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What is SIP Trunking and Why Do I Need It?

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You're not alone if you’ve considered switching to SIP trunking—it's a popular upgrade option to a company's phone system, and for good reason. But with a whole alphabet soup of terminology surrounding it, from PBX to DID to PSDN, it's no wonder so many ask the question, "what is SIP trunking and why do I need it?"

In this blog post, we'll run through SIP trunking 101, break down the terminology surrounding it, and lay out five major benefits to explain why SIP trunking is such a popular telephony solution.  

What is SIP Trunking?  

SIP trunking uses an internet connection, rather than a traditional phone line, to operate company phone systems. In other words, it allows direct connection to the PSTN (Public Switched Telephone Network, or traditional phone lines) through IP/Broadband.  

What is SIP trunking not? Elephants sipping water with their trunks

A SIP trunk is installed virtually over an internet connection, creating a single entry point. Hardware and wiring aren't necessary because the need to physically connect to a phone company is eliminated.  

SIP (Session Initiation Protocol) is a standard protocol in a UC (Unified Communications) solution and is used to enable signaling functions for VoIP (Voice Over Internet Protocol) and telephony in general. SIP and VoIP are not the same thing, but they both contribute to the same goal of connecting calls via the internet.  

SIP trunking's "trunk" refers to circuit-switching telecommunications lines, but unlike traditional lines, it's virtually connected using a dedicated line.   

SIP trunking is often a replacement for ISDN (Integrated Services Digital Networks), a telephony option designed to handle voice and data on a single link. Businesses switch away from ISDN for various reasons, including its lack of features and capabilities.  

Benefits of SIP Trunking

Knowing what SIP trunking is helps describe why it’s beneficial. Its features can reward businesses both financially and functionally, including in the following five ways.  

Snipping sheet of paper that says "Cost" with scissors

1. Significant Cost Savings

When it comes to SIP trunking, it's well known that its cost savings are substantial. Here are some of the ways that SIP trunking cuts costs:

  • Reduced phone lines to one entry point means reduced charges and less IT maintenance cost
  • Phone numbers, or DID (Direct Inward Dialing Number), cost less because it doesn't have the infrastructure costs of hardware and maintenance
  • You only pay for the lines needed or the minutes used, depending on your provider
  • Less maintenance, complexity, and administration—you no longer need to maintain IP infrastructure, and may even be able to eliminate your entire PBX (Private Branch Exchange, which switches lines on local calls)
  • Long distance service is typically significantly cheaper 

2. Eliminated Redundancy for a Unified Communications Solution

SIP trunking reduces the number of connections you need and is a great way to simplify into a single, IP-based network. If your company is spread across multiple locations, you'll no longer need to connect each location's PBX to ISDN.

3. Quick and Easy Scalability

SIP trunking is virtual, making it fast and easy to service or change the number of channels you need as your company grows, downsizes, or changes.

4. Flexibility

Because of SIP trunking's scalability, it's flexible to accommodate seasonality—where demands are greater or lesser at certain points of the year—by being able to rapidly change your telephony infrastructure to match. You can also easily change or keep outbound numbers no matter your location or if your company moves.

The number 24 circled with an arrow like a clock

5. Improved Phone Service Reliability

SIP trunking improves phone service reliability because it's redundant—it can improve your company's uptime during a failure or emergency by quickly rerouting service or forwarding the PBX to mobile phones. This can be done instantaneously, as opposed to up to 24 hours with other services, and without the expensive costs of call forwarding.  

Some are concerned about the security risk of SIP trunking, but when properly implemented, it is perfectly safe, if not even safer than before. This is especially true with the use of firewalls managed by your SIP provider.

Upgrade to SIP Trunking with LightBound

SIP trunking’s inherent benefits, including increased flexibility and cost savings, make it an easy choice for companies to make the switch from old technologies.

Is your company looking to buy or upgrade to a new phone system in the next 6 months? Talk to an expert to find out whether SIP trunking is right for your business.

LightBound is a SIP provider with a portfolio for all of your Unified Communications needs. We host and manage everything so you finally get a single, simplified source for local and long-distance service.

If you would like to learn more about transitioning to SIP trunking, contact us today!


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September 29, 2017 / by Dane Dittemore