The difference between VoIP and SIP trunking

As technology develops what we find is that we are subjected to more and more acronyms. Even with the tech of old, there are few of us who know exactly what every acronym stands for when it comes to telephone systems. That being the case, it is perhaps unsurprising that there are many who are slightly out of touch with the newer terms. That is why we are often being asked about SIP vs VOIP and what the differences actually are.

Sure, no doubt you’ll have heard the terms SIP and VOIP banded around the office when talking about communication systems, but the chances are no one quite knows what they are. Even more likely is that no one really knows the difference. Let’s go ahead and change that now.

What is VOIP?

Let’s clear up this acronym first. VOIP stands for Voice Over Internet Protocol. What this means in basic terms is that this technology allows sounds (more precisely, your voice) to be carried over the internet. Although VOIP is the most popular term for this technology, you may find some that refer to it as broadband telephony or internet telephony.

Regardless of what it is referred to as, and regardless of the software or hardware being used, if your voice is travelling over the internet you are using VOIP.

What is SIP?

The second of our acronyms, SIP stands for Session Initiation Protocol. A protocol is effectively a language that is used by computer hardware. You need your computer and your computer’s modem to be speaking the same language to allow them to communicate.

There are a variety of protocols that are used to deploy VOIP and allow that communication to take place. SIP is just one of these however it is the most widely used. The fact that SIP is used more often than not in a VOIP setup leads to the terms being used interchangeably when there is, in fact, a difference.


There are plenty of people who consider SIP vs VOIP as they consider the two as something that can be compared. The truth is that they are not true comparables as they have a relationship with each other. Now we know what each of the terms means, it is worth exploring that relationship so that you can have a better understanding of how they work.

When considering the relationship between SIP and VOIP it is comparable to the relationship between websites and HTML. A website is just a collection of pages that appear on the internet that can be accessed by a web browser. HTML is one of the available codes that can be used to create these sites in the first place. However, there are other languages that developers may choose for websites such as Java.

That relationship works the same with VOIP and SIP. VOIP is the webpage. It is any method that is used to send voice over the internet. This could be through Skype, Zoom, or FaceTime on one level or a business phone setup on another. SIP is like HTML. It is one available protocol to use with VOIP, but not all VOIP services utilise it. Just like the web developer that opts for Java, VOIP providers have the freedom to use other protocols.

VOIP only vs VOIP and SIP

Rather than any comparisons being about SIP vs VOIP, the true comparison that can be made is between opting for VOIP or VOIP with SIP. If within your business, you are only reliant upon voice calls then there is no real need to explore it with SIP. VOIP will deal with voice calls and requires next to no installation. . With a basic VOIP setup, you can also access features such as caller waiting and caller ID.

The reason that businesses opt for VOIP with SIP is that SIP brings additional features into the mix. With SIP you can:

  • Integrate multimedia channels
  • Make voice calls
  • Make video calls
  • Transmit conference calls
  • Be assured of flexibility
  • Have the security of a fallback option if your internet fails

Hosted VOIP vs SIP trunking

If people stop to consider VOIP, the majority are familiar with hosted VOIP. In these cases, a vendor manages all associated components with the setup and phone services are delivered to the clients’ internet. These services are popular as it means that there are no concerns in terms of maintenance or repairs. There is also no need to purchase any expensive hardware to get you up and running.

With SIP trunking, phone services are delivered to a business with their own IP PBX. It acts as a bridge between the public service network and VOIP. It is a virtual connection rather than being an actual physical line. The provider of SIP trunking is responsible for ensuring that you are connected and have a dialling tone. Everything else is down to you. This means that you get to choose the features that you activate, but you are also responsible for maintaining the system. SIP trunking tends to be the favoured option for businesses with high call volumes.

What should my business choose?

When it comes to deciding between hosted VOIP and SIP trunking, there are several factors to consider. These include:

Your budget

Hosted VOIP has much cheaper setup costs when compared to SIP trunking. However, in the long-term SIP trunking will often work out the cheaper option. If you have the funds for the initial outlay, then it makes sense to opt for SIP trunking.

The needs of your business

There are plenty of hosted VOIP services and so it is likely that you will be able to find one that covers the needs of your business. However, if you want full control over the features, and you want your service to remain one that can be customised, then SIP trunking is the way to go.

Expertise within your business

With hosted VOIP you are safe in the knowledge that all issues will be taken care of by your service provider. With SIP trunking, you are likely to need a team that can manage and maintain your service.

Speak to the experts

At Landall Services, we can advise on the best system for your business. No matter what the size of your organisation, we have options that will work for you. Get in touch today and see how we can help.

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