“SIP trunking” is one of those phrases that gets thrown around frequently under the assumption that everyone understands what it refers to. For those unfamiliar, though, it’s not exactly a self-explanatory term.
Often, explanations can include even more acronyms, which in turn must be broken down. Saying “it’s a digital alternative to ISDN lines that doesn’t require a PBX, and can be used for VoIP calling” is accurate, but can also leave people more confused than when they started.
So, let’s break it down as simply as possible: what is SIP trunking, how does it work, and what are its benefits?
What is SIP Trunking?
SIP, which stands for “session initiation protocol,” is basically the signal protocol that starts, maintains, and ends communication sessions, such as voice calls, video conferences, or even virtual reality meetings.
In other words, it’s what lets you make calls over the internet, rather than over a traditional phone line.
“Trunk” refers to the collected lines shared among a group of users.
Put them together, and you have SIP trunking: a collection of virtual lines used for sending voice data, videos, and messages over the internet.
SIP trunking is typically offered by Internet telephony service providers (ITSPs), and is a popular way to provide telephony and unified communications services to businesses.
To get more technical: SIP trunking connects a PBX (private branch exchange) to the outside world using end-to-end Voice over Internet Protocol (VoIP). It’s an easy way to transition to end-to-end IP telephony, which is a key part of unified communications.
Sounds a lot simpler that way, right? Now let’s get more into the details.
How Does SIP Trunking Work?
It all starts with the call, as the SIP protocol sends information from one address to the next. It just takes milliseconds to send the information back and forth, so all participants can talk normally with minimal delay.
When there are multiple SIP lines used for calls across an organization, that’s SIP trunking. While the number of SIP lines a trunk supports will vary based on the average number of calls the business handles, most businesses only need one SIP trunk for their entire communications ecosystem.
Companies can use desk phones, softphones, and mobile endpoints to connect to their SIP lines.
How is SIP different from VoIP?
If this all sounds like another way of describing VoIP, or “Voice over Internet Protocol,” you’re not entirely wrong. The big difference is in terms of what kind of data gets sent.
SIP is one of the tools that companies can use for VoIP calling, but while VoIP is primarily focused on voice, SIP lines can also be used for video, messaging, and so on. So while there is some overlap between the two, they’re not the same.
What are the Benefits of SIP Trunking?
Benefits of SIP trunking include:
- Lower costs: fewer lines mean companies are paying less compared to traditional phone lines. Plus, there’s a healthy amount of competition among SIP trunk providers, which keeps call charges low—some even offer unlimited calling.
- Scalability: Businesses can quickly and efficiently add numbers to their SIP lines, since the lines are all digital.
- More than just voice conversations: users can also send video and chat messages along with their voice calls.
- A unified platform: Calls, videos, and other communications are all handled in the same system, rather than needing a different solution for everything.
- Mobility: SIP trunks aren’t bound to a location, so you can move offices without having to change your number.
What to Look for in a SIP Trunk Solution
When purchasing a SIP trunking solution, you’ll want to keep several factors in mind, including:
- How many lines and how much bandwidth you’ll need: Understand your communication needs to ensure you have enough bandwidth for peak traffic volume, but without paying for more than you need.
- Security: Make sure your SIP trunking provider includes security features to defend against fraud and keep your data safe.
- Network options: Check if your SIP trunk provider runs their own network or offers a rebranded service from another provider. You’ll typically get the best level of features and functionality from companies with control over their own network.
- Reliability: Your SIP trunk provider should be able to offer a certain level of reliability for your calls.
- Flexibility: The best providers allow you to port your existing phone numbers into your new environment. Not all providers can manage this process for all regions, so consider this when making your choice.
- Features: Make sure that your SIP trunking provider can offer all the features you want, such as e911 support, caller ID, data sovereignty, and so on.
- Centralized vs decentralized trunks: Consider if your business will need a centralized solution, which directs calls to a single location, or decentralized, which gives each office its own SIP lines. This will typically vary based on your business’ size and number of locations.
Getting Started with SIP Trunking
Once you know your SIP trunking needs, it’s time to find a provider. Be sure to look for a solution that has the features you need at a price you’re willing to pay, and don’t forget to look at reviews and customer testimonials.
When you’ve chosen a provider, you can select a dedicated internet line. Some companies prefer to update their internet line before transitioning to ensure they have the speed and bandwidth to handle their calls. However, there are also providers that bundle their service options with a dedicated internet line to keep voice and data traffic separate.
When you’ve made your decision, your provider will be able to help you get set up and port over numbers, so your business can begin making SIP calls.
