In the semiconductor world there are components makers, like Poet, that make individual parts used in a larger assembled, product, like a transciever. A Tier 1 company, like Cisco and Nokia, is a company that takes many individual components and assessmbles them into a finished product, like a transciever. And end user is the company, like Facebook and Google who buy and use the product, like a transceiver!

IMO, of course