Home / Business VoIP / Boundaries of Hosted VoIP Services

Boundaries of Hosted VoIP Services

Posted on

In my previous posts I had touched on the differences between traditional PBX and a Hosted VoIP service. Business VoIP solutions today come in all shapes and colors and also, unfortunately, under all kinds of names: Managed Hosted PBX, Hosted PBX, IP PBX, Virtual PBX etc. The names are used interchangeably as if they all mean the same thing causing confusion among buyers as to which product to use in what situation. Today I will try to explain what all these seemingly similar names mean and what is typically included and not included in each service, what the differences are between managed and unmanaged hosted services and where the boundaries of service provider’s responsibility lie in each case.

Not all managed services are created equal. Management responsibilities range from simple moves, adds and changes to fully outsourced management of the entire infrastructure of VoIP. Let’s take a closer look at some of those service tags:


Managed IP PBX simply refers to a PBX system that transmits voice packets as data over Internet Protocol. This system can be located on your organization’s premises or hosted by a service provider at a specially designed facility. While IP PBX system is owned by the enterprise no matter where it is located, all related day to day management responsibilities for configuration, operations and maintenance of your PBX lie with a 3rd party – service provider. Depending on your agreement with the service provider – network management responsibility may be placed on enterprise’s IT department or Service Provider.

Hosted PBX Service typically refers to VoIP application service provided to enterprise much like an email or website. All of the service infrastructure components are located at service provider’s facilities and may vary significantly their design and composition. It could be actual IP PBX platform or a softswitch. In both cases call control takes place within service provider’s network or in what is sometimes referred to as “the cloud”. Customer may choose service options and features that best suit their needs. Because this service is hosted – all of the responsibility for making service available and accessible lies with the service provider, be it a telecom carrier, systems integrator or a value added reseller.

Virtual PBX is essentially the same thing as a Hosted PBX without any call control features. It’s feature set is limited to forwarding calls and providing basic voice mail functions. As with the Hosted PBX service – Virtual PBX provider’s responsibility is to accept the call and properly forward it to a number specified by the client. Because the call has to traverse through the public switched telephone network (PSTN) – service provider does not control the infrastructure required for this call to be completed – his responsibility ends when a call gets forwarded. In other words service provider can not guarantee that such forwarded call from a virtual PBX service will be completed.

Why is it important to understand the architecture behind the service? Because many services have been tagged with names that do not accurately describe them. And with all the marketing hype surrounding VoIP technology – many service providers push the envelope by making claims of “fully managed service” without disclosing what is actually being managed until you get chance to see the fine print in a 20-page service contract.

Remember the old POTS lines or T-1/PRI channel banks ? Your (customer) responsibility always began at a point of “demarcation”. Phone companies had what they called a network interface (NID). You had the left side, they had the right side. Anything past the left side was your (customer) responsibility. Surely you could hire them to run the wiring inside your home or business for a hefty union rate or you could hire a contractor to run the wiring inside and connect it to the phone company’s service. When you had trouble, your favorite ma-bell sent a technician who would test the line from their side of the NID. And when they did not find a problem with their service – you, the customer, paid to find out what was wrong on your territory. Carriers have established boundaries that were clear, simple and, sometimes, unpleasant. But the important thing is that everyone knew what they were responsible for.

The truth is that Hosted VoIP services are typically a hybrid responsibility environment. The Service Provider is responsible for making service available while customer is responsible for being able to take advantage of the service. This means that customer’s network is designed and provisioned in a way that allows the customer to take advantage of the service.

Companies often underestimate the degree of readiness in the existing LAN and WAN to accommodate VoIP, and they underestimate the complexity of managing VoIP when it’s on the same backbone as data. What is even more important is that they don’t always understand that even if a service provider performed a readiness assessment and steps have been taken to bring their network in compliance with the service requirements – certain ongoing cooperation in change control is required between those who maintain customer’s network and those who provide VoIP service. As a company grows and adds more users and advanced features that require more bandwidth and less latency such as video calling and conferencing, its network must also be capable of accommodating those needs.

What’s important to understand here is that with Hosted VoIP there are always two separate sets of SLAs. Those that require for the service to be available and accessible, and those that ensure that company’s infrastructure required to access the service is in place. And responsibility for meeting those is mutual between the customer and his service provider. This means that unless service provider is fully responsible for customer’s network, the customer must make sure that his network meets service’s bandwidth and latency requirements.

In a traditional circuit based network voice is given a dedicated bandwidth allotment so the quality is assured. In a packet environment one must either predict voice quality in a new VoIP deployment or assess voice quality in an existing network to ensure end user satisfaction. Both scenarios can be managed.

Sometimes businesses buy into a promise of “fully managed service” by purchasing their bandwidth from their Hosted VoIP Service Provider while retaining full change control over their hosted service. In reality full end to end management of the VoIP service requires complete delegation of service change management. This allows service providers to always assess company’s network prior to enabling access to the new services. But the fact of the matter is that there is nothing wrong with unmanaged Hosted VoIP/PBX service as long as there is a clear understanding of the accountability and responsibility by all parties tasked with ensuring service quality and usability.

VoIP technology introduces complicated technical issues and concerns over security and quality of service (QoS). To address these concerns effectively – hosted VoIP service providers must adopt one of the two models: they shall either provide full end to end management of the network services or, more commonly, clearly communicate the service requirements and boundaries of their responsibility ensuring that customers understand what they must do to make use of hosted VoIP technology.

The industry often chooses to focus on the positive features of VoIP — shared IT infrastructure, and plug-and-play adaptability. While these key elements take advantage of the flexibility of IP, they are also what make it more susceptible to possible problems. Unlike a traditional TDM network, a VoIP network is vulnerable to the typical IP infrastructure issues, including interference from denial of service (DOS) attacks, viruses and worms. These attacks can lead to the major outages that sometimes occur with data networks – taking the network down for hours or even days.

The good news is that VoIP has now been around for many years and most of the risks can be easily mitigated by adopting best practices models for an individual company. IT departments and Network Solutions providers continuously develop tools, techniques and practices for protecting and controlling VoIP networks. Successful cooperation of all parties involved in service delivery and clear understanding their responsibilities and service boundaries are important contributing factors in any Hosted VoIP deployment.

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Top