Regaring Synchronous communication and ASynchronous Commu

Question

Hi,
Can any please describe me  for the above Synchronous communication and ASynchronous Commu. Please don't send any weblogs.. Or Documentations please  type the answers in simple language  just to understand excatly.
1.  when to use these.
2.  where to use..
3.  How its Usefull

Answer 1

Hi,
When you make a synchronous call i.e the message is sent, the receiving system is  active and can accept the call and further process it if necessary.
It is advantageous in a scenario which requires immediate return of data to the sender system.
One example would be where, you create a purchase order with account assignment in the sender system, and you want to perform a budget check in central accounting before you save the purchase order.
A disadvantage would be that both systems are required to be active.
In Asynchronous communication the receiving system does not necessarily have to be available at the time a function call is dispatched from the sender system. The receiving system can receive and process the call at a later time. If the receiving system is not available, the function call remains in the outbound queue of the sending system, from where the call is repeated at regular intervals until it can be processed by the receiving system.
An example would be, you are sending a purchase order to a vendor system. The sending system cannot influence the availability of the receiving system. If the receiving system is not available, the purchase order can be sent repeatedly until the vendor system is available again.
The obvious advantage of async communication is that the receiving system does not have to be available at the time the function call is made and the disadvantage is that processes that require an immediate response to the sender system cannot be executed using this method.
Hope this gives a clear idea of sync n async communication.
Regards,
Chandra