A Short History of the SIP Trunk – How did we get Here?

SIP trunking is a valuable technology and service that allows organizations to make calls over the Internet. The ability to route voice calls over the Internet gives enterprises many advantages like faster speeds, the ability to move different types of media over the same network, lower prices and so on. Today a large number of companies are opting for SIP trunking over hosted VoIP and the industry itself is rapidly evolving to meet the needs of customers.

The Earliest Phone Networks

Many things needed to fall in place before SIP trunking would become a viable tool for businesses. At the very beginning, we had basic analog landlines that were universally used around the world. Slowly fiberoptics started replacing the traditional copper cables which allowed phone companies to offer higher speeds for enterprises. The fiber-optic network represents the basic infrastructure and foundation that were required for the development of the Internet as we know it.

The Development of VoIP

A research paper called The Mathematical Theory of Communication by Claude E. Shannon laid the foundation for all Internet protocols as far back as 1948. It contained the initial theory and background for the process of converting digital data to analog and vice versa. Many years of work and research later, the VoIP protocol was developed in the 1970s. The earliest VoIP call was made in the same decade, thus kickstarting the digital voice revolution in the telephone industry.

The SIP Protocol

During the early phases of VoIP development, there were a number of protocols which could be used for making calls. A few researchers first designed the SIP protocol in 1996 specifically for allowing voice connections over the Internet. Later on, SIP was standardized. Since then, the SIP protocol has become the preferred standard for implementing most VoIP deployments. As you can see, SIP trunking would not exist without the creation and standardization of the underlying protocols.

The Development of VoIP Software for Individuals

During the 90s, VoIP was largely a toy that was mainly used by researchers and those with knowledge of the technology. Developers started making software that allowed the jewels to call one another over the Internet without having to pay their phone company. Over the next decade, many companies launched their own VoIP applications. VoIP quickly became a service that consumers recognized. It became part of the mainstream and users didn’t have to know about the technology to use it.

However, enterprises and businesses still did not try out VoIP and there were many reasons for this. The biggest reasons of course, were reliability and audio quality. At this point, the PSTN had been in existence for more than 100 years and was extremely reliable. Businesses relied on voice communication to a large extent and they could not afford to take risks on new and unproven technology. You could never be sure with VoIP if the call will go through and even if it did, it was no guarantee that it will not get disconnected in the middle of a conversation.

Apart from this, voice quality was also not that good partly due to slow Internet speeds. Of course, the protocol itself was still new and therefore had some inefficiencies, deployment issues and lack of optimization. Enterprises did not see enough benefits in VoIP to convince them to switch over from the PSTN.

The High-Speed Internet Revolution

In the early part of the century, Internet service providers started using cable and DSL instead of the traditional analog PSTN lines. Cable and DSL networks could provide faster Internet speeds for consumers. Pretty soon they were the default options for getting Internet access. Naturally, users saw a dramatic increase in the quality and reliability of VoIP calls.

At the same time organizations also started demanding high-speed Internet connections for various processes. Email, document collaboration, research, application software and many other processes relied on connectivity. Businesses started setting up robust internal networks, through both wired and wireless equipment.

SIP Trunking As We Know It

SIP trunks became popular as companies started demanding more efficient ways of making phone calls. Moving voice calls over to the Internet allowed businesses to eliminate a separate network. Now they only needed to set up and maintain one network that was capable of transferring any type of media. The name SIP trunk is a misnomer and a relic of the PSTN era, where a trunk was a bundle of wires.

With SIP trunking, there are no physical wires that connect a business to the voice service provider. It is a digital connection that allows vendors to offer phone services that are more efficient and less expensive than analog calls. Without SIP trunking, many users would be restricted to making calls within their own VoIP network. SIP trunks allow organizations to make and receive calls from traditional landlines as well as mobile devices, desktop computers etc.

Today the SIP trunking industry is evolving at a fast pace and vendors are competing with one another to offer services that are as easy-to-use as hosted VoIP.