General Network Error: Update
Well the title of this post should be really No Update ! Indeed I received a huge list of replies and comments about this 'random' error.
<rant>The conclusion at this time is that almost everybody can face at least one time th error, but nobody is able to provide a solution</rant>
The only thing working in my case is to add pooling=false in the connection string. In the next few weeks, I will receive a new range of high performances switch for my different servers, so I will post on the results.
I think it's possible the error is happening because of a low performance network. So doing the tests will surely tell me if the hardware is the culprit or no.
I know it's the right time where Microsoft blokes are active, so maybe they have some hints :-)
Check here some comments I received.