Voice over IP has been commercially available for businesses for over two decades.  Today, it is considered a robust, reliable, and flexible technology, and it is the technology of choice for any new telephony installation.  Nevertheless, like any modern application or service, it can present some challenges when being deployed and must be implemented appropriately to avoid costly potential pitfalls.

In this article, we’ll examine the advantages and disadvantages of VoIP-based applications and services. We’ll also outline some of the most important best practices to keep in mind to ensure that your VoIP deployment satisfies your business needs and even exceeds expectations of what a telecommunications system can and should deliver.

What is VoIP?

The term VoIP is used to refer to a whole series of technologies that are employed to deliver voice services over IP networks. 

VoIP is not a service in and of itself but is an umbrella term that encompasses protocols, codecs, techniques, equipment, software, and many other aspects of telecom services.

You can find much more about VoIP in this article about VoIP phone systems. Still, for this article, it’s enough to say that VoIP is what enables us to transmit voice over a packet-switched IP-based network successfully.

What are the Advantages of VoIP?

Around the turn of the century, businesses would typically maintain two discrete and disparate networks: the data network and the voice network.  This was because these two technologies developed separately and, as a result, were incompatible.  Along came network convergence and changed all of that.

VoIP is the fundamental enabler of network convergence because it defines rules, methodologies, and techniques to transmit voice over IP networks.

Due to this convergence, voice and data now share the same underlying network infrastructure, and this fact is arguably the single most important characteristic that delivers the phenomenal advantages of VoIP.  These advantages are further detailed below.

Software and IP network-based

Unlike the traditional telephone, VoIP services follow a client-server model and rely on IP networks to deliver connectivity between the client and the server.  This allows VoIP to enjoy the same advantages that data networks and services deliver.  These advantages include:

  • Software-based IP PBX – VoIP servers, or IP PBXs, can be deployed in much the same way as other network application servers. They can be installed on a physical server in your datacenter, as a virtual machine, or even within the cloud, making deployment and management much simpler and more streamlined.
  • IP-based connectivity – VoIP clients must connect to the IP PBX to function. If you ensure that the IP PBX is reachable over the Internet, then clients need only be connected to the Internet to operate successfully.  They are no longer confined to the same physical location as the IP PBX.
  • Cloud-based advantages – VoIP can take full advantage of the benefits delivered by cloud-based deployments.  Software as a Service (SaaS) is a very popular deployment model for many VoIP services, such as RingCentral.

Voice services essentially become one more application deployed on the IP network.

Financially attractive

Another benefit that is a direct result of this network convergence is cost savings.  The network convergence that VoIP enables means that enterprises need to maintain a single network.  Consolidating all telecom services into one network introduces cost savings by eliminating infrastructure duplication and streamlining ICT personnel and skillsets.

Additional cost savings come from the fact that VoIP can be deployed on already existing endpoints, including mobile smartphones, laptops, and desktops, in the form of software rather than requiring the use of an often-expensive physical telephone.

The fact that VoIP is primarily software-based also enables enterprises to deploy voice services in a cloud-based model, vastly saving on data center hosting costs as well as on the use of dedicated telephony switching hardware.

Freedom of mobility

With the integration of VoIP software on mobile smartphones and tablets, it is possible to remain connected to your voice call services no matter where you are.  With virtually ubiquitous Internet connectivity available worldwide, you can literally carry your office landline in your pocket.

Such mobility is very important, especially in today’s rapidly changing workplace environment. By some estimates, 1.87 billion people worldwide (about 42% of the global workforce) are already working as mobile employees, and this trend is expected to increase. 

VoIP technology delivers unprecedented flexibility in mobility, allowing employees to use their office phone number and related voice services from home, from a remote branch office, on the go, or literally anywhere in the world where Internet connectivity is available.

A multitude of features

VoIP’s software-based nature means that VoIP technology itself is not limited to simply delivering telephony services.  VoIP has evolved extensively over the past two decades, vastly outstripping the rate of development that traditional telephony experienced.

VoIP technology allows deep integration of voice services with many highly advanced business productivity applications, including contact centers, CRM services, video conferencing, voicemail, and collaboration applications, as well as highly specialized software suites.  Services such as ZoomPhone combine telephony with videoconferencing features, while platforms such as GoToWebinar deliver highly specialized webinar services integrated with telephony features.

VoIP continues to evolve and develop, delivering many voice-related business productivity services based on the everchanging needs and requirements of businesses both today and in the future and increases the opportunity for scalability.

What are the Disadvantages of VoIP?

Having lauded the benefits of VoIP so vehemently, it seems counterintuitive to refer to some of the disadvantages of the technology.  These are not so much disadvantages as they are potential pitfalls inherent to VoIP that must be highlighted, considered, and appropriately mitigated.

Quality of Service

IP data networks are what are known as “best effort” networks, where individual packets are routed to their destinations on a first-come, first-serve basis.  This means that individual packets that are part of a data stream between two hosts are subject to various phenomena that affect data flow. 

Individual packets may arrive at their destination with some delay (latency), multiple packets may arrive with a continually varied latency (jitter), or they may arrive in a different order from which they were sent.  Packets may also be lost, requiring upper-layer protocols requesting data retransmission.

All these phenomena are well-known and accepted realities for data networks.  Services such as email, web browsing, file transfer, and other more traditional applications suffer little or no service degradation from these occurrences. 

