Many businesses have already migrated to a VoIP as a Service (VaaS) solution due to the cost savings, reliability, simplification and flexibility involved.

This article discusses understanding VoIP as a Service in general, it’s benefits, various components and available design choices. This will allow you to make a more informed decision for the future telephony direction of your business.

An Overview of VoIP as a Service

VoIP (Voice over IP) is a method of transmitting voice traffic over the public Internet or a private network rather than using legacy PABX equipment over traditional and more costly voice capable ISDN lines.

VaaS goes one step further and allows your business to ditch on-premise physical or software PBX’s. Instead you can use a managed cloud based solution where the VoIP equipment, servers and services are all hosted and maintained by the VoIP provider who takes care of your calls, voice features and technical support.

The VoIP as a Service design model can save your business from the expense of investing in the actual voice equipment and the unnecessary burden on your IT team to maintain and support your voice platform.

Main Benefits of VoIP as a Service (VaaS)

1. Cheaper Calls

Both national and international calls can be sent over the Public Internet at a fraction of the cost. Call savings are on average 40% (when compared to analogue) and companies with high international calls can save considerably more.

2. No Upfront Costs

Save your business from the upfront expense of investing in the actual VoIP equipment.

3. Flexible Pricing

If your business has changes in staff numbers or you experience growth you can add or remove phone lines within minutes.

4. Cost Consistency

You pay a fixed fee per line per month so there are no nasty surprises

5. Greater Reliability

The hosted VoIP providers cloud will usually be located in a number of diverse data centres on different physical and virtual IP PBX’s with near-instant failover should issues arise.

6. Fast Provisioning

VoIP allows you to add additional phone lines easily within minutes via a provisioning portal.

7. Scalability

If your business has changes in staff numbers or you experience growth you can add or remove phone lines within minutes.

8. Additional Features

There are a multitude of features such as voicemail, call divert, hunt groups, Automated Call Distribution, Video Conferencing, Chat.

9. Management Simplification

Removes the unnecessary burden on your IT team of maintaining and supporting the VoIP platform. Leave the heavy lifting to the Provider and you use a simple remote portal for the simple management tasks.

10. Equipment Reduction

The only equipment you need in your business locations are physical VoIP phone handsets or you can use VoIP software (SIP client) on local computers/laptops.

Components of VaaS

components of voip as a service

Nest we will discuss the various components required for a hosted ‘VoIP as a Service’ solution.

1. Session Initiation Protocol (SIP)

SIP is the IP protocol used to transport voice traffic over an IP network thus allowing users to make voice and video calls mostly for free over the Internet or a private network. This protocol is used by the VoIP phones to communicate to the IP PBX for call registration and call setup/call teardown.

You may notice that many VoIP devices such as a VoIP phone are also called a SIP phone. The term VoIP and SIP do tend to be used interchangeably to describe the phones/handset.

2. Real Time Protocol (RTP)

RTP is the protocol that is used to transport the actual voice data over the network and works hand-in-hand with SIP that is used to register the phones and setup/tear down the calls

3. SIP Phone (aka VoIP Phone)

The SIP phone is the physical phone that sits on the users desk. Rather than connecting to the legacy BT wall socket it instead connects to the LAN switch. When booted up, the SIP phone uses the SIP protocol to register it’s number with the cloud PBX and confirm it is online for calls.

There is a huge selection of SIP phones on the market today. At present we recommend the Cisco SIP phone range as they are extremely stable and offer excellent call quality and user overall experience.

4. SIP Client (aka Soft Phone Client)

A SIP client is available for locations that do not require a physical phone. This is SIP software that runs on a PC or Mac to simulate a phone allowing inbound/outbound calls and all the same additional features possible with a physical phone handset.

Most users still prefer a physical phone but for hot-desking or locations that are hardly used then a soft phone client is an excellent choice.

5. Local Area Network (LAN)

You can simply plug in your new VoIP phones into your LAN switch and away you go. Ideally your LAN switches will have 2 features to get the best out of your VoIP service.

Using ‘managed’ switches rather than ‘un-managed’ switches can allow the LAN infrastructure to be configured to prioritise voice and video traffic using Class of Service (CoS). We can fully assist you with this aspect should you need.

The PoE (Power over Ethernet) feature allows your VoIP phones to obtain power from the LAN network cable rather than needing an additional power supply. This is an excellent feature that we recommend your current and future switches support.

6. Wide Area Network (WAN)

Each of your sites should have a good connection to the Public Internet or a Private MPLS network (more on this later) to ensure enough bandwidth for your voice and video conferencing traffic.

Your network provider should configure Quality of Service (QoS) on the WAN router to prioritise the voice and video traffic as it exits the router. We perform this by default for all our customers.

7. VoIP Cloud Provider

The VoIP Cloud Provider hosts the VoIP equipment on their own network and are responsible for the management and support of the entire VoIP platform. If there are any issues you would report them to the provider rather than troubleshoot yourself. You are responsible only for simple admin tasks and provisioning orders for new services/phones via the providers portal.


Your SIP Phones or SIP clients register with the Cloud Provider’s VoIP PBX to obtain their number and the establishment of all calls is via the Cloud Providers platform.

Models of VoIP as a Service

There are two main models to consider depending on your business needs:

1. Public Internet VaaS

Businesses who make mostly external voice and video calls rather than site-to-site should consider this model as it is quick to provision and has all the features you will need.

2. Private Network VaaS

If your company has multiple sites that will communicate between each other for voice and video, then a cloud hosted VoIP solution on a private MPLS network is highly recommended. All of your companies site-to-site calls and video conferencing data traverses a private high speed MPLS network rather than using the Public Internet which allows for better overall voice and video performance, monitoring and enhanced SLA’s.


VoIP as a Service (VaaS) is the way forward for businesses to enjoy reduced call costs, increased flexibility, scalability, simplified management plus additional call features such as chat and video conferencing. Understanding VoIP as a Service is an important first step towards making a more informed decision for your future voice requirements.

Please get in touch to discuss your VaaS requirements in more detail. We offer a completely free consultation with one of our technology experts to fully go over your precise needs.

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