It should be an open and shut case, but it's not. And I make no apologies for the pun.
Defining "open" is much harder than it sounds when it comes to telecom equipment and networks. But I thought it was worth a try, so I put some questions to top service providers and then compiled the six answers I received. (See 6 Degrees of Separation: SPs Define 'Open'.)
Notice I didn't even try to put this question to makers of hardware and software, as I was quite sure their answers would be heavily influenced by product strategies. Even so, the perspectives from the service providers weren't in lockstep. Some stuck to the basics, while others got very specific, but all saw the value of openness both to themselves and to their customers.
And that's really the point here: Open as a concept can mean different things to different people and probably always will. But when it comes to applying "openness" to how telecom companies put together their networks, and how enterprises and even consumers connect to those networks, being on the same page is critical.
And this is something on which all six service providers agree: Misuse of the word and concept of "open" by vendors who add that description to their really quite closed technology systems is rampant, detectable, and pointless.
Or to paraphrase US Supreme Court Justice Potter Stewart, in his now-famous ruling on obscenity -- service providers may not always be able to define openness, but they know it when they see it.
— Carol Wilson, Editor-at-Large, Light Reading