SIP trunking is one of those terms that comes up frequently in business phone conversations and is rarely explained clearly.
Here is what it actually is, how it differs from hosted VoIP, and how to know which one your business needs.
What SIP Trunking Is
SIP stands for Session Initiation Protocol. It is the technology that allows phone calls to travel over the internet instead of traditional copper phone lines.
A SIP trunk is essentially a virtual phone line. Instead of a physical cable connecting your phone system to the phone company, you have an internet-based connection that carries calls digitally.
The key thing: SIP trunking connects to your existing on-premise PBX system. You keep your hardware. You replace the physical phone lines connecting it to the carrier with internet-based connections.
How It Differs From Hosted VoIP
Hosted VoIP moves everything to the cloud. No on-premise hardware. The phone system itself lives on the provider's servers.
SIP trunking keeps your hardware on-site and replaces only the carrier connection. Your PBX stays in your server room. Your desk phones stay at their desks. You just swap out the lines for internet-based trunks.
The right choice depends on whether you want to keep your existing hardware investment or move to a fully cloud-based system.
When SIP Trunking Makes Sense
You have a relatively new on-premise PBX that is working well and you want to lower your carrier costs without replacing the whole system.
You have made a significant hardware investment that still has useful life in it.
Your IT team manages the on-premise system and prefers to keep infrastructure on-site.
In those situations, SIP trunking can reduce your carrier costs significantly without requiring a full system replacement.
When Hosted VoIP Makes More Sense
Your on-premise hardware is aging and approaching end of life.
You want to eliminate hardware maintenance entirely.
You have remote or mobile staff who need to be on the same system as the office.
You want features like voicemail-to-email, mobile apps, and advanced call routing without configuring them on aging on-premise hardware.
For most Montana small businesses today, hosted VoIP is the cleaner choice. SIP trunking makes sense for specific situations.
Cost Comparison
SIP trunks typically cost $15-$25 per channel per month. A channel handles one concurrent call. A business with 10 concurrent calls needs 10 channels.
Hosted VoIP typically costs $25-$45 per user per month and includes features that SIP trunking does not.
Depending on your current setup and usage, one or the other may be more cost-effective. It is worth running the numbers for your specific situation.