What is Voice Over IP (VoIP)?

What is Voice Over IP

VoIP is the transmission of sounds, voices, and multimedia content over IP. VoIP is an acronym for Voice over Internet Protocol.

An example of Internet Protocol networks is the Internet. VoIP is also called IP telephony(Internet Protocol telephony)                 

The terms broadband telephony, broadband phone service, and  Internet telephony specifically refer to the provisioning of communications services over the public Internet.

These communications services include voice, fax, SMS, and voice-messaging, etc.

The communications services are provided over the public Internet rather than via the PSTN (public switched telephone network).

The PSTN is also known as POTS (plain old telephone service). 


The principles and steps involved in originating VoIP (Voice over Internet Protocol) telephone calls are similar to traditional digital telephony.  The principles and step involve channel setup, signaling, encoding, and digitization of the analogue voice signals.

Digital information is packetized, and transmission occurs as IP packets over a packet-switched network instead of being transmitted over a circuit-switched network. They convey media streams using special media delivery protocols that encode video and audio with video codecs and audio codecs.

Several codecs exist that optimize the media stream based on network bandwidth and application requirements. Some implementations rely on compressed and narrowband speech, while others support high-fidelity stereo codecs.

The most popular speech coding standards in VoIP are based on the modified discrete cosine transform (MDCT) and linear predictive coding (LPC) compression methods.

Popular codecs include the LPC/MDCT-based Opus (used in WhatsApp), the MDCT-based AAC-LD (used in FaceTime), A-law, and μ-law versions of G.722, G.711, and the LPC-based SILK (used in Skype).

Early providers of VoIP services use business models. They also offered technical solutions that depict the architecture of the legacy telephone network.

Second-generation providers built closed networks for private user bases, offering the benefit of convenience while certainly charging for access to other communication networks. An example of this communication network is the Public Switched Telephone Network (PSTN).

Third-generation providers, for example,  Google Talk, adopted the concept of federated VoIP(Voice over Internet Protocol). These solutions mostly allow dynamic interconnection between users in any two domains of the Internet, when a user wishes to place a call.

Furthermore, VoIP is also available on many PC’s (personal computers) and other Internet access devices. SMS text messages and Calls may be sent via the carrier’s mobile data network or Wi-Fi.

VoIP (Voice over Internet Protocol) provides a structure for the consolidation of all modern communications technologies using a single unified communications system.


VoIP has been executed with proprietary protocols and protocols based on open standards in applications such as web-based communications, VoIP phones, and mobile applications.

The following are the protocols of VoIP:

  • Session Initiation Protocol (SIP) is a connection management protocol. It is developed by the IETF (Internet Engineering Task Force).
  • H.323 is one of the first Voice over IP call control and signalling protocols that found widespread implementation. H.323 deployments became increasingly limited to carrying existing long-haul network traffic since the spread of newer, less complex protocols such as SIP and MGCP.
  • Media Gateway Control Protocol (MGCP) is also connection management for media gateways.
  • Gateway Control Protocol (H.248, Megaco) is a control protocol for media gateways across a converged internetwork consisting of the modern packet networks and traditional PSTN.
  • Real-time Transport Protocol (RTP), is a transport protocol for video data and real-time audio.
  • Real-time Transport Control Protocol (RTCP), which is a sister protocol for RTP(Real-time Transport Protocol) provides status information and stream statistics.

A variety of functions are needed to execute VoIP (Voice over Internet Protocol) communication. Some protocols perform a few functions, while others perform multiple and must be used in concert.

These functions include:

  • Session management: Managing and creating a session, which is a connection between two or more peers that provides circumstances for further communication.
  • Network and transport – Creating genuine transmission over ungenuine protocols, which may involve accepting receipt of data and retransmitting data that wasn’t received.
  • Signaling: These involve performing registration (such as advertising one’s presence and contact information) and discovery (such as, locating someone and obtaining their contact information). Signaling also involves dialing (for example, including reporting call progress), negotiating capabilities, forwarding/transfer. Also, it involves making call control (such as mute, hold, dialing DTMF keys during a call [for example, to communicate with an automated attendant or IVR],  etc.).
  • Media description: This means determining what type of media to send (video, audio, etc.), how to decode/encode it, and how to receive/send it (ports, IP addresses, etc.).
  • Quality of service: This refers to providing feedback or out-of-band content about the media such as statistics, synchronization, etc.
  • Media: These functions mean transferring the actual media in the call, such as video, audio, files, text messages, etc.
  • Security: Security involves verifying the identity of other participants (people or computers), implementing access control. Furthermore, it includes encrypting data to control messages or protect the integrity and privacy of the media contents.
  • Secure Real-time Transport Protocol (SRTP) also a protocol of VoIP. It is the encrypted version of RTP(Real-time Transport Protocol).
  • Session Description Protocol (SDP), is a syntax for session initiation and announcement for WebSocket transports and multimedia communications.
  • Inter-Asterisk eXchange (IAX), is the protocol used between Asterisk PBX instances.
  • Protocols of VoIP also include Extensible Messaging and Presence Protocol (XMPP), Presence information, Instant messaging, and contact list maintenance.
  • Jingle, for peer-to-peer session control in XMPP.
  • Skype protocol, a proprietary Internet telephony protocol suite based on a peer-to-peer architecture

Benefits of Switching to VoIP

Voice over IP offers several financial benefits when compared to a local telephone company’s service.

Three unique features are standing out for companies with call centres, growing long-distance bills, or a large office workforce when comparing VoIP to a local telephone service.

They include:

  • Increased productivity: Voice over IP increases worker productivity by integrating voice calls with unified cloud collaboration platforms, communications, and business intelligence applications.
  • Reduced phone charges: VoIP uses the Internet to conduct voice calls. As a result of these, VoIP can establish connections to anywhere in the world without incurring long-distance charges. Traditional phone service, on the other hand, would charge high for calls placed to different landlines. One of the merits of VoIP is that calls made within the same service provider’s network are free no matter the distance between the calls. For calls placed to different landlines or networks, calling costs are much lower than traditional phone services.
  • Better scalability: For traditional phone systems to support a certain number of users at a location, it requires equipment installed on-site to function. Voice over IP can be scaled up as a business grows much faster at less cost.
  • Connect multiple offices: For businesses that want to span numerous locations across one or more countries, such businesses can find traditional phone service a logistical headache. Connecting numerous offices is an important area where VoIP is really useful. Voice over IP allows businesses to combine the phone systems of multiple offices of an organization to a single system.
  • Save on outmoded phone systems: Traditional landline phone service requires expensive maintenance of on-site equipment. Also, we need equipment upgrades always to increase the number of available lines. On the other hand, this maintenance is eliminated by VoIP (Voice over Internet Protocol), because it uses the location’s existing local area network.
  • Broadband internet service: Most organizations have the bandwidth and internet infrastructure to switch to VoIP( Voice over Internet Protocol). Most call centres might require an increase in bandwidth to a location, but Voice over IP usually doesn’t require major upgrades.
  • Overcoming geography: International organizations face the unique challenge of merging teams spanning two or more countries. Voice over IP can make bridging the geographical divide much easier when included in a larger technology package for managing remote teams.
  • Managed VoIP services: Managed service packages like Epik offers all the software and hardware needed as a complete service package for a simple per-user monthly charge. Offers like these take out the headache of switching to VoIP for businesses that want to avoid the expense of purchasing and owning VoIP hardware themselves.

Disadvantages of using VoIP

The disadvantages of replacing a traditional phone system with VoIP relate to the dependency of the internet technology that it relies on to deliver voice calls.

Besides, the most common cause of VoIP quality issues is related to bandwidth limitations and the Internet.

Whether it is the difficulties that an unreliable internet connection can create or the increased cost of electricity, VoIP does come with a few drawbacks.

The following are some of the possible drawbacks to be aware of when choosing a VoIP service.

  • Need for a power source: After all, traditional telephones are powered with electricity which is supplied through a landline, this means it can function during local power outages. The electricity which is supplied through a landline is delivered by the local telephone company. On the other hand, VoIP devices use power from a wall socket, which means they can fail during local power outages unless emergency power is available. For an organization, the need to supply power can result in an increase in its utility bill as a result.
  • Call quality: There are quality issues that can happen with VoIP, for example, excessive delays or noise when placing calls on the line that we usually don’t encounter with landlines. When these issues come up, they can be difficult to track down because they may be caused by insufficient bandwidth, poor internet service, the VoIP service provider. The problem might even be caused by VoIP’s hardware.
  • Security: Another disadvantage of technologies like VoIP is the boundless security risk of sending data over a public network. Many Hosted systems and VoIP phones are designed to encipher the voice data they send over the Internet to protect against harmful eavesdropping. Nevertheless, organizations that are concerned about the potential loss of privacy should examine security closely when considering a VoIP service.
  • Consumes internet bandwidth: VoIP will add a bandwidth load to your existing internet service because it operates over a broadband internet connection. Large organizations may need to increase their bandwidth to be able to accommodate the data usage that a new VoIP service will require. Many Voice over IP providers like Epik offers unlimited bandwidth with a set of fibre optic internet plans to solve this problem.
  • 911 emergency calling: Another demerit of using VoIP is that it doesn’t have a provision for 911 emergency calls. Voice over IP has not been required by regulators to offer a connection to 911 service.

Getting the Best VoIP Experience

There are various ways an organization can get the most out of VoIP. Here’s are a few ideas to optimize the benefits of VoIP:

  • Responsive support: An important aspect of VoIP service that we can benefit more from, is the responsiveness of the customer support offered by the service provider. Look for providers who guarantee resolution and response times and who provide multiple channels of contact, such as phone, social media messaging, and online chat.
  • Up-time guarantees: When choosing a managed or hosted internet service, an uptime guarantee is an important thing to consider. With the birth of cloud technologies, these guarantees have been pushed as high as 99.8% by some service providers. The reason the guarantees were pushed high was that they could restore service with backup servers and quickly respond to outages. We should be sure to choose a service provider that stands by its guarantee.
  • Hosted Voice over IP (VoIP) solutions: Modern hosted solutions make use of the cloud servers to provide the connectivity they need to manage a site’s VoIP service. Replacing the resources needed for the number of users required is a simple process of changing server settings, or subtracting or adding cloud servers. It also makes a recovery from hardware failures reliable and fast.
  • Fibre optic internet service: Fibre optic internet services like Epik’s FIBERLINK allows organizations to operate their own private network that connects disparate locations to the Internet. These dedicated network connections are managed and maintained 24/7 by the service provider. The reliability and bandwidth of a private fibre-optic network are much higher than standard broadband internet connections. A private fibre-optic network allows our VoIP data to travel unobstructed and securely, avoiding public internet traffic.
1 comment
  1. I appreciate what you said about how VoIP systems can operate on private networks. I need to get a conference calling software for the office. I’ll have to order something online.

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