Traditionally, Voice telephony has been based on PSTN riding on the TDM technology. With the growth of IP, Voice over IP (VoIP) is being widely adopted for personal as well as business use in many countries. This white paper discusses IP Voice at length and the choices it offers to businesses in India, in light of the technology landscape, regulatory framework and future potential.

After the discovery of the telephone in 1876, it took humankind almost a century to discover that Voice could also be transmitted as packets over data networks. Of course, the mother of all data networks—the Internet—made its first appearance only in the 1960’s as ARPANET. Commercial VoIP (Voice over IP) was born in 1995 when an Israel-based company launched an application that used H.323 protocol to transmit Voice. Post that development, Voice telephony witnessed rapid progress. It took just a year, for instance, for VoIP to break away from the shackles of the computer with the development of media gateways. By the end of 1996, the introduction of an Internet telephony service that allowed calls between normal telephones had been announced. In 1998, the Media Gateway Control Protocol (MGCP)—one of the earliest protocols defining the interaction between media gateways and media gateway controllers—was standardized.

The turn of the century witnessed two developments that helped the rapid growth of VoIP. One, a new Internet style protocol called SIP (Session Initiation Protocol) was adopted as an alternative to the H.323 standard. Two, the first IP-PBX was developed.

With the evolution of networking technologies, businesses started to install local area networks (LANs) to move data traffic between employees. As these campus LANs started to extend into Wide Area Networks (WANs), IP emerged a clear winner as the preferred LAN protocol. The growth of IP pointed towards the possibility of converging Voice and Data networks within the enterprise as a way to increase efficiency and save money. However, circuit-switched PBXs and ISDN PBXs were not well suited to run on IP data networks.

IP PBXs solved this problem.SIP paved the way for SIP Trunking—a service tool that gave businesses the ability to run Voice communications as voice packets in digital form entirely on the Internet or VPN. A SIP trunk could connect an enterprise to an IP Voice service provider through an IP PBX.

In Western markets where regulators allowed Internet-PSTN calling, businesses started migrating to VoIP from traditional copper-wire systems, primarily driven by call cost savings. With time, they discovered more benefits. Collaboration—for instance—becomes easier within a converged network, particularly if the enterprise has deployed an UC suite. IP Voice is being put to business use in a variety of ways in different countries, depending on available technologies, affordability and regulatory boundaries.

By bringing Voice, Data and Video into a single converged IP backbone, enterprises are redrawing the boundaries of possibilities, while making communications management simple and efficient.

The Backbone for Truly Collaborative Workspaces

The ‘workspace’ is gradually transitioning from a cluster of divided spaces into a flexible, fluid, collaborative environment. This is particularly true for large campuses that are being designed or constructed afresh. In the near future, the IP network in an enterprise is likely to assume the role akin to that of the human nervous system (if it hasn’t already)—a single network carrying Data, Voice and Video. Communications devices get plugged into this network as, when and where needed—almost like limbs, just more flexible and modular—enabling people & machines to exchange information and collaborate on demand seamlessly. Conferencing, for instance, is a breeze if you’re using IP Voice. So is setting up sophisticated UC solutions. In an IP ecosystem, collaboration tools do not seem like separate tools anymore, these get well-entrenched in regular work patterns, often going as far as to bring in a cultural shift towards a more collaborative way of working.

IP Voice in India

In Western markets, the main benefits of IP Telephony are cost savings, improved productivity, increased innovation and effective collaboration. The good news for enterprises in India—despite a different regulatory framework— is that most of these benefits are available to them too, albeit under slightly altered circumstances.

The Telecom Regulatory Authority of India (TRAI) has laid down detailed guidelines on VoIP. As far as Internet Telephony is concerned, calls are permitted when they are PC-PC; PC-overseas PSTN (using only service providers licenced to operate in India); or SIP-SIP (with no origination or termination with the Indian PSTN). Managed IP Voice, on the other hand, rides completely on PSTN outside the client organization, and hence is well within the regulatory framework.

For intra-organization Voice calls, some companies tend to use their corporate private network (typically MPLS-VPN). While this might seem like a “free” service, in reality it often isn’t. The traffic could be “data”, they still have to pay for that data. Moreover, the advantages of a managed service are unavailable in such instances.

In terms of both reach and infrastructure, India is largely ready to bring the benefits of IP Voice as end-to-end services to the doorsteps of enterprises. Reliance Communications, for instance, runs a nationwide Voice network purely to serve the IP voice requirements of enterprises. IP Voice Services in India are high QoS (Quality of Service) offerings ideal for corporate applications, unlike some markets where the services are significantly affected by the best-effort nature of the public Internet service, and consequently the user experience often leaves a lot to be desired.

With the arrival of SIP Trunking by Carriers like Reliance, businesses can now easily reap the advantages of IP Telephony for external communication. IP Centrex brings the advantages of IP Voice to enterprises without the need to invest in capex-intensive IP-PBXs and PRI cards.

SIP Trunking

Instead of a bundle of physical wires, a SIP Trunk link connects the IP-PBX over a single Ethernet port with the telecom service provider’s network via a Session Border Controller (SBC). In case of Reliance SIP Trunk, the core platform used is IMS class 5, resulting in the ability to provide virtually unlimited scalability without the need for new physical connections. SIP Trunking does not require a significant capital expenditure but immediately begins to reduce costs while maintaining the features that customers have with their local PBX.

Fig 1: Typical SIP Trunking Architecture

Large enterprises typically have multiple-location requirements with the objective of having a seamless and uniform Voice connectivity across locations within a controlled budget for intra-office communications. These enterprises would find immense value in bringing their Private IP Voice traffic on to a carrier’s PSTN via SIP Trunking while still retaining the cost advantage of private IP networks.

SIP Trunk is an attractive service for high capacity and traffic demands, particularly due to the cost savings that it immediately offers at the customer end. Organizations that have an IP-ready infrastructure (VAS operators, Cloud Telephony operators and BPOs/ Telemarketers) and Government departments with massive capacity requirements for bulk communication are good candidates for SIP Trunking.

We strongly believe that SIP Trunking will play a critical role in the “digital journeys” of enterprises. As enterprises continue to discover the possibilities that telephony can play in various stages of Customer Lifecycle Management, SIP Trunking will gradually come to the fore.

IP Centrex

By bringing the benefits of IP Telephony on a hosted-PBX model, IP Centrex offers a convenient gateway for enterprises of all sizes to enter the futuristic IP-centric world of Communications. It enables high-quality, feature-rich Voice communication for individual users in the enterprise, while equipping the enterprise with effortless manageability of its usage. The router/eSBC at the customer premises is connected to the Carrier’s IP Voice Network via the Managed IP Access Network, using dedicated circuits for bidirectional PSTN communication.

Fig 2: Typical IP Centrex Architecture

An IP telephony system usually comes with a very rich suite of features, and users love it. With these features, the telephone sheds its interruptive character and becomes more interactive, moulding its ‘behaviour’ in sync with the user’s preferences, location and engagements. Since the IP PBX—whether on-premise or hosted—is software-based, activating/deactivating and adding features is very simple. Similarly, configuration changes (adding, deleting, changing users, etc.) are usually just a matter of a few clicks.
Looking at IP Voice purely as a ‘two-party telephone call’ alternative is missing the forest for the trees. Of course, plain vanilla Voice—with HD quality often coming as a bonus—is a given in IP Voice, but the biggest advantages it offers are that it prepares us for the changing needs of businesses and gets us wired up for tomorrow.