Daily Payload

Skype Won the Protocol Wars

December 19, 2009

There has been a lot of debate over the years over which protocol won the protocol wars. Was it H.323? Was it SIP? No, the clear winner is Skype.

In case you missed it, Skype just passed the 20-million concurrent user mark on November 9, 2009. Skype allows users to place free calls anywhere in the world and, more often than not, the voice quality is the same or better than what is available on the PSTN.

Many have tried to compare H.323 and SIP, though it has always been hard to compare those protocols. H.323 was designed as an IP-based videoconferencing protocol. Contrary to opinion expressed by many, H.323 was not designed by people who only understood telephone networks. In fact, many involved in H.323 standardization had an Internet background. Even so, H.323 did borrow some signaling procedures from the PSTN, which only helped to further the misguided understanding. As the same time, though, the ISDN protocol elements H.323 borrowed actually helped H.323 not only be a better videoconferencing protocol, but an excellent VoIP protocol that integrated very well with the PSTN.

SIP, on the other hand, has struggled constantly over the years to find its place in the world. It has always been a weak telephony protocol that lacked the capabilities needed in many environments, yet it was often hailed as a great accomplishment nonetheless. Back in 1999, it was decided that SIP would be the protocol of choice for 3GPP, the organization that was defining what is now called the IP Multimedia System (IMS). IMS is very complex, requires a number of extensions to SIP to work, and only delivers comparable voice services available on a GSM phone today. Why the excitement? It allows equipment manufacturers to sell equipment, of course.

SIP has not failed, of course. It is used by other voice service providers like Vonage and tons of smaller companies around the world who have not managed to capture enough market share to really warrant mention. Perhaps one might claim success on the grounds that many dozens or hundreds of companies have tried to build a business on SIP, but they have not met with much success.

Skype, though, has captured the mind share and market share to be called the King of VoIP protocols. It is entirely proprietary, but built on technology that exploits the capabilities of the Internet. Skype allows one to use voice, video, instant messaging, and more. No matter how you look at it, Skype has been an amazing success.

Once again, though, we are now seeing a shift in the market. XMPP is becoming a major force in the market, as SIP never succeeded as an instant messaging and presence protocol. XMPP was designed from the ground-up to provide IM and presence capabilities and, interestingly, supports voice and video communications, too. Going forward, it is entirely conceivable that mobile devices and web portals will implement XMPP and users will utilize that protocol for all of their communication needs. In fact, Google has already taken steps in that direction.

The VoIP phenomenon has really been interesting to follow and to be involved in. It has significantly changed the way in which people communicate and the changes have been continuous over the past 14 years since the introduction of H.323 and SIP. What is interesting, though, is that the industry never truly settled on one protocol. Today, there are many deployments of H.323 and SIP. We are now seeing XMPP take hold and, with the advent of cloud computing and netbooks, we will likely see it take flight.

But can anything catch up to Skype? It seems to be able to outpace anything service providers can offer and there seems to be no limit to its potential.