What Is SIP Trunking and How To Offer SIP Trunking Services

Communication drives your business forward. Client and vendor inquiries begin through phone conversations. Teams regularly meet in conference calls to examine information and brainstorm ideas. Establishing a clear communication process helps your employees increase their productivity. In order to build such a process, you need a Unified Communications and Collaboration platform, SIP trunking, DIDs and internet access.

What Is SIP Trunking and How To Offer SIP Trunking Services with VoipNow

On this blog, we’ve covered topics like Unified Communications and Collaboration, delved into the applications of VoIP technology and explored the mechanics of DIDs. Now, it’s time to dive into the world of SIP trunking.

We’ll start with insights into the meaning of SIP and the concept of SIP trunking. Next, we’ll guide you through the process of evaluating SIP trunking providers. Finally, we’ll show you how to use VoipNow & Hubgets to offer SIP trunking services.

What is SIP?

SIP stands for Session Initiation Protocol and it’s the signaling protocol for Voice over Internet Protocol (VoIP) system. Essentially, every call has two elements: the connection and the content. When two people want to communicate, a system needs to connect one party to another and allow them to speak. From there, the system needs to transfer packets of information (the messages people are saying) back and forth.

When done well, a communication system will be immediate and the connection will be clear. When done poorly, there will be delays in connecting two parties and lags in the transfer of information packets—leading to unwanted pauses or cut-outs during calls.

SIP streamlines the process of connecting multiple parties. The protocol allows people to communicate through voice or video calls. Consequently, it enables companies to provide employees with a phone service over the Internet instead of relying on traditional phone lines. This increases the level of security within the firm, especially for team members who work remotely or travel to meet with clients.

Opting for a SIP phone system can help companies step into the modern communication era. However, this is only the first part of the process. The next step is to establish a SIP trunking to streamline communication and optimize system management.

What is SIP trunking?

Even with a dedicated SIP phone system in place, companies can still experience communication issues. Large firms, in particular, need organizational processes in place to keep calls clear and prevent clutter. This is where SIP trunking services come into play.

SIP trunking enables the consolidation of various communication channels. You can think about it like this. If every call within your company is a branch, then the SIP trunk is what holds all of the branches together.

How does SIP trunking work?

SIP trunking architecture is made possible by IP-enabled PBX (Private Branch eXchange) technology. The PBX allows employees to make internal calls while also sharing a set of external lines to communicate with people outside of the company. It isn’t something you use as an alternative to VoIP or SIP, but rather an element that works as part of the greater ecosystem.

With a SIP Trunking in place, your employees could receive a call from anyone on the Internet. The information would be shared through secure packets that are delivered quickly and accurately from one person to the next. Trunking allows your company to receive several calls at once without clogging up phone lines or affecting your internet speed.

What did companies do before SIP trunking?

One of the best ways to understand the SIP trunking meaning is to look at forms of communication before these technology systems were popular.

The analog communications

The beginning of communications can be traced back to the use of smoke signals, drums, and pigeon messengers. However, the modern concept of communication networks began with the development of telegraphy in the early 19th century.

In the late 19th century, the first telephone was invented by Alexander Graham Bell. Next, the development of radio communication followed, which allowed for wireless transmission of audio and other signals.

In the late 19th century, the switchboard was invented. This new technology allowed multiple telephones to be connected to a central exchange. The Public Switched Telephone Network (PSTN) is a network of telephone lines, fiber optic cables, and other communication systems.

The PSTN allows users to make phone calls and send data across the globe. It required dedicated phones plugged into the wall. Communication traveled through a series of phone lines. Moreover, companies were limited by the number of incoming and outgoing calls they could make at once.

The beginning of digital transmission

The first generation of digital transmission systems, known as E1 (Europe) or T1 (North America), emerged in the early 1960s. These systems transmitted digitized voice and data signals over traditional telephone networks.

E1 was introduced in Europe in 1963, while T1 was deployed in North America in 1964. Both systems used time-division multiplexing (TDM) to transmit multiple signals simultaneously over a single communication channel. They divided the bandwidth into equal time slots. This allowed multiple channels to share the same physical medium.

The primary application of E1/T1 was to transport large numbers of voice circuits between telephone exchanges. Each E1/T1 signal could carry up to 30 simultaneous voice conversations. This significantly increased network capacity compared to analog systems. Additionally, these systems provided better call quality and greater reliability than earlier analog technologies.

However, E1/T1 had several limitations:

  • Limited bandwidth
  • Inflexibility
  • High latency
  • Costly infrastructure

As technology advanced, newer digital transmission systems replaced E1/T1 in many parts of the world. These systems offer higher speeds, lower latency, and greater flexibility. Thus they are better suited for today’s diverse communication demands.

Modern communications

With VoIP systems and SIP trunking, companies can bundle their communications for easy scaling. It doesn’t matter whether one person is making a call or 100 employees are talking with clients and vendors at once, the quality remains the same.

Depending on the provider and the options you choose, your company can have a higher number of channels available within each SIP trunk. Thus, you only need one SIP trunk to operate your business.

SIP trunking advantages

SIP trunking systems offer a wide range benefits for businesses. Here are some of the key communication functions and advantages.

Voice communication

SIP trunks allow businesses to make and receive voice calls over the internet. This includes local, long-distance, and international calls. And for long-distance communication it provides important cost savings.

Video calls

SIP trunking supports video calls, enabling face-to-face communication with colleagues, clients, and partners. Therefore, it’s especially useful for remote work and global collaboration.

Unified Communications

SIP trunks can integrate with UC platforms. For example, VoipNow & Hubgets bring together voice, video, and instant messaging in one interface. Therefore, collaboration and productivity greatly improve.


SIP trunking is highly scalable. As your business grows, you can easily add or remove trunks to accommodate your changing communication needs.


SIP trunks offer flexibility by allowing businesses to choose the number of channels (trunks) they need.

Disaster recovery

You can configure SIP trunks to make automatic failover to backup locations. In case of network or system failures, this ensures uninterrupted communication.

Cost savings

SIP trunks are typically more cost-effective than traditional telephone lines. They eliminate the need for physical phone lines and reduce long-distance call expenses.

Local and toll-free numbers

SIP trunking enables businesses to acquire local and toll-free phone numbers in various regions. In turn, this makes it easier to establish a presence in different locations.

Number portability

SIP trunks often allow number portability. For instance, you can keep your existing phone numbers when switching providers or moving locations.

Quality of service (QoS)

SIP trunking services can provide QoS features to prioritize voice and video traffic. This results in clear and high-quality calls.

International expansion

For businesses looking to expand internationally, SIP trunks can provide access to local numbers in foreign markets. Thus serving customers in different regions becomes easier.


SIP trunking providers typically offer security features to protect against fraud and unauthorized access. If you use a state-of-the-art platform like VoipNow & Hubgets, you enjoy even more protection. Set limits on the number of concurrent calls and telephony usage, use media encryption, and watch the available balance notifications.

Advanced features

Many communications platforms with SIP trunking services offer advanced call management features: call routing and fallback, voicemail-to-email, call recording, and call analytics.

Analytics and reporting

SIP trunking systems often include analytics and reporting tools. Such tools help you track call metrics and analyze communication trends.

Clearly, a SIP trunking-based system offers a plethora of compelling benefits and advantages.

SIP trunk vs. VoIP: What’s the difference?

As you build out your communications protocols, you might notice that SIP and VoIP are used interchangeably. These terms do not mean the same thing. SIP is a protocol that makes VoIP possible.

If you have a VoIP system that uses SIP trunking, then your system is SIP-based. However, not all VoIP is SIP. So make sure you have a clear understanding of how your system works when you use these terms.

Once you understand this relationship, you can move forward with SIP trunking with VoipNow & Hubgets. More than 15,000 service providers use the platform worldwide. It delivers PBX functionality, voice, video, presence, instant messaging, conferencing, faxing, and contact center communications from one system.

Companies can offer SIP trunking as an extension of their VoIP services. You can connect a PBX to an extension in VoipNow & Hubgets and set a limit on the number of concurrent calls made within your organization.

How to offer SIP trunking services with VoipNow & Hubgets

If you are a service provider, read this detailed guide on setting up SIP trunking services. You can use this tutorial if you already use these services and want to improve your communications with SIP trunking. Here are a few highlights for the SIP trunk configuration process.

  • Review your extensions. Look for the Provisioning and SIP preferences within your available extensions. Select the Enable for SIP trunking service option.
  • Enter the IP address of the PBX that connects to your VoipNow server. You should be able to find this in the Phone does not register, is located on IP field.
  • Under the Roles and Phone Numbers section, you will find a field called Maximum public concurrent calls. This allows you to restrict the number of concurrent calls that go through your system. You can change this limit depending on your needs each day.
  • Consider the different levels within your organization. You can set limits based on the user, department, organization, or server. Consider how different calls are made and which limits are useful.

Billing for SIP trunking is based on your limit of concurrent calls. This is why it is important to evaluate your concurrent call needs. Furthermore, the platform offers service providers the capability of overselling.

Evaluate SIP trunking providers for your business

For over two decades, we’ve collaborated with service providers and enterprises worldwide. We understand the significance of assessing SIP trunking providers to identify the ideal fit for your business. Thus we devised this checklist to assist you in navigating your choices before making any commitment.

  1. Test the user portal. Make sure there is an easy-to-use system that your team can navigate organically. Your SIP providers should also have tutorials to help you use the system and a customer support line if you need help.
  2. Review the pricing model. Find a SIP trunking provider that scales to your needs. Look for a model where you only pay for the resources that you use.
  3. See which add-ons are offered. Avoid bulky packages where you are stuck with several unnecessary features when you only need a few.
  4. Ask which size clients the SIP provider works with. If you are the smallest client, you might not get the attention you deserve. If you are the largest, the company might not be able to handle your needs.
  5. Verify whether SIP failover is offered. SIP failover helps ensure high availability of the communication system by providing automatic backup and redundancy for SIP trunks. It becomes useful in the event of a disaster or major outage. Then, SIP failover can help you quickly restore phone service by automatically switching to a standby trunk.
  6. Evaluate the implementation process. How long will it take to add the new trunks to your communications platform?
  7. Review the contract of your old SIP trunking provider. How soon can you cancel the contract if you no longer want to work with that company? What is the process to switch to another provider?

Many companies can’t afford for their communication systems to go down for more than a few minutes, much less several hours. If you need to switch SIP trunking providers, you need to make sure there is a smooth transition from one to another. Your employees must be able to make calls uninterrupted.

Invest in SIP trunking

If your business runs on clear communication, make sure your team members can easily connect with each other and with your clients.

A platform like VoipNow & Hubgets serves as a versatile and cost-effective solution for modern business communication. It offers an array of features and benefits that can enhance productivity, reduce costs, and adapt to a company’s evolving needs.

With such a platform in place, you can spend less time managing your phones and more time using them. Learn more about VoipNow & Hubgets and how to use SIP trunking with it.

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