What Are the Difference Between SIP Trunking and VoIP?

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Comparing SIP Trunking and VoIP

If you’ve ever wondered what is the difference between SIP trunking and VoIP, you’re in the right place. These technologies are essential for modern business communication, but they serve different purposes.

Here’s the quick answer:
VoIP (Voice over Internet Protocol): Technology for making voice calls over the internet.
SIP Trunking (Session Initiation Protocol): Protocol that enables not just voice, but also video, messaging, and other multimedia sessions over the internet.

In other words, VoIP is “what” enables internet calling, and SIP is “how” it’s managed and expanded to more than just voice calls.

Effective communication is key for any business, especially as technology evolves. Modern businesses need flexible, cost-efficient solutions. SIP trunking and VoIP provide the backbone for digital communication, transforming traditional phone systems and enabling seamless connections across various channels.

Difference between SIP and VoIP infographic - what is the difference between sip trunking and voip infographic cause_effect_text

For businesses looking to streamline their operations, understanding these technologies can make a big difference. You can upgrade to a more versatile and cost-effective system, meeting the needs of today’s world.

Ready to dive in deeper? Let’s explore the technicalities next.

What is VoIP?

Voice over Internet Protocol (VoIP) is a technology that allows you to make voice calls using a broadband internet connection instead of a regular phone line. VoIP converts your voice into digital data packets and transmits them over the internet.

Hosted VoIP vs. Non-hosted VoIP

Hosted VoIP and non-hosted VoIP are two different ways to set up VoIP systems for businesses.

Hosted VoIP is like renting a fully-furnished office. Your VoIP provider handles everything—servers, software, and maintenance. This makes it a cost-effective choice, especially for small businesses. You don’t need to buy or maintain any hardware. Just plug in your internet-connected devices (like laptops, smartphones, or VoIP handsets) and you’re good to go.

On the other hand, non-hosted VoIP is like owning and managing your own office. You purchase and maintain all the equipment yourself. This includes routers, PBX (Private Branch Exchange) systems, servers, and other hardware. While the initial setup and maintenance can be costly, non-hosted VoIP offers better customization and data security. It’s ideal for larger businesses with the budget and space to manage their own telephony infrastructure.

How VoIP Works

VoIP uses packet-switching technology to transmit audio signals. Here’s a simple breakdown:

  1. Voice Signal Conversion: When you speak into a VoIP phone, your voice is converted into digital data packets.
  2. Data Transmission: These packets are sent over the internet to the recipient.
  3. Signal Reversion: On the other end, the packets are converted back into audio signals so the recipient can hear your voice.

Hosted VoIP

In a hosted VoIP setup, you outsource your VoIP infrastructure to a third-party provider. This means they handle everything from software updates to server maintenance. Hosted VoIP is a great option for small to medium-sized businesses because it reduces upfront costs and eliminates the need for in-house IT staff to manage the system.

– Lower initial costs
– Minimal maintenance
– Easy to scale

– Less control over customization
– Ongoing subscription fees

Non-hosted VoIP

With non-hosted VoIP, you manage your own telephony system. This usually involves setting up a PBX system to route calls within your organization. Non-hosted VoIP is often preferred by larger businesses that need more control over their communication systems.

– Greater control and customization
– Enhanced data security
– Potential long-term cost savings

– Higher initial setup costs
– Requires in-house IT expertise
– Regular maintenance is needed

Example: A large corporation with multiple departments might opt for a non-hosted VoIP system. This allows them to customize their PBX to route calls efficiently and maintain high security standards.

By understanding the differences between hosted and non-hosted VoIP, you can choose the best option for your business needs. Whether you prioritize cost, control, or scalability, there’s a VoIP solution that fits.

What is SIP?

How SIP Works

Session Initiation Protocol (SIP) is a communication protocol used to initiate, maintain, and terminate multimedia sessions. These sessions can include voice, video, messaging, and fax. SIP is a critical part of modern VoIP systems.

How does SIP work? It all starts with data packets. SIP sends these packets between two endpoints, known as SIP addresses.

Endpoints: These are the devices involved in the communication, like phones, tablets, or computers.

SIP addresses: Think of these as digital addresses that identify each endpoint in the network.

When Person 1 wants to start a call, SIP sends an “invite” message to the endpoint of Person 2. This invite has all the necessary details to set up the call (like the codecs to use).

The invite travels through proxy servers, which act like digital switchboard operators. These servers route the invite to the correct endpoint. Once Person 2 answers, the call is established, and data packets start flowing between the two endpoints.

Proxy servers are essential for managing and routing these calls efficiently. They ensure the invite reaches its destination and handle other tasks like authentication and call forwarding.

During the call, SIP manages the data packets that carry the voice, video, or other media. It ensures that these packets are sent and received in the correct order, providing a smooth communication experience.

