12.6.1.1 explain the difference between packet switching and circuit switching
Packet switching vs Circuit switching
Circuit switching and packet switching are the two main models used for network connections.
Circuit switching
Circuit switching is a connection that requires a dedicated circuit to be established before data can be transmitted. (use protocol UDP)
Circuit switching is most commonly used to support telephone systems so that a conversation can be initiated whenever a user receives a call. Circuit switching provides the physical path between source and destination.
Circuit switching includes three phases:
Circuit establishment
Data transfer
Circuit disconnection
Advantages of using circuit switching
The sender and recipient addresses are only required at the stage of establishing a connection.
Guaranteed bandwidth for communicating subscribers.
Real-time traffic is transmitted without delay.
Ideal for voice communications (data packets are delivered in order).
Disadvantages of using circuit switching
The network may refuse to establish a connection.
Inappropriate use of bandwidth, which reduces overall network efficiency.
The dedicated circuit is not available for other services when the connection is in progress.
Packet switching
Packet switching is a data transmission model in which long messages are split into packets and sent to the recipient individually. (use protocol TCP)
These data packets are processed by a datagram. A datagram is the basic unit of transmission in a packet-switched network; it consists of a header, which contains the control information necessary for its transport over the network (IP address and MAC address of the sender and receiver), and data. The datagram sends each data packet individually and can travel any route. The problem with this method is that packets can arrive out of order or even get lost in transmission.
Most traffic over the Internet uses packet switching and the Internet is basically a connectionless network.
Packet switching step by step:
Data is split into packages
Each packet has a sender address, a recipient address, and a data block.
If the data requires multiple chunks, the number of each packet is indicated.
Packets sent to the network travel from router to router along different paths, so the delivery time for each packet may vary.
Once the packages arrive, they are re-ordered.
Message sent from recipient to sender indicating that the message has been received.
If there is no confirmation message, the sender retransmits the data.
Advantages of using packet switching
A dedicated channel is not required, packets can find the addresses in different ways.
Reliability, because helps to avoid packet loss.
In packet switching, data packets can be resent if they do not reach their destination.
Ensures that packets reach their destination.
Disadvantages of using packet switching
Not suitable for low latency applications.
If there is too much traffic, packets can be lost along the way.
Packet switching depends on a number of complex protocols that need to be managed.
