SIP vs. VoIP: Related, but not the same. Though these two terms are sometimes used interchangeably, there’s more nuance to their definitions than some might realize. To understand the difference between SIP and VoIP, let’s start with the basics.
What’s VoIP?
VoIP (Voice over Internet Protocol) is the technology that allows us to make phone calls over the internet instead of traditional phone lines.
Due to easy availability of high-speed internet and the gradual phase-out of traditional landlines (i.e. Public Switched Telephone Network (PSTN)), VoIP is rapidly gaining popularity as a modern, cost-effective, and flexible telephony solution for businesses to stay connected.
What’s SIP Trunking?
Think of SIP (Session Initiation Protocol) as a traffic controller for your VoIP calls. It's the protocol that sets up and manages your multimedia communication such as voice, video, and even text conversations. In simple terms, SIP is the foundation upon which multimedia VoIP is built.
SIP enables SIP Trunking, which is a specific method of delivering VoIP service. Essentially a virtual phone line, a SIP trunk uses the internet to connect your on-premise phone system (PBX) to the cloud rather than directly to the PSTN.
The bottom line:
It’s inaccurate to think of the two as competing solutions. Rather, one (SIP) builds on the other (VoIP).
Key elements of SIP Trunking vs. VoIP
Now that we’ve established the basics, let’s explore the major elements that define VoIP and SIP Trunking.
VoIP (Voice over Internet Protocol)
- Broad concept: A way to make phone calls over the internet rather than via traditional phone lines.
- Technology: Enables the digital transmission of voice communications.
- Flexibility: Can be implemented in several ways such as via SIP Trunking, cloud-based PBX, and softphones.
- Features: On its own, VoIP can only be used for voice calls over the internet. With SIP, VoIP systems can support voice, video, text messaging, and other multimedia communications.
SIP Trunking
- Specific method: An internet protocol to deliver VoIP service by connecting an on-premise PBX to the Public Switched Telephone Network (PSTN) via the internet.
- Virtual phone lines: A SIP trunk replaces traditional phone lines with digital channels.
- Scalability: Businesses can easily add or remove phone lines as needed.
- Infrastructure: SIP Trunking requires an existing on-premise PBX system.
A pro-con list for SIP Trunking and VoIP
Even though the two aren’t competing solutions, it might help to weigh the pros and cons of each to better understand how they work.
SIP Trunking
Pros |
Cons |
| Cost savings: Lowers phone bills by eliminating traditional phone lines. | Requires on-premise PBX: Not suitable for businesses without a PBX system. |
| Scalability: Easy to add or remove phone lines as your business grows. | Potential upfront investment: New equipment or software might be required. |
| Features: Includes call forwarding, voicemail, and video conferencing. | Technical expertise: Might be needed for setup and maintenance. |
| Improved call quality: Known for better call quality than traditional lines. |
VoIP
Pros |
Cons |
| Cost savings: More cost-effective than traditional phone lines, especially for long-distance calls. | Dependent on internet quality: Call quality can be affected by internet connection issues. |
| Scalability: Easy to scale to meet changing business needs, often with cloud-based solutions. | May require new equipment: New phones or adapters might be needed, depending on the chosen VoIP solution. |
| Flexibility: Works with a wide range of devices including computers, smartphones, and IP phones. | Potential security concerns: Security measures need to be implemented to safeguard data privacy. |
| Features: Ideal for business on the go with features such as auto-attendant, call forwarding, instant text response, and more. |
SIP Trunking vs. VoIP: Which works best for your business?
Now that we've explored the strengths and weaknesses of each, which should you go for? First, answer these three questions:
- Voice or multimedia? Will a VoIP phone system suffice or do you need a multimedia communication solution that includes voice, video, and text? If the latter, you’ll definitely need SIP Trunking.
- Do you have a PBX system in your building? If yes, SIP Trunking is the answer. If no, VoIP might be the easier option.
- Do you have a reliable internet connection OR a remote workforce? If you answered yes to either, then VoIP is the clear choice, as VoIP systems run entirely online.
Suitability by business size
Business size |
SIP Trunking |
VoIP |
| Small business | A good fit if you already have an on-premise PBX system. Cost-effective and flexible. | Particularly attractive for small businesses due to low upfront costs, scalability, and feature-rich packages. |
| Medium-sized business | A great option if you have an existing PBX and are looking to expand your phone system. | A popular choice for medium-sized businesses experiencing growth due to flexibility and scalability. |
| Large enterprise | Ideal for large enterprises with established on-premise PBX systems, especially for migration to VoIP. | Cloud-based VoIP solutions are particularly attractive for large-scale deployment due to their capability for handling high call volumes and remote workforces. |
Ultimately, the best choice for you depends on your specific business requirements, IT infrastructure, budget, and workforce (on-site or remote).
The business essentials you need to sound big and grow bigger
To recap, SIP Trunking is the right choice if your business has an existing PBX system, especially if you’re looking to migrate to a VoIP system down the line.
On the other hand, if your business doesn’t have a PBX system, and you need a cost-effective cloud-based telephony system that supports a remote workforce, then VoIP is clearly the way to go.
As an entrepreneur or small business owner, you might appreciate a feature-packed virtual phone solution that provides all the communication essentials your business needs to sound big and grow bigger.
With Grasshopper, you’ll get a full virtual phone system with VoIP, voicemail transcription, call forwarding, and lots more. Not only is it affordable, but it comes with 24/7 support to run your business on the go.