SIP Trunking

SIP Trunking – 4 Important FAQs

In the fast-paced world of business communications, staying ahead is not just an advantage—it’s a necessity. One key player in this evolution is Session Initiation Protocol (SIP) trunking, a digital method transforming how we make and receive phone calls and engage in multimedia communication over the Internet.

What is SIP Trunking?

SIP Trunking

SIP trunking, in essence, is the digital highway for communication. It replaces traditional phone lines with virtual phone lines, known as SIP trunks, allowing businesses to connect with anyone globally over the internet. As countries phase out ISDN services, SIP trunks are emerging as the future-proof solution.

Benefits of SIP Trunking

Sip Trunking - Benefits

Cost Savings

Traditional phone lines can be pricey, but SIP trunking charges on a per-channel basis, offering flexibility and potential savings, especially for businesses with varying call volumes.


For businesses expanding across locations, SIP trunking provides a scalable solution. Calls between sites are often free, and bandwidth can be adjusted to accommodate the intended call volume.


SIP trunks boast reliability features like number failover and diverse routing, ensuring uninterrupted communication even in the face of network challenges.

Real-time Analytics and Cloud-based SIP trunking systems provide real-time analytics, empowering businesses with valuable data for informed decision-making and enhanced performance.

Centrally Managed Communication

By centralising phone calls, video conferencing, and messaging, SIP trunking simplifies management and improves overall communication efficiency.

Call Quality

SIP trunks ensure high-quality calls, backed by AI advancements that automatically enhance call quality and eliminate disruptions.


Dedicated connections and active monitoring for unusual behaviour make SIP trunks more secure than traditional phone systems.


Geographical constraints are a thing of the past with SIP trunks, offering local numbers anywhere and seamless relocