Once the industry migrated to IP (Internet Protocol) telephony, we were told, buyers would be living in a new world -- one where they could mix and match phones and other system.  Prices would fall; life would be good.Well, things haven't turned out exactly as promised. Yes, virtually every vendor bows to the great unifier SIP (Session Initiation Protocol), but adherence to SIP is often honored more in the breach. Indeed, there are times when it's not honored at all. Apple's iPhone, for example, announced with unbelievable fanfare at last month's CES, is not SIP compliant.

 

'Disappointing but Not Surprising'

 

To be sure, SIP calls can and do go between phones and terminals from multiple vendors, but with so many vendor-specific extensions, the promise of feature transparency between multivendor systems remains largely unfulfilled. This is disappointing, but not surprising, for reasons that have less to do with technology than business models -- both the vendors' and the buyers'.

 

Everyone has a stake in being able to connect devices, no matter from which vendor; in all but a few narrow exceptions -- the more connections a network can support, the more valuable the network is to its owner and customers. So, since the carriers have designated SIP as their default signaling protocol, the manufacturers of communications have to support it.

 

At least to talk to the carriers' network; what goes on behind the demarc (demarcation point), however, is quite another matter. So, here is where both vendors and customers have common interests. The vendors want to deliver as much functionality as possible for all the obvious competitive reasons. As a result, they offer SIP and other "open" standards as part of the basic package, but reserve the real goodies for their proprietary protocols and software.