We all live in the world of high technologies. Today we have a lot of different things that make our life more comfortable, for example communication technologies in general and VoIP in particular. VoIP (Voice over Internet Protocol) may seem to be difficult but it makes our life easier. VoIP allows to conduct telephone intercourse through computer networks with the use of an internet protocol. Now VoIP or Broadband phone service, as it’s often called, is going to change the telephony world. Traditional phone lines are slowly being ousted from the communications market. The process of VoIP evolution accelerates. Over the last fourteen years, VoIP has made tremendous progress and today we are going to tell you about how it started and how it developed.
So, in the middle of 90s an Israel based company Vocaltec introduced the first VoIP software, called "Internet Phone" that was designed to run on a home PC. This application utilized microphones, speakers and sound cards and used the H.323 protocol (while nowadays SIP is more widespread, than H.323). "Internet Phone" had a great success. It can be compared to the today's Skype. But there was one serious drawback. These early attempts of the first IP phone resulted in reduced sound quality and poor connection although it did show the technology was helpful and promising.
The first VoIP application was developed by Alon Cohen, Lior Haramati, Opher Kahane, Ofer Shem-Tov, Late Elad Sion, Dror Tirosh and Rami Amit. Actually they were pioneers of VoIP.
The Vocaltec software downloads were not in millions as in case with extremely popular VoIP applications nowadays. But at that time there were not so many Internet users. The program itself cost approximately $60 and downloads were in tens of thousands. Internet Phone application was actually one of the first e-commerce software products (a software that was sold over the Internet).
The early attempts in the history of VoIP entailed both callers to have a computer, the same software along with the necessary hardware. The purpose of the software was to compress the voice signal, convert it to voice data packets and lastly send it out over the internet.
The VocalTec’s pioneering product was associated with significant hype which in effect helped to promote the whole VoIP industry. The hype element came from the fact that the international calls in 1995 cost very much. With the Internet Phone, people were able to call abroad for no charge at all. Among the early users of this software were journalists who generated a huge media attention around VoIP and VocalTec.
But still PSTN was ubiquitous. IP had to interwork with PSTN to make VoIP more widespread. The hardware and software developed in order to overcome this problem was the next step ahead. In 1996 VoIP companies (Audiocodes, Cisco, Net2phone, Nuera, NMS) were looking for a way to connect IP with PSTN. PC-to-phone application was introduced in August 1996 by Net2phone. Developers cooperated with hardware companies to achieve IP-PSTN interworking. Vocaltec collaborated with Dialogic (later bought by Intel), Net2phone worked with NMS Communications, and iBasis teamed with Cisco. The result was a PSTN breakout gateway or a media gateway. Soon phone-to-phone VoIP gateway was ready, and the user did not need Internet or computer in order to use VoIP.
Media gateway was the first commercial VoIP product. The first media gateways were made by Vocaltec, Nuera, Vienna Systems (bought by Nokia), Cisco, Clarent, and Ascend (bought by Lucent) in 1996-1997. Media gateways used protocol H.323 and SS7. The gatekeeper element (H.323 term) which is essentially the call controller was integrated with the first media gateways. The gateway and gatekeeper in VoIP split up in 1997/98. However integrated systems are used nowadays. So not all VoIP systems follow distributed architecture paradigm.
In 1998 MGCP protocol was standardized. Level 3 team developed the IPDC part while Telcordia contributed the SGCP part. Together these parts made up MGCP, which was endorsed by IETF and today forms an important component of overall SIP stack.
Moreover Level 3 worked at dialup modem traffic handling and developed its Softswitch project. The company considered voice as a potential target market. Voice continued to be the main motivation in late nineties. In 2000- 2002, dialup modem traffic increased significantly on Level 3 platform. Level 3 has contributed so much to VoIP technology.
Once VoIP succeeded in international long distance networks (ILD), service providers started pushing packetization from ILD POPs towards the edge. The next stage was the deployment of VoIP in national long distance network (NLD). And Level 3 played a main role in transitioning VoIP from international long distance wholesale to national long distance wholesale.
By 1998 VoIP traffic represented about 1% of all voice traffic in the United States. Different devices were created to enable phone-to-phone and PC-to-phone communication. By 2000 VoIP traffic achieved approximately 3% of all voice traffic. This result was related with the production of new equipment that could switch and route the VoIP traffic. The equipment was introduced by networking manufacturers such as Cisco and Lucent. It caused a great success in the United States and as the result other countries, including European, also did not remain aside.
The further development of VoIP shows that H.323 is not scalable for large scale systems. A new Internet style protocol called SIP (Session Invitation Protocol) was adopted by vendors in 1999/2000.
The SIP standard is defined in RFC 3261 by the Internet Engineering Task Force (IETF). The IETF is a large open international community of network designers, operators, vendors, and researchers who are all concerned with the evolution of the Internet architecture and the smooth operation of the Internet.
The draft of SIP was developed by M.Handley, E.Schooler and H.Schulzrinne in February, 1996. SIP was originally intended to create a mechanism for inviting people to large-scale multipoint conferences on the Internet Multicast Backbone (Mbone). At that time, IP telephony didn't really exist. In 1996 the protocol still was yet to take the shape of SIP as we know it now.
Even in 2000 when SIP was gaining its popularity among the VoIP community SIP-based network vision did not immediately succeed and was not adopted by all the developers. First of all, this approach reduces carriers to mere suppliers of commodity transport. There is no role for them in creating value and capturing margin.
It is improbably that carriers would deploy an architecture that is going to lessen their mportance and decrease their income. Some developers, for instance Dynamicsoft, realized the problem a long time and added elements to provide intelligent SIP-based core routing. Hence SIP kept evolving towards greater network intelligence.
The history of VoIP evolved over the next several years and by 2000 there were several companies offering PC-to-phone service and phone-to-phone service. For a phone-to-phone connection it usually was necessary to use a PC to originate the call, even if the actual communication is from phone to phone. This service was offered to users only in North America. To subsidize the cost of early VoIP, service providers used advertising sponsorship rather than charging the user. An advertisement would often play at the beginning and end of the call.
VoIP industry had grown astonishingly since 1995 and was going to change the telecom when the market downturn hit in 2000. Reasons for this slowing down were mainly economical ones. The free PC-to-phone service providers (Dialpad, PhoneFree etc.) could no longer pay the PSTN breakout charges due to reduced advertising revenues from which they generated their income. It was a difficult time for the industry. Many service providers were in financial trouble and some of them became bankrupts.
But VoIP survived and was saved by deploying broadband network. Broadband access users had plenty of bandwidth to play with. And they often used PC-to-PC VoIP. By that time analog telephone adaptors (that were used during early PSTN dialup times) had been improved to comply with the broadband network and users did not need a computer to make VoIP calls over the broadband connections.
In 2003, the telecommunication industry woke up to a quiet revolution. It took place at the same time on three different continents. In America, Vonage was a success with its VoBB (Voice over Broadband) consumer numbers. In Europe Fastweb Italy became the world’s first triple play service provider, offering VoIP, IP PTV and Internet on one line. In Japan, Softbank started giving free Cisco ATA to clients to try VoIP. Softbank had millions of users and it was the first company that succeeded deploying VoBB.
In 2003 Skype appeared and later became the most influential consumer offering that the VoIP industry has ever produced. The success of Skype was connected with its simple peer-to-peer architecture that does not need central servers or central resources to scale. Moreover PC-to-PC calls are free. Skype got started six years ago, when consumers were changing their dialup connections to broadband. In that sense Skype’s launch timing was excellent. And that is the main reason for its flourish. Then there was obviously the snowball effect. Success breeds success. Everyone wanted to work with Skype. These factors combined made Skype a bigger hit than the previous softphone based VoIP offerings. Skype restored the original glory of VoIP i.e. a softphone led revolution.
A period after 2006 is often referred to as 2nd generation VoIP when SIP with its simplified architecture is becoming a standard for all the manufactures and service provider. SIP has widened the scope of VoIP from voice to include IM, video, wireless and carrier products.
SIP is going to overcome the limitation of proprietary hardware equipment. Earlier telecommunication equipment vendors have held their clients hostage to over-priced and restricted-functionality telephones and other equipment. SIP is the great equalizer, enabling different vendors' devices to interwork, allowing users to choose the best equipment in accordance with their needs and financial situation. Now manufacturers can compete on performance and price in an open environment based on SIP.
There are several merits of SIP that made it so popular:
SIP allows program developers to create applications that will comply with all phone systems, thus lowering the costs of software significantly.
Earlier VoIP standards were insecure. SIP provides a common security standard for carriers and vendors.
SIP may be used in IP phones, computers, mobile phones, IM clients, video devices and PDAs . By the way Microsoft is SIP-enabling it’s products so if you use Microsoft Windows your computer will be a SIP device, just like your phone. So, users will be able to go anywhere, but still communicate as if they were in their home or office. For example, SIP’s awareness of a user’s communication capabilities will help travelers who have to use different mobiles and protocols in different places of the world. Thanks to SIP a person who wants to call such a traveler need not know his availability or location. SIP by nature will know how a users can be reached, and facilitate the connection.
SIP has an inherent capability to support peer-to-peer systems. Peer-to-peer environments do not depend on communications servers, gateways, or other auxiliary devices. Peer-to-peer SIP networks are easy to set up and administer yet can include features such as automated attendant, voicemail, and multi-party conferencing.
SIP is a structured, text-based protocol that is modeled after HTTP (a HyperText Transport Protocol), on which the World Wide Web is based. SIP is acceptable for a larger developers community than CTI. Because SIP is based on HTTP, programmers and software engineers will have an easier time developing and integrating software into their communications environments. Moreover, SIP is easy to learn, troubleshoot, and support. From analyzing network packets to application code, SIP’s structured language stands out so that IT people can easily understand and interpret it.
With SIP a very promising segment of VoIP, a mobile VoIP is flourishing now allowing users to make inexpensive or completely free mobile calls. This exciting possibility attracted millions of users worldwide. Among the latest SIP-based mobile applications we should mention sipManiac that combines user-friendly interface and excellent functionality.
Over the last fourteen years, VoIP has made tremendous progress. Evolution of VoIP is phenomenal but the future of this technology is going to be even more amazing and promising. Today we can use products that our grandparents and even parents could never imagine. So, take your chance. Enjoy comfortable communication, enjoy VoIP!