How may I teach that SOAP is not a reliable transport?

Question

I need to teach that a HTTP SOAP call may be received but the caller may not get the response due to a network failure (among other problems). (This problem made WS-ReliableMessaging be developed)

How would you guys show this problem to a web service developer so they can develop taking into account that duplicate messages may be received?

The problem is that they do not understand that a HTTP call may be received perfectly by the server and acted on the server, but the response to the caller may be lost.

Answer 1

Hi Eduardo

What about a use case diagram or a timeline demonstrating the failure event during transmission?

Answer 2

I've seen this type of thing described through a UML Sequence Diagram. I thought it worked well and of course Sequence Diagrams will be familiar to most developers.

You might get some good ideas here: http://www.eventhelix.com/Realtimemantra/Networking/#HTTP_Sequence_Diagrams

Cheers,

Answer 3

Why not show a diagram of the messages going back and forth between client and server SOAP runtime over time? This diagram can show messages being lost at some point or duplicates arriving or messages arriving out of order.

It's quite simple. You have two vertical lines representing client and server parallel to each other. Then you have labeled lines (diagonal) between the two to indicate messages. A message lost in transport just as an X in the diagnoal line before it touches client or server. Hope this helps.