Internet Calling Followup

With regard to last week’s when VoIP is not VoIP missive, based on some feedback I’ve received, there are apparently a few things I need to clear up.

Some people got the impression that I was suggesting we should forsake the traditional PSTN network entirely:

Having the PSTN in the loop for calls that are terminated on the PSTN is perfectly legitimate and of course required to complete the calls. Requiring the PSTN in the loop for all calls is what makes no sense. The PSTN is not going away any time soon and I appreciate that as much as anyone.

Also, some people suggested that it will be fine because the Telco-based VOIP carriers will start to use the Internet to route calls when it makes sense for them:

That’s great, but it misses the point. When I sign up with a VoIP provider, I want to know I can be reached from the Internet directly, if I so choose. I want a SIP address and I want people that have the ability to call a SIP address to be able to call me at that address. I also want to be able to call other people with SIP addresses, even if that person doesn’t have a Telco-connected VoIP provider.

People will say this will happen when the carrriers all support ENUM. That’s only partially true. First, it will be a long time before carriers support ENUM, if ever. Which of the carriers give me an ENUM entry with my VoIP service today and allow calls from an ENUM capable SIP proxy? The answer is none and there isn’t even a mechanism for adding +1 (USA) numbers to ENUM (the details have not been worked out). Finally, if the carrier supports ENUM, then it means they must support accepting inbound calls via SIP routing so ENUM is somewhat irrelevant to (or orthogonal to) the issue.

Further, I don’t want the decision left up to the carrier. If I know the address of a user on the Internet, I want to be able to call them at that address. Why should I have to wait for the carrier (and the world at large) to deploy ENUM, when I can place that call today via SIP address using VoIP providers that support that ability. That said, having the carriers support ENUM is a very positive step and I hope they do so. That would put them that much closer to an open Internet service/application however, so I doubt we’ll be seeing that anytime soon.

That’s ultimately my main point I guess. There is the open standards based global SIP network, where like DNS or e-mail, everybody speaks the same protocols and can talk to each other, regardless of hardware or service provider. Then there is the PSTN; then there are hybrids and closed/proprietary alternatives (like Skype). Services that do not support the global SIP-based VoIP network aren’t participating in the Internet. They are using the Internet as a pipe for their closed systems and getting in the way of progress toward making VoIP just one more interoperable application on the Internet. Whether a VoIP provider is using SIP ‘behind the curtains’ is irrelevent if it does not connect to the global SIP network.

I agree with James Seng when he points out that ultimately there will be a spectrum of VoIP users and service providers, as there are such for e-mail:

I think e-mail is an interesting thing to model the future of VoIP on, but we must be careful not to take the analogy too far. E-mail was a new application, whereas voice is an application with a well-establish infrastructure. I think there will be room for VoIP service providers in the future, as James points out, but it will not be the only option, as many assume. Like e-mail, people will use a service provider when it adds value for them, and not otherwise. Also, not all service providers will be telco carriers.