SIP Trunking
Dialing telephone keypad

By Brian Ferguson

SIP Trunking is a phone service that allows companies to make and receive calls over their existing Internet connection, eliminating the need to use costly physical lines like PR1 or T1. It has changed the way companies pay for phone service. Today, more than 66 percent of companies have adopted SIP Trunking and are saving up to 70 percent off their monthly phone bill compared to their old PRI service.

While SIP Trunking is full of cost savings and calling features, it is also not without its hurdles. Let’s take a look at some pitfalls of SIP Trunking and the solutions that will help your company make a smooth transition.

1. Inadequate Bandwidth

SIP Trunking is dependent upon your company’s existing data connection. The bandwidth available in that connection is what makes the calls happen. Not having enough bandwidth to support the maximum concurrent calls made by your organization will result in dropped calls, busy signals, bad call quality and, ultimately, lost customers.

A simple solution is to get an Internet connection with more bandwidth. In most places, bandwidth is available and cheap. To make sure you have enough bandwidth to support the added load of your voice calls, use this formula: number of max concurrent calls x 100kb/sec (average bandwidth per call). This will give you the total bandwidth needed for your voice calls. Just add this to what you currently use to run your business to get your total bandwidth needed.

2. Not Understanding the Reality of Your Call Volume

Many SIP Trunking providers price their services by the minute. This pricing model is advantageous to companies with low call volume or dynamic call flows from seasonality or other sporadic events. The main benefit is that companies only pay for what they use. The problem lies with companies that don’t understand the reality of their call volume and end up paying more than they should.

Before you transition to SIP Trunking, analyze your company’s calling history. You’ll need to know how many minutes you use on average and how many concurrent calls you use at your busiest times. If your call volume is high, choose a SIP provider that offers a channelized plan that will give you unlimited minutes on a set number of trunks.

3. I Need My Numbers Ported Right Now!

Phone numbers or DIDs are valuable to most companies and an integral component of branding. The industry understands this and has made it a requirement for companies to “port” or move your phone numbers to whichever provider you choose. What they are not required to do is to port them quickly. This creates problems for organizations that are ready to save money, but can’t function without their numbers.

Most providers will allow you to forward your calls from one number to another. So get a new number from your new provider and forward your calls from your main numbers to the new one. Other than that, know you’re probably going to have to wait and wait.

4. Faxing Over SIP is Not an Exact Science

Fax machines still exist. Even with email, electronic signature technology and other options, the fax is hanging around, mostly in the medical community. Faxing has never been an exact science, even with dedicated analog fax lines. And faxing over IP has long been a thorn in the side of IT. A codec that was supposed to solve all the worries of the industry, T.38, has not succeeded.

If faxing is necessary and faxing over IP is a must, use a professional to help with setting it up. There are some tricks and phone system adjustments that can be made to help. If faxing is vital to your business, bring in some dedicated analog lines purely for fax. They’re cheap and work as well as fax can.

5. Voice Not a Priority

It’s likely that you have a lot happening on your data network. Between the systems you need to do business, email, collaboration, file sharing and, yes, some people watching YouTube videos, the traffic on your network is heavy. Today, without SIP Trunking, if there’s too much going on, you’ll likely see pages load slower, email takes longer to send and YouTube videos may not buffer correctly. When you add voice with SIP Trunking and there’s a lot going on, you get dropped calls and poor call quality.

For companies moving to SIP Trunking, it’s important to take advantage of a feature found in most business-grade network routers called Quality of Service (QoS). QoS is the traffic cop for your network and allows you to prioritize the traffic coming from key systems. With QoS, you can ensure that all voice calls will be handled first and with full bandwidth while the slowdown happens elsewhere.

Brian Ferguson is a product marketing manager at Digium, a business communications company that delivers enterprise-class Unified Communications. He has more than 15 years of experience working with a diverse range of technical solutions and brings a unique perspective in helping problem-solve for customers. Follow him at @brianpferguson.