The video is long but frankly, David Welch is articulate and explains things in a way that most of you should be able to get the big picture view/forecast he is driving at for INFN.  The part where he goes into what 5G means for INFN's products (and everyone elses for that matter) drives the "secular growth" point.

Which, BTW, I should use that as a segway for repeating my view on the NOK investment:

NOK is an investment in a turn around play.  IMO, this alone should grow its share price into the $10 area.  Then the second phase is growth, read 5G, this is when NOK goes well into the teens.