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Part II: What Matters Most in a SIP Trunk Provider?

Posted by Cherie L. Steffen on April 9, 2015 at 9:00 AM
Cherie L. Steffen

A few months ago, we shared with you an informative post titled What Matters Most in a SIP Trunk Provider? Now, Software Advice, a free online tool for researching VoIP software, just released the second half of their 2015 SIP Trunking report. The data was so extensive that they had to create two reports! Working with their research partner, Lightspeed GMI, Software Advice gathered 208 responses from random IT decision-makers over a five-day survey consisting of 30 questions.

We’ve worked closely with Software Advice over the past couple of months to present to you the most up-to-date research conducted in the VoIP industry. Remember such articles as What is the Ideal Phone Setup for Your VoIP System?, Free Communications Apps, Switching to VoIP, and Telecommunications Search Trends? Well, we’re doing it again with this post. Settle in as we present to you Part II: What Matters Most in a SIP Trunk Provider? For the complete article, please click here.

A Quick Overview

As we mentioned in Part I, SIP, or Session Initiation Protocol, is an Internet-based service that connects local and long-distance calls to and from traditional phone networks. If the person you’re trying to call is still using a traditional phone system, you’re going to need a SIP trunk provider to connect the calls. This review will touch upon the major factors IT decision-makers think about when selecting a provider. Matters such as security options and service level agreements (SLAs) and how they relate to SIP trunking installation and maintenance will be covered.

On-Premise PBXs Are More Dependable Than Cloud-Based For SIP Trunking

The survey demonstrated that there are several benefits of using an on-premise solution along with SIP trunking. More specifically, if businesses choose to go with an on-premise PBX phone system, they can improve its reliability. Out of all the respondents, only 53% of those with on-premise systems report that service outages happen “often” or “very often.” That number rose to 60% when the respondents had cloud-based systems.

There are many reasons, technologically speaking, why there are variations with the outage frequency. One such reason is if an organization has on-premise servers, those servers will have more of a direct connection to PBX applications. Those PBX systems offer backup connectivity options. If their Internet service goes down, calls can be routed over the traditional phone network.

Please take a look at this chart below to see the outage frequencies by type of PBX system.


Simple Configuration, In-Depth Support for Cloud PBXs Offered with SIP Trunks

We’ve learned from our respondents that when used with cloud-based systems instead of on-premise, SIP trunks support a greater range of PBX features and functionality. There are also compatibility issues that cloud users are able to avoid unlike the users of the on-premise systems. 4 percent of the group who use on-premise systems say their existing PBX systems and SIP provider are completely incompatible. If you’re going to build a system from scratch, it may behoove you to look into a cloud-based PBX system to avoid any compatibility and configuration headaches.

Take a look at the chart below to see cloud vs. on-premise PBX features supported by SIP trunking.


Great Majority of Respondents Find Satisfaction with Their SLAs

One way you can help yourself out and lessen maintenance and configuration issues is to choose a SIP provider that has the SLAs you need for your business. As a reminder, SLAs are contracts that state the levels of service organizations will expect from their SIP providers.

Four important types of SIP trunking these SLAs relate to are:

 Installation – Ensures that the installation will be complete within a certain time frame.
 Mean time to recovery (MTTR) – Ensures the provider will take an fixed (average) amount of time to have the service up and running after and outage.
 Mean opinion score (MOS) – This is a rating scale for the subject experience of audio quality.
 R-Factor score – A sophisticated, alternative scale for measuring call quality.

See the chart below which shows the prevalence of SLAs.


Installation SLAs slightly beat the MTTR and call-quality SLAs, but otherwise, there was nearly an equal level of occurrence for all SLAs mentioned.

As you’ll see in the picture below, on average, it was found that most providers stick to the ongoing MOS/R-Factor and MTTR SLAs they offer.


Managed Routers, Session Border Controllers Adopted by Great Majority of Respondents

Selecting a managed hardware plan from your SIP provider is another way to facilitate the SIP trunking deployment process. The IT-decision makers who responded to the survey adopted the managed-router and session border controller (SBC) plans at a high adoption rate, with managed-routers edging out the SBC plans by 8%.

See the chart below for an illustration of the adoption plans.


Looking at the survey results, most businesses would seem to benefit from at least one of the plans. Overall, it’s best to determine which kind of plan will meet your organization’s needs best.

For Security of SIP Trunks TLS is the Top Solution

Lastly the survey participants were questioned about the security measures their businesses use. Yes, session border controllers are in favor with the respondents, but not as much as other methods where securing SIP trunks are concerned. Below are a couple SIP trunking security measures we’re going to discuss:

 TLS – A protocol for encrypting IP communications, used for purposes such as securing transmission of payment card information and also VoIP security.

 VPNs – A private network that can be created by hard-wired or direct wireless connections between devices.

There are also several types of VPNs, but today, we’re looking at these:

 Internet Protocol Security (IPsec) VPNs: This is a type of VPN often used in connection with VoIP to enable video conferencing and secure voice calling.

 Multi-protocol Label Switching (MPLS) VPNs: This is a type of VPN supported by an MPLS network. In these networks, data packets are assigned labels that control how they are routed between network nodes (such as switches and routes).

Please see the following chart to view the SIP trunking security measures.


As you can see from the chart, the VoIP security measures that are currently available are quite a distance away from being universally adopted. Organizations should be sure that any potential providers they choose will support the security options that are in their best interests.


As a recap, we come away with five main key points concerning IT decision-makers and what they consider when selecting a SIP Trunk provider:

♦ Cloud based systems have more SIP provider outages than on-premise systems.
 On-premise systems are less compatible with SIP providers than cloud systems.
 Uptime, call-quality, and installation guarantees concerning SLAs deliveries were met.
 It’s wise to invest in managed hardware plans.
 The most widely adopted VoIP security mechanism is TLS.

As you can see, there is a lot of information presented in this post, but there is even more in the original study. Take a few moments to head over to their site to read it in full. In the meantime, to be sure you don’t miss any of our VoIP Innovations’ posts -- please subscribe to our blog and get them delivered right to your inbox!
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Tags: VoIP, Entrepreneurship

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