quality of service once established. However, it can lead to inefficient use of network resources during periods of inactivity.
Q: What is packet loss, and why doesn't it occur in circuit switching?
A:
Packet loss occurs when data packets fail to reach their destination, usually due to network congestion or errors. It's a phenomenon specific to packet switching. In circuit switching, data loss is less likely because a dedicated, uninterrupted path is maintained throughout the communication.
Q: How does packet switching differ in terms of resource allocation compared to circuit switching?
A:
Packet switching allocates network resources dynamically based on demand, allowing multiple communications to share the same channels. In contrast, circuit switching allocates a fixed amount of resources for the entire duration of a connection, regardless of actual usage.
Q: How does latency differ between circuit switching and packet switching?
A:
Circuit switching typically has lower latency once the connection is established, as data travels along a dedicated path. Packet switching may have higher latency due to the store-and-forward mechanism and potential queuing delays at routers, but this can vary depending on network conditions.
Q: How does bandwidth utilization compare between circuit and packet switching?
A:
Packet switching generally offers better bandwidth utilization as it allows multiple users to share the same communication channels dynamically. Circuit switching, on the other hand, may result in underutilized bandwidth during periods of silence or low activity in a dedicated connection.

Circuit Switching Vs Packet Switching

We can also define circuit switching as a method of switching that uses a dedicated connection between the sender and the receiver for the transfer of data. There are three phases of circuit switching mentioned below:-

  1. Circuit Establishment: Between the sender and the receiver, we establish a dedicated physical route. The path may have a number of intermediate switching centers.
  2. Transfer of Data: When the establishment or setup phase is done, the data is transferred through these dedicated paths.
  3. Circuit Disconnect: When the data transfer is done, we disconnect the circuit from either of the two ends. In this phase, all the intermediate links are disconnected.

We find the use of circuit switching in telephones.

On the contrary, in the packet switching method, the data is broken into “pieces” or “packets”. It is transmitted individually from the source to the destination. After the packets are received, they are reassembled at the destination. In this method we do not require any pre-establishment of the dedicated route. There are two types of packet switching as mentioned below:-

  1. Virtual Circuit Based Packet Switching: In this mode of packet switching, for each packet we establish the virtual circuits. Each packet is then transmitted through the predestined route. In this mode we find similar phases as in the circuit switching method.
  2. Datagram Based Packet Switching: In this mode of packet switching, every packet has two parts. They are known as a header and a payload. The header of a packet contains the required information i.e. source and destination addresses, port identity, etc. On the contrary the payload contains the original data. Without any predestined path, these packets are transmitted randomly. All the packets are arranged and assembled, based on the header information at the receiver end.

NCERT Physics Notes :

Now, let us understand the comparison between circuit switching and packet switching with the help of the following table.

S.No
Circuit Switching
Packet Switching



1.There are three phases:
  1. Circuit Establishment
  2. Transfer of Data
  3. Circuit Disconnect
Direct transfer of data takes place.
2.In this type of switching a dedicated connection is required.This type of switching is connectionless.
3.The routes of the circuit are fixed.The routes of the circuit are flexible.
4.The processing of the data takes place at the source end.The processing of the data takes place at both the nodes and the source end.
5.It is used for voice communication.It is used for data transmission.

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Commonly Asked Questions

Q: What is the fundamental difference between circuit switching and packet switching?
A:
Circuit switching establishes a dedicated physical path for the entire duration of communication, while packet switching breaks data into smaller packets that can take different routes to reach the destination. This key difference affects how data is transmitted and network resources are utilized.
Q: How does circuit switching work in a telephone network?
A:
In circuit switching, like in traditional telephone networks, a direct physical connection is established between the caller and receiver for the entire duration of the call. This connection remains exclusive to that conversation, even during periods of silence.
Q: What are the main advantages of packet switching over circuit switching?
A:
Packet switching offers better network efficiency, as it allows multiple users to share the same communication channels. It also provides more flexibility in routing, improved fault tolerance, and can handle different types of data more effectively than circuit switching.
Q: Why is packet switching more suitable for internet communications?
A:
Packet switching is ideal for internet communications because it can handle bursty data traffic efficiently, allows for prioritization of packets, and can route around network congestion or failures. It's also more scalable and cost-effective for large-scale networks.
Q: How does packet switching handle data transmission?
A:
In packet switching, data is divided into smaller units called packets. Each packet contains addressing information and is sent independently through the network. Packets may take different routes and arrive out of order, but are reassembled at the destination.

Frequently Asked Questions (FAQs)

Q: What is the concept of "packet interleaving" in packet switching, and how does it improve network performance?
A:
Packet interleaving in packet switching involves mixing packets from different data streams or connections. This technique can help reduce the impact of burst errors and improve overall network performance by distributing the effects of network issues across multiple connections rather than affecting a single stream entirely.
Q: How does packet switching handle asymmetric data flows compared to circuit switching?
A:
Packet switching can efficiently handle asymmetric data flows (where upload and download speeds differ) by allocating bandwidth dynamically based on actual traffic needs. Circuit switching, with its fixed bandwidth allocation, is less flexible in accommodating such asymmetry.
Q: What is the role of buffer management in packet switching networks?
A:
Buffer management in packet switching involves controlling how packets are queued and processed at network nodes. Effective buffer management is crucial for minimizing packet loss, reducing latency, and ensuring fair resource allocation among different traffic flows.
Q: How does packet switching support network virtualization compared to circuit switching?
A:
Packet switching readily supports network virtualization, allowing multiple logical networks to operate on the same physical infrastructure. This is more challenging in circuit-switched networks due to their rigid, connection-oriented nature.
Q: What is the concept of "packet prioritization" in packet switching, and why isn't it applicable to circuit switching?
A:
Packet prioritization in packet switching allows certain types of traffic (e.g., real-time voice or video) to be given precedence over less time-sensitive data. This concept doesn't apply to circuit switching because all connections receive a fixed, dedicated amount of bandwidth regardless of the traffic type.
Q: What is the significance of routing tables in packet switching networks?
A:
Routing tables in packet switching networks contain information about network topology and are used by routers to determine the best path for forwarding packets. They are constantly updated to reflect network changes, allowing for dynamic and efficient routing decisions.
Q: How does packet switching support network redundancy compared to circuit switching?
A:
Packet switching inherently supports network redundancy as packets can be rerouted through alternative paths if a link fails. Circuit switching requires dedicated backup paths to be established in advance, which can be less flexible and more resource-intensive.
Q: What is the concept of "traffic shaping" in packet switching, and why isn't it necessary in circuit switching?
A:
Traffic shaping in packet switching involves controlling the rate of data transmission to ensure network efficiency and fairness. It's not necessary in circuit switching because each connection has a fixed, dedicated bandwidth allocation throughout its duration.
Q: How does packet switching handle network congestion control?
A:
Packet switching employs various congestion control mechanisms, such as TCP's slow start and congestion avoidance algorithms. These adjust the rate of packet transmission based on network conditions, helping to prevent or mitigate congestion.
Q: What is the difference in billing models between circuit switching and packet switching services?
A:
Circuit switching typically bills based on connection time, regardless of actual data transferred. Packet switching often uses usage-based billing, charging for the amount of data transmitted, which can be more cost-effective for bursty or intermittent traffic.