History of Telco Network Evolution: The Three Key Phases

This article was published in Telecoms.Com on April 24, 2023. You can read the original article here.  

Telecoms.com periodically invites expert third parties to share their views on the industry’s most pressing issues. In this piece Founder and CTO of RtBrick, Hannes Gredler, offers some context for the current phase of telecoms network technology.

All technology is constantly evolving. The telecoms industry is no exception and has transformed massively since its inception. To those born during the last couple of decades, the early telecoms networks would have been unrecognisable. It’s hard to believe now, that in some areas if one phone rang in your neighbourhood, anyone on the same party line would have access to the conversation. Now, we have numerous ways of making a high quality, encrypted call from just about anywhere at a much lower cost – for both carriers and consumers.

Indeed, the cloud-native telecoms market is expected to be worth $115.6B by 2030. But how did we get here? From Bell’s patent of the telephone in 1876 to current day internet networks, this article explores the evolution of the telecoms network, broken down into three phases.

The first phase: telephony

In Greek, ‘tele’ translates to ‘far off’ and ‘phone’ to ‘speak’, hence the telephone is a device which connects audio signals over long distances. Bell’s patent of the telephone, granted in 1876, superseded the telegraph, an electrical text messaging system. Soon after, this invention allowed people to communicate from afar using manual switchboard operators to interconnect calls across trunk lines (which enabled longer distance communications). The 70s saw the creation of the Network Voice Protocol (NVP), which was a forerunner of Voice over Internet Protocol (VoIP), but for many years the telephone network was dedicated to delivering voice calls.

Traditional telephony allowed for real-time communication over a shared public switched telephone network (PSTN). It did this by converting voice sound waves to electronic signalling, initially over analogue equipment and then later by digitizing it. Snippets of conversation would be transported across the line and then the electronic signals would be converted back into sound signals to the recipient. Initially the network would have been made up of copper lines, most of which have since been replaced by fibre-optic cabling in modern-day networks to improve connectivity and speed.

The second phase: data packet networks (VoIP)

Packet networks grew up in parallel to the PSTN and were built solely to transmit data and messages. They evolved through various protocols, such as X25 to Frame Relay and then finally IP (Internet Protocol), and delivered content that was not real-time, such as emails and computer file transfers.

Internet telephony, known as VoIP, describes the process of making calls via the internet. VoIP was developed around 1995 to originally serve as a way to save money on long-distance and international telephone charges. It was the start of the converged telco network, that is one network that can be used for voice and data.

VoIP was initially sold as an add-on feature, however, packet networks soon absorbed telephony once telcos realised its potential benefits, such as its speed, cost-saving abilities, and better quality of sound.

Initially, this shift towards data packet networks and VoIP led to the arrival of new equipment vendors alongside the traditional suppliers. In time, however, the total number of vendors began to dwindle due to the overheads of developing purpose-built silicon. In order to satisfy the performance needs of modern networks, developing this silicon carries a huge fixed cost, which many simply couldn’t afford and therefore were not able to keep up with the rate of change.

The need to support ever faster networks was exacerbated by the growth of a third type of traffic – video. Like early voice and data networks, video had always had its own dedicated distribution networks, whether that was terrestrial wireless, satellite broadcast or cable TV. The advantages of streaming TV and video over a single Internet soon became clear, with on-demand services and multi-way video conferences driving up performance demands even further.

The third phase: cloud-native networks

Where does the telecoms industry stand now? The past few years have seen the birth of cloud-native networks, using off-the-shelf silicon from independent chip developers.

This type of network has been borne out of network disaggregation. Since the internet was invented, network software and hardware have been constructed as a monolithic system from a single vendor. Network disaggregation has decoupled software and hardware, offering far greater flexibility when building networks. A cloud-native network runs on independent software and hardware, as opposed to integrated systems.

Disaggregating networks has encouraged hardware innovation, including enabling a new generation of open switches, and a whole new approach to building networks, which has revolutionised the telco industry.

It has made building networks more flexible, cheaper and more power efficient. Most importantly, it has broken the tie-in between hardware and software in the same way that happened in the computing industry many years ago. The ability to use independent vendors has steered away from vendor lock-in and has meant consumers have more choice and more control over their networks.

What’s next?

The evolution of the telecoms network has had a knock-on effect on today’s economic developments. The move towards cloud-native networks has revolutionised the way we communicate and send information and has laid the groundwork for continued innovation in the telco industry. This is important, as the adoption of cloud-native networks is not yet widespread, but definitely where the industry is heading. From switchboard operators to cloud-native networks in the span of 150 years, we can only expect this exciting transformation to continue.


As company founder and CTO, Hannes leads the vision and direction of RtBrick. He has 20+ years of expertise in engineering and supporting roles working with Alcatel (now Nokia Networks) and Juniper Networks. Hannes is also a co-author and contributor to multiple Internet Engineering Task Force (IETF) drafts and is a regular speaker at industry events and conferences. He holds 20+ patents in the IP multi-protocol label switching (IP/MPLS) space.