SIP response codes are used to communicate the status of the invite and the call. For example, a “200 OK” response means the call has been successfully established, while a “404 Not Found” response indicates that the SIP address is incorrect or unavailable.

Using SIP, businesses can integrate various forms of communication into a single system, making it easier to manage and more cost-effective. SIP’s flexibility and scalability make it a powerful tool for modern business communication.

Now that we understand SIP, let’s explore SIP trunking, which leverages SIP for even more advanced communication capabilities.

What is SIP Trunking?

SIP trunking is a method that allows businesses to make and receive phone calls over the internet. It’s like having a virtual phone line that connects your internal phone system to the outside world.

How SIP Trunking Works

Virtual Phone Line

Think of a SIP trunk as a virtual highway for your phone calls. Instead of using traditional phone lines, SIP trunking uses the internet to connect your business phone system to the public telephone network.

Multiple Channels

A SIP trunk can support multiple channels. Each channel is like a lane on a highway, capable of carrying one call at a time. This means you can handle many calls simultaneously without needing multiple physical lines. You can also add multiple SIP trunks to support even more channels.


One of the biggest advantages of SIP trunking is its scalability. You can easily add or remove channels based on your business needs. This flexibility helps you manage costs and ensures you always have the right number of channels.

Cost Efficiency

SIP trunking can save you money in several ways. First, it reduces the need for expensive physical phone lines. Second, it often comes with lower call rates, especially for long-distance and international calls. Finally, it simplifies your infrastructure, which can lower maintenance costs.

Channels and Outbound Calls

When you make an outbound call using SIP trunking, your device initiates a session that occupies one channel. This channel connects your call to the public internet or your telecom carrier’s network, sending a signal to complete the call. If another person makes a call at the same time, a different channel is used, but both calls go through the same SIP trunk.

Public Internet and Telecom Carrier

SIP trunking uses the public internet to connect your calls. This connection goes through your telecom carrier, which acts as a bridge between your internal phone system and the public telephone network. This setup allows you to make and receive calls from anywhere in the world.

By using SIP trunking, businesses can streamline their communication systems, reduce costs, and easily scale their operations. This makes it a powerful tool for modern business communication.

What is the Difference Between SIP Trunking and VoIP?

SIP Trunking vs. VoIP: Pros and Cons

When comparing SIP trunking and VoIP, understand that they are not the same thing. VoIP (Voice over Internet Protocol) is an umbrella term for any voice communication over the internet, while SIP (Session Initiation Protocol) is a specific protocol used within VoIP to enable multimedia sessions.

SIP Protocol: SIP is a protocol that manages the initiation, maintenance, and termination of real-time sessions. These sessions can include voice, video, and messaging. This makes SIP a more versatile option compared to basic VoIP, which typically only handles voice communication.

VoIP Umbrella Term: VoIP encompasses various technologies and protocols, including SIP. It’s the method by which voice calls are transmitted over the internet. VoIP can work with different protocols, but SIP is one of the most common due to its flexibility and multimedia support.

Multimedia Support: One of the main advantages of SIP over traditional VoIP is its support for multimedia. SIP can handle video calls, instant messaging, and even faxing, providing a more comprehensive communication solution.

Scalability: SIP trunking offers excellent scalability. You can add or remove channels as needed, making it easy to scale your communications up or down based on your business needs. VoIP systems can also scale, but they may require more significant adjustments to the underlying infrastructure.

Cost: Both SIP trunking and VoIP can be cost-effective compared to traditional phone systems. However, SIP trunking often provides better long-term savings due to its flexibility and efficiency. You only pay for the channels you need, reducing unnecessary expenses.

Bandwidth: Both technologies require sufficient bandwidth to maintain call quality. Poor internet connections can lead to dropped calls and poor audio quality. It’s crucial to ensure your internet service can handle the additional load.

Integration: SIP trunking excels in integration capabilities. It can easily integrate with various third-party apps and software, enhancing your communication system’s functionality. VoIP can also integrate with other systems, but SIP’s flexibility often makes it the better choice for complex setups.

Security: Security can be a concern with any internet-based communication system. SIP trunking can offer robust security features, such as encryption and authentication, to protect your data. VoIP systems also need strong security measures, but the level of security can vary based on the provider and setup.

Flexibility: SIP trunking provides unmatched flexibility. It can work with existing PBX systems, allowing for a hybrid setup that combines traditional and modern communication methods. VoIP systems are also flexible but may require more changes to your existing infrastructure.

In summary, while VoIP is a broad term that includes various technologies for internet-based voice communication, SIP trunking is a specific protocol that enhances VoIP by adding multimedia support and greater flexibility. Understanding the difference between SIP trunking and VoIP can help you choose the best solution for your business needs.

SIP Phones vs. VoIP Phones

SIP-Enabled Devices

SIP phones are devices that support the Session Initiation Protocol, enabling them to handle not just voice calls, but also video, messaging, and other multimedia communications. This makes them highly versatile and suitable for modern business needs.

VoIP phones, on the other hand, focus primarily on voice communication over the internet. While they can be part of a SIP system, not all VoIP phones are SIP-enabled.

Multimedia Functionality

One of the key differences between SIP phones and VoIP phones is their multimedia functionality. SIP phones can manage various types of media, including:

  • Voice calls
  • Video calls
  • Instant messaging
  • Faxing

This multimedia support is crucial for businesses that require more than just voice communication. For example, a company that frequently engages in video conferences would benefit significantly from SIP phones.

Hardware Requirements

When it comes to hardware, SIP phones and VoIP phones have some distinct differences:

  • SIP Phones: These can operate independently of a computer. They only need an internet connection and can be used right out of the box. This makes them easier to deploy in a variety of settings.
  • VoIP Phones: These often require a computer connection to function. They rely on the computer’s software to handle the voice calls, which can be limiting in some situations.

Choosing the Right Phone for Your Business

When deciding between SIP phones and VoIP phones, consider the following factors:

  • Multimedia Needs: If your business requires video calls, messaging, and other multimedia features, SIP phones are the better choice.
  • Hardware and Setup: SIP phones are simpler to set up and don’t need to be connected to a computer, making them more flexible.
  • Cost: While SIP phones may have a higher upfront cost, their added functionalities and ease of use can offer better value in the long run.

Next, we will answer some frequently asked questions about SIP trunking and VoIP to clear up any remaining doubts you might have.

Frequently Asked Questions about SIP Trunking and VoIP

Do I need a SIP trunk for VoIP?

No, you don’t always need a SIP trunk for VoIP. VoIP is a broad term that refers to any voice communication over the internet. SIP trunking is one way to implement VoIP, but it’s not the only way.

For example, you can use hosted VoIP services that manage everything for you without needing SIP trunks. These services are great for small businesses that don’t want to deal with the technical setup.

However, SIP trunking offers more control and scalability. If your business needs advanced features like video calls, messaging, and faxing, SIP trunking is the way to go. It integrates multiple communication forms into one system, making it a powerful tool for growing businesses.

What is the difference between IP trunk and SIP trunk?

An IP trunk and a SIP trunk are often confused, but they have distinct roles.

  • IP Trunk: This is a broader term that refers to any trunk (or line) that uses Internet Protocol to carry calls. IP trunks can use various protocols, not just SIP, to connect calls over a private network.
  • SIP Trunk: This is a specific type of IP trunk that uses the SIP protocol. It connects your PBX to the public internet and telecom carriers, allowing you to make and receive calls over the internet.

All SIP trunks are IP trunks, but not all IP trunks are SIP trunks. SIP trunks are popular because they support multimedia communication and are very scalable.

Is SIP more secure than VoIP?

Security is a major concern for any business communication system. So, is SIP more secure than VoIP?

The answer is nuanced. SIP itself isn’t inherently secure. However, you can implement SIP trunk encryption to secure your communications. This encryption protects your data from eavesdropping and unauthorized access.

On the other hand, VoIP security depends on the protocols in use. VoIP can be secure if it employs strong encryption and authentication methods. However, if it uses older or less secure protocols, it may be vulnerable to attacks.

In summary, both SIP and VoIP can be secure if implemented correctly. For the best security, ensure that your provider uses encryption and robust authentication methods.

For more on securing your SIP trunk, check out this article on SIP trunk encryption.


Choosing between SIP trunking and VoIP can be a game-changer for your business communication strategy. Understanding what is the difference between SIP trunking and VoIP helps you make informed decisions that align with your business needs.

VoIP is an umbrella term for any voice communication over the internet. It’s a great solution for basic voice calls, especially if you already have a robust internet connection. On the other hand, SIP trunking goes a step further. It not only supports voice calls but also integrates video, messaging, and other multimedia services. This makes SIP trunking a more versatile and scalable option for growing businesses.

Key Takeaways:

  • VoIP is excellent for basic voice communication over the internet.
  • SIP Trunking supports multimedia sessions, making it more versatile.
  • SIP trunking can be more cost-effective and scalable in the long run.

When deciding between the two, consider your current communication needs and future growth. If you’re looking for a simple, voice-only solution, VoIP might be sufficient. However, if your business requires a more comprehensive communication system that includes video conferencing, messaging, and other features, SIP trunking is the way to go.

At SIP.US, we offer tailored SIP trunking solutions to fit your business needs. Our platform is designed to simplify the selling and maintaining of your customer base, making it easier for you to focus on what you do best—running your business. Get started today.

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