Message-Switched Networks

In this tutorial, we will be covering the concept of Message-Switched Networks as well as Message Switching in Computer Networks.

The Message-Switching Technique was mainly developed to act as an alternative to circuit switching, this was before packet switching was introduced. Basically, the message is a smaller unit.

• In the Message-Switching technique, the communication between end users is done by sending and receiving the message, and this message includes the entire data to be shared.

• In Message-Switching there is no dedicated path between the sender and receiver like circuit switching.

• The sender and receiver are connected by way of several intermediate nodes which helps and ensures proper data transfer between them.

• Message-Switched data networks are also known as hop-by-hop systems.

Characteristics of Message Switching

Given below are two characteristics of Message switching:

• Store and Forward
  As we have already told you that the sender and the receiver are not directly connected to each other. Thus intermediate nodes between sender and receiver are, mainly responsible for transferring the message to the next node in the path. Thus in order to transfer the message, intermediate nodes must have the storage capacity because any message will only be delivered if the next node and the link between them are available to connect otherwise this message will be stored indefinitely. A store-and-forward switch thus forwards a message only if sufficient resources are available and the next node is ready to accept the data. The process continues till the data is delivered to the destination computer. Hence, it is called store-&-forward property. The store-and-forward property was earlier used in telegraph message switching centers.
• Message delivery: In the Message Switching the entire information is compiled into a single message and then that message is transmitted from source to destination. To successfully reach its destination each message must contain the routing information in its header section.

Figure: Message Switching and Message-switched Network

Advantages of Message Switching

Given below are some advantages of using Message switching:

• In this Switching, data channels are shared among network devices.

• There is Management of traffic in an efficient way by assigning priorities to the messages.

• There is an improvement in efficiency as a single channel can now be used for transferring many messages.

• There is a reduction in network traffic congestion because in this technique we are using store and forward property and also any switching node can store the messages till the availability of the network.

• With the use of Message Switching, messages of unlimited size can be sent.

• It requires less bandwidth while broadcasting the messages; thus it consumes less bandwidth than circuit switching.

• In Message switching, if the next node or link is not available then the current node stores the message

Disadvantages of Message Switching

There are some drawbacks of using Message Switching and these are as follows:

• For the whole network, message switching requires a large capacity.

• This technique cannot be used for real-time applications because the storing of messages causes delay.

• The message-switched networks are very slow in nature because the processing takes place in each and every node and thus it may result in poor performance.