IBM trades on the NYSE, but it also trades on an ECN (like
archipelago) or an oversees market like the London Stock Exchange.

Questions:
#1 - Does an ECN have to report executed transactions back to NYSE? 
For example, if a buyer sends 10,000 shares of IBM into
an ECN and the trade gets executed at a certain price, because
IBM was originally listed on the NYSE, does that mean teh ECN now
must report back to the NYSE the price and number of executed shares?

#2 - Does the daily trading volume for the NYSE reflect what has been
traded on ECNs?

Thank you for your question.
 
I believe that to answer it well, your question will require more time
and effort than the average amount of time and effort associated with
this price. Here is a link to guidelines about pricing your question,
in the pricing guide: https://answers.google.com/answers/pricing.html

In your case, since you've asked two questions, you might want to
divide them into two different posts, to increase the chances of
receiving a satisfactory answer.