Is a SIP Trunk Worth It? Yes, If You Like Flexibility.

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The beauty of a tree trunk is that it’s both solid and flexible; it can help a mighty oak thrive through even the harshest winds and changing weather conditions.

A Session Initiation Protocol (SIP) trunk has some things in common with its namesake.

A SIP trunk is a virtual communication hub that’s used to make voice and video calls online. Compared to traditional telephone technology, where trunks were bundles of phone lines shared between users, SIP trunks represent a collection of digital channels with the flexibility to carry out several different communication types at once.

The many benefits of SIP trunks include the ability to:

  • Keep your original phone numbers
  • Make calls from anywhere in the world
  • Pay only for what you need
  • Centralize management
  • Integrate multimedia communication
  • Support unified communications
  • Establish a global business communications presence

A SIP Trunk Upgrades Existing Equipment

Unlike traditional phone lines, which use a public branch exchange (PBX) that requires physical lines, a SIP trunk connects your private branch exchange to the internet. This translates to more efficient and flexible communication.

Some businesses still use traditional telephone systems, and this typically means they have a set number of lines connected to a public branch exchange—thus limiting the number of calls they could make and receive simultaneously.

SIP trunks cut through those physical constraints by using the internet to transmit voice signals instead of copper wires. In addition to transmitting voice signals, they also use SIP protocols to authenticate, assign numbers, and enable efficient multimedia exchange.

That means there’s theoretically no limit to the number of possible lines and calls that can happen simultaneously—all you need to do to scale your calling capacity is contact your SIP provider to upgrade your package.

Graphic to show how SIP trunking works from Nextiva.

SIP Trunk Advantages

As the technology progresses, there are more and more reasons why businesses would prefer a SIP-trunk-powered VoIP system over a landline.

Geographical Flexibility

The possibility for employees to work remotely can be critical for many modern businesses, yet old-school phone lines are tied to physical business infrastructure. SIP trunking allows employees to make video and audio calls from anywhere in the world with an internet connection. This flexibility extends to other features, like being able to forward calls to other numbers, extensions, and devices.

Cost Efficiency

With SIP trunks, you can say goodbye to long-distance calling costs and avoid paying for expensive phone carriers.

But the savings don’t stop there. Due to their virtual nature, SIP trunks can reduce hardware, maintenance, and infrastructure costs versus traditional telephone technology. Plus, their simple configuration and management interfaces make system administration simple, which can result in lower staffing costs as well.


Scaling traditional phone technology involves installing more cables and physical infrastructure. That can be cumbersome and costly.

But scaling with SIP trunks is simple and only limited by your available budget. Most SIP providers allow companies to pay only for the number of channels they need. This means you can adjust your communication infrastructure to meet your changing requirements without huge consequences if you need to change again. All it takes is contacting your provider.

Number Portability

Businesses often invest time and resources to establish their brand identity through specific phone numbers. Making sudden changes to those numbers can lead to confusion for customers and partners.

With traditional PSTN systems, it can be challenging (or even impossible) to keep existing phone numbers when switching providers or changing technology.

However, SIP trunks can make technology or provider transitions buttery smooth by allowing businesses to port existing numbers as they make the switch.

Enhanced Features

Traditional phone systems were built with one thing in mind—making voice calls.

SIP trunks go above and beyond mere voice calling to deliver a range of additional features, including:

  • Video calling
  • Voice-to-email messaging
  • Auto-attendants
  • Call routing and management

Considering the reduced costs of SIP trunks versus PSTN systems, this gives you much more bang for your buck. It can also lead to a more unified business communications setup that increases productivity.

Tradeoffs with a SIP Trunk

No technology is perfect. SIP trunks have drawbacks that might make some folks consider hanging on to their trusty copper line phone systems.

Reliance on Internet Connectivity

Traditional phone systems have a reputation for reliability because they can keep working during power outages. This ensures that communications don’t get interrupted due to emergencies.

SIP trunks need an internet connection to function. Thus, if the internet goes down or your power goes out, so does your ability to make calls. That means a SIP system might not be the best solution in areas prone to frequent internet or power outages.

Limited Technical Expertise

The initial setup of SIP trunks can be complex compared to maintaining a traditional phone system. Smaller businesses without dedicated IT support staff could lack the technical expertise to manage the setup and maintenance of a SIP system.

As a result, switching to a SIP trunk could require hiring additional resources or contracting external help.

Existing Infrastructure Investment

For businesses that are heavily invested in their current copper line infrastructure, the perceived cost and effort of switching to a SIP system could be a barrier.

The initial investment in SIP trunks can include updating and replacing equipment. Of course, this upfront money could also turn out to be well-spent, thanks to the long-term cost savings. You’ll need to weigh the short-term costs versus the anticipated benefits.

Bandwidth Requirements

SIP trunks need internet bandwidth to operate. Not having enough data transfer capacity available can lead to poor call quality, dropped calls, and other problems.

You might need to upgrade your internet infrastructure to meet the demands—which could lead to additional costs. Be sure to assess your current bandwidth situation and compare it against the requirements for SIP calling.

Migrating from PSTN to SIP Trunk

As some countries (including the United States) are planning to phase out PSTNs, many companies have already adopted SIP trunks.

In doing so, they’re reaping the benefits of greater flexibility, cost savings, and access to integrated communication features.

When making the switch, businesses can choose to enable their existing private branch exchange for SIP service or opt for a hosted solution managed by a service provider.

The decision between managing a SIP PBX internally or using a hosted solution depends on factors like your in-house technical expertise, infrastructure preferences, and the level of control you need.

Of course, working with a managed service provider gives you the advantage of outsourcing the technical aspects of SIP trunk management. This can be very useful for businesses without a dedicated IT department—but the trade-off is that you must rely on a contractor to maintain your critical communication resources, and that could be risky.

Getting a Good Deal on SIP Trunk Services

The pricing landscape for SIP trunk services can be complex. Vendors might break down costs differently, offering various plans based on the number of trunks, lines, or users. Some vendors provide a set number of monthly minutes, while others offer unlimited SIP trunks.

Understanding the term “unlimited SIP trunks” is crucial for this. While it might sound like you get unrestricted usage, these packages often come with fair usage policies. Vendors include these policies to ensure resources allocated to each user or organization within a shared service environment are used reasonably and responsibly. These policies can include bandwidth usage limits that prevent a single user from taking up more than their fair share of the data transfer capacity.

As a business owner, you should carefully assess your communication needs and choose a pricing plan that best aligns with your requirements.

The average monthly cost of a SIP trunk service can vary widely. The price often hinges on factors like the number of users, minutes required, and the features included.

Therefore, it’s critical to evaluate both the budget-friendly options and the premium services to understand what each offers. This will give you a good sense of what each end of the pricing spectrum provides so you can make an informed decision.

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