Question

Message passing is both time- and space-coupled – that is, messages are both directed towards a particular entity and require the receiver to be present at the time of the message send. . Does such a system exhibit the same level of indirection?

Answer 1

The examples of a few systems in which both the reciever and the sender are required to be present at the same time of the message send are Message passing, Video calling/conferencing, a phone call, etc;

In such systems only it is required for both the sender and the reciever to be present at the same particular time in order to make the message delivery possible.

If a message is space coupled and time coupled, it very well means that the communication directed towards a given reciever(s) must exist at that moment of time.

This type of communication is also called Direct Communication.

So, in order for the message passing to properly work both the systems must have the same level of indirection, otherwise being present at the same time and having the same space might not be possible, thus as a result Message passing cannot be performed.