Insights & Resources4 min read

SIP Trunking vs VoIP - What's the Difference?

SIP Trunking and VoIP are related, but it's difficult to compare the two terms directly since there are some important differences between the two. Here's everything you need to know.

Brian Segal
Employee talking over SIP Trunking and VoIP
SIP vs VoIP is not a direct comparison, but understanding the nuances between the two will give you an advantage when building out your business’s communication solution. SIP and VoIP are heavily intertwined, but it’s important to note that they are not the same thing. Voice over IP (VoIP) does not require SIP in order to function while Session Initiation Protocol (SIP) is just one of the protocols that allows VoIP to function, and is the most widely used.

Sip Trunking vs. VoIP: What’s the Difference?

While you can’t directly compare SIP and VoIP, understanding each is the first step to choosing the best solution for your business. VoIP describes the method of delivering voice communications over the internet rather than using traditional phone lines. With the increasing popularity of broadband, VoIP has become a popular choice for businesses. The term VoIP includes any phone calls made using the internet.
VoIP is a group of technologies that allow for sending and receiving of voice messages over the internet, and SIP is one individual technology that supports VoIP.
SIP is one signaling protocol used to connect the participants in a VoIP call, and it’s the most common. So SIP requires VOIP but VOIP doesn’t require SIP.

How VoIP works with SIP

VoIP is a broad term referring to a group of technologies used for phone calls over the internet. SIP is one method of defining the messages sent between endpoints used for VoIP. SIP also supports video conferencing, messaging, and media transfer in addition to voice calls.
A SIP trunk acts as a virtual phone line and uses a packet switch network to connect calls. A SIP trunk then has SIP channels which act as individual calls. There is usually no limit to the number of SIP channels on a trunk, but that largely depends on your carrier.
SIP trunking delivers unified communications to users with a SIP enabled Private Branch Exchange (PBX). A PBX provides call management, voicemail, and other services. The SIP trunk connects to the public telephone network so the user no longer needs to rely on legacy telephone lines. This allows the business to select the IP-PBX hardware and software best suited for their needs and offers a flexibility that was previously unavailable with traditional phone lines.

VoIP Alternatives to SIP

While SIP is the most popular protocol it is not the only option, you can absolutely take advantage of VoIP to avoid PRI lines, even without SIP trunks. VoIP can be used alone with a hosted PBX to manage it or with other protocols that can be used instead of SIP such as H.323 and Media Gateway Control Protocol (MGCP) or proprietary protocols like Skype Protocol.

Pros and Cons of VoIP Only

Using VoIP alone is something that can be leveraged to great effect by many businesses. It is a low cost solution that is easy to implement and use without a long-term commitment.

Pros of VoIP Only

VoIP can be leveraged on it’s own as a simple, low cost solution for voice communication. The main benefits include:
  • Low cost to get started with continued savings and flat rate billing.
  • VoIP systems do not need an on-site installation and are easy to move.
  • Long-term contracts are not required for most VoIP providers.
Despite its ease of use, there are some limitations to be taken into consideration when using VoIP by itself.

Cons of VoIP Only

While using only VoIP certainly has its draws, it is often not a robust enough solution for many businesses. Somethings you may want to think about:
  • VoIP requires sufficient bandwidth to maintain call quality.
  • It lacks support for multimedia communications and is limited to only voice.
  • It lacks integration with commonly used third party applications.

Pros and Cons of SIP

While using VoIP alone has definite advantages, it can be enhanced by using SIP. You can increase both scalability and versatility with SIP, adding multimedia communications and more. While there are many reasons to leverage SIP, like using VoIP alone there are also drawbacks.

Pros of SIP Trunking

There are many advantages to using SIP for your business. While using VoIP alone has its advantages, the flexibility of SIP makes it a great choice for many companies.
  • Very scalable, SIP is not only limited to voice so you can expand into video, messaging and more.
  • Frequently has built-in integration with commonly used software for increased productivity.
  • Can be integrated with PRI lines for a combination phone system that best suits your business
Very flexible with pricing by allowing for additional features and lines as needed.

Cons of SIP Trunking

While the versatility and cost savings of SIP make it a great solution, like using VoIP alone it is not without its drawbacks.
  • Requires sufficient bandwidth to to maintain service quality.
  • Not all SIP providers offer the same features or quality of service, make sure you are choosing the right one for your business.
  • SIP can have issues with both quality and security if used on the public internet.

Which is Best for You?

If you are looking to switch to an internet based phone system understanding SIP vs VoIP will allow you to pick the best solution for your company. The comparison isn’t direct, but if you are deciding between a VoIP only solution and SIP trunking, the best place to start is to determine whether your business will be effectively serviced by voice only or if you need a more robust solution.
VoIP offers a cost effective, easy to implement voice only solution. This can be enhanced with SIP, offering more flexibility and a unified communication solution by offering multimedia communication in addition to voice. SIP is a great tool that can both cut costs and improve productivity for your business.
Looking to get started with VoIP? Learn more about VoIP and how it can help your business needs by talking to a Telnyx expert.
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