Understanding the Difference Between a SIP Line and SIP Trunk
Before explaining the differences between SIP line and SIP trunk, it's important to start by talking a bit about the history of phone service. Internet phones are a newer concept. Prior to the turn of the 21st century, they weren't part of any standard business toolkit, as the Internet simply didn't have the means to make this type of phone a viable option.
Nowadays, however, Internet-powered phone service is enormously popular. If terms like "line" and "trunk" sound a little silly now, it's likely because these terms derive from earlier in phone history. But we still use them today because of convenience.
Here's what each of these terms means:
- SIP (Session Initiation Protocol): SIP is a sort of "language" used to communicate and package the data of which Internet-based phone service is made. It happens to be one of the most popular languages for this purpose.
- VoIP (Voice over Internet Protocol): VoIP is the name given to Internet phone service, allowing subscribers to call the phone numbers of other VoIP subscribers, as well as legacy phone system users.
- POTS (Plain Old Telephone Service): POTS refers to the original, copper-wire-based phone system of yesteryear.
- SIP line: Once upon a time, phone connections were called lines because, well, they were lines extended between two points. Now, a SIP line is somewhat more abstract, as there's not necessarily a literal line. SIP lines live on the Internet.
- SIP trunk: A trunk is a bundle or multiple phone lines working together. With SIP, this is more of a way of imagining VoIP connections, since the Internet itself could be called a single connection linking together all VoIP users.
SIP Line Vs. SIP Trunk
In practice, there's not much of a difference. The two terms both essentially refer to your VoIP connection, so there isn't a much literal distinction between them. That said, there are real differences.
These differences could be more critical when we talk about individual links (e.g., a SIP line between you and any given other phone subscriber). Or, SIP trunking service connecting you into the phone network itself — the public phone network, allowing you to make and receive phone calls.
These two terms also become useful when we try to visualize how much capacity a single VoIP subscriber needs to make concurrent phone calls. A call between two parties is carried by a line, and a trunk carries or represents multiple lines. So, if you need capacity for 100 simultaneous calls, that's a SIP trunk that holds 100 lines.
Understanding VoIP Capacity
SIP lines and trunks, then, are ways to understand VoIP service capacity instead of talking about bandwidth. These terms allow us to think of how many calls a connection can actually support and whether a certain bandwidth is really enough.
To build your capacity, you may need a different VoIP service, albeit a different vendor or service package. From there, you might also need a different Internet connection or equipment. If you're not sure what you need, talking with your VoIP vendor about your service options is a good idea. They'll let you know what they offer and how to upgrade if you need more capacity.
One significant advantage of VoIP service is it's generally easy to increase your call capacity or scale your capacity to your needs. In other words, you aren't stuck with what you currently have. You can even choose a service that allows you to scale your service in real time as your call volume fluctuates with busier times and seasons.
Choosing the Right SIP Trunking Service
Having the right technology, of course, can make or break your business. You'll need to do your own research to find the best vendor for your business needs and goals. As you review your options, document your current needs as well as any you anticipate. Then, ask prospective vendors about their experience meeting similar demands from other customers. Compare the plans they recommend, and consider how each recommendation may serve your organization and your customers.
Choosing the right technology is crucial to a growing business. Take the uncertainty out of the equation by choosing a SIP technology provider that can scale to meet your business' needs, whatever they may be at any given time. Call 1-866-879-8647 or fill out our online form to request a no-obligation quote from an 8x8 Product Specialist.