However, the quality of voice services is highly affected by these behaviors.  Data networks were not originally designed to deliver the network characteristics needed by VoIP services.  If these issues are not addressed, it could result in a degraded quality of voice services.


Unlike traditional telephony service, which is extremely difficult to hack, VoIP introduces many more attack vectors, making it more vulnerable to malicious online users.  VoIP inherits virtually all of the security vulnerabilities that are characteristics of data networks and services.  IP PBXs, client software, as well as VoIP infrastructure, are all potential points of entry for those seeking to compromise a voice system or a simple phone call.

Reliability of Infrastructure

VoIP requires a reliable, sufficiently fast Internet connection to operate.  Within an enterprise environment, this is usually delivered successfully, but for those working from home, from their local coffee shop, or while traveling, reliable Internet connectivity is only sometimes ensured.

This reliability must also take into account power considerations.  In the event of a power outage, will Internet connectivity still be available?  Once again, if you’re working within your enterprise’s HQ, you will likely not have any problems, but what if you work from home, at a coffee shop, or somewhere else on the go, will a power outage disrupt your VoIP service? Or what happens if your smartphone or laptop battery dies and you cannot access an electrical outlet?  These must all be considered potential limitations to the operation of VoIP-based services.

What are best practices when using VoIP?

So far, we’ve seen the advantages of using VoIP technologies, and we’ve also examined the potential drawbacks that the technology can introduce to your telecom services and network.  As stated before, the disadvantages are highlighted here not because they are insurmountable obstacles to using VoIP but because they are considerations that must be addressed successfully to enjoy a fully secure and functional telecom service.

These best practices reveal how to mitigate the drawbacks that VoIP can introduce, ensuring you have a functional and secure telecom system serving your organization.

Employ industry-standard QoS mechanisms

Over the years, the need for IP-based networks to deliver network capabilities required by VoIP services has led standards organizations and vendors to develop quality of service (QoS) mechanisms.  These are configurable features of network devices that can prioritize voice packets to reduce and, in some cases, eliminate latency, jitter, packet loss, and out-of-order packets, ensuring high-quality voice services.

Within an enterprise network, the QoS mechanisms and parameters recommended by VoIP providers should be employed across all network devices.  Similarly, QoS should be employed on WAN links as well as any private or shared networks.

It is important to note that QoS mechanisms cannot be used over the Internet.  Even if packets are marked with a particular priority, these priorities are stripped when sent over the Internet. 

For this reason, it is important to ensure that you are using a high-bandwidth Internet connection that will not suffer network congestion from data services that may be sharing that same connection.  Of course, this is only sometimes possible, especially if you are connecting using a network that you do not own, such as a Wi-Fi network in a coffee shop or at the airport.

Safety and security best practices

Although VoIP indeed introduces more attack vectors than traditional telephony technology, this by no means makes using VoIP a bad choice.  Like all network services, the appropriate security measures must be taken to protect your telecom network.  VoIP security is a mature and robust discipline and when employed correctly, can deliver a safe and secure voice network. 

Some of the aspects of these security measures include:

  • Network security parameters – Ensure that the network has been designed with appropriate network security characteristics. This can include a multitude of generic network security best practices including the employment of firewalls, intrusion protection systems, network segmentation, access control and application security.
  • Military-grade encryption – Many modern VoIP services deliver integrated VPN features that ensure that server-to-client, as well as client-to-client communications, are encrypted using military-grade encryption mechanisms. Even if such a communication is intercepted, it is unintelligible and ultimately useless to any phone call eavesdropper.
  • Train users – One of the most often neglected areas of network security for both VoIP and data services is user training. Users of VoIP services must be educated as to how they should manage their passwords, personal information, accounts and from which devices they should and shouldn’t connect.

VoIP security is not a discrete and separate discipline and should not be approached independently from other security concerns.  It must be examined as part of a holistic network security policy that affects all aspects of network service usage for an enterprise or individual users.

How to choose the appropriate VoIP provider?

Whether you are using VoIP as an individual, as a small business, or as part of a large organization, one of the most important best practices is choosing the appropriate VoIP provider.  Voice services come in many different forms, and best practice dictates that you must first determine and clearly articulate the needs of the organization in question.

Voice services have many different forms, and the entity’s requirements play a large role in what you ultimately choose.  Some of the variety of choices that are available to choose from include the following:

  • IP PBX/VoIP server
    • Standalone physical appliance
    • Software installed on a physical server
    • Software installed as a virtual machine
    • Software installed on cloud infrastructure
    • Subscription service that can be purchased as a SaaS
  • VoIP clients can be delivered as one or more of the following:
    • IP desk phone
    • Softphone installed on a desktop or laptop
    • Mobile app installed on a smartphone or tablet
    • Web-based application/softphone used via a browser
  • Additional equipment and services can include
    • VoIP gateway connecting the voice network to the PSTN via a SIP trunk
    • Contact center server for customer service capable of creating call queues, announcements, call routing, and advanced call handling scenarios
    • Integration of videoconferencing and collaboration platforms that enhance voice services and improve employee productivity

Knowing the various deployment methods, as well as the additional services that exist, will aid you in determining the best arrangement to deliver your particular telecommunications requirements.


VoIP technology offers a vastly improved set of features and services for today’s highly adaptable and continually changing businesses.  Understanding the advantages of VoIP, the potential pitfalls of its deployment, and the best practices that mitigate against those pitfalls is of utmost importance to ensure that your organization enjoys the best possible set of telecom services.