With .NET Interoperability around, it’s very likely you’ll be synchronously calling external web services from C/AL, to exchange data. I won’t go into discussing whether or not this kind of architecture is good (my own position is that it isn’t), you may end up having situations where your C/AL code simply makes a synchronous call to external systems, such as web services.
Any external call is an expected point of failure. An important question you must always have in mind when calling external functions is transaction integrity. When writing code that targets only NAV, the structure of code is largely irrelevant, as long as you are not using COMMITs (which is another thing you should avoid at all costs). However, as soon as you introduce external calls, the structure becomes critically relevant. Critically relevant.
I’ve talked about this during my 2012 NAV TechDays session, and I promised I’d blog about it – so, here it goes.