Computer network - three switching methods (circuit switching, packet switching, message switching and advantages and disadvantages)

Table of contents

Circuit Switching

Packet Switching

Message Switching

Compared

Advantages and Disadvantages of Circuit Switching

Advantages and Disadvantages of Message Exchange

Packet switching advantages and disadvantages 

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Circuit Switching

• The way a telephone exchange connects telephone lines is called circuit switching ;
• From the perspective of communication resource allocation, switching is to dynamically allocate transmission route resources in a certain way;
• Three steps of circuit switching:

1. Establish a connection (allocate communication resources)

2. Call (always occupying communication resources)

3. Release the connection (return communication resources)

When circuit switching is used to transmit computer data, the transmission efficiency of its lines is often very low.

Therefore, packet switching is often used in the Internet

Packet Switching

Suppose the user wants to send a message, usually we call the entire block of data representing the message a message;

Before sending a message, the longer message will be divided into smaller equal-length data segments. In front of each data segment, some headers consisting of necessary control information are added to form a A group can also be referred to as a "package". Correspondingly , the header can also be called a header .

• sender

Construct groups and send groups

• router

Caching groups, forwarding groups

• receiver

Receive packets and restore messages

Message Switching

It is one of the three methods of data exchange. The message is sent entirely, one hop at a time. Message switching is the predecessor of packet switching and was proposed by Leonard Kleinraucker in 1961.

Messages are exchanged using the "store-and-forward" method, which eliminates the need to establish lines in advance and to dismantle them afterwards.

Message switching uses messages as the unit of data exchange . Messages carry information such as destination address and source address. The storage and forwarding transmission method is used at the switching node.

Message switching was mainly used in early telegraph communication networks. It is rarely used now and is usually replaced by more advanced packet switching methods. Therefore, message switching will not be introduced in detail.

Compared

Advantages and Disadvantages of Circuit Switching

advantage:

1. Small communication delay
2. ordered transfer
3. no conflict
4. Wide range of applications
5. Strong real-time performance
6. Simple control

shortcoming:

1. Long time to establish connection
2. The line is exclusive and the usage efficiency is low.
3. Poor flexibility
4. Difficult to standardize

Advantages and Disadvantages of Message Exchange

advantage:

1. No connection required
2. Dynamically assign lines
3. Improve line reliability
4. Improve line utilization
5. Provide multi-target services

 shortcoming:

1. Caused forwarding delay
2. Requires larger storage cache space
3. Additional amount of information needs to be transmitted

Packet switching advantages and disadvantages 

advantage:

1. No connection required
2. High line utilization
3. Storage management simplified
4. Accelerate transfer
5. Reduce the probability of errors and the amount of retransmitted data

shortcoming:

1.  Caused forwarding delay
2. Additional amount of information needs to be transmitted
3. For datagram services, there are problems with out-of-order, lost or repeated packets; for virtual circuit services, there are three processes: call establishment, data transmission and virtual circuit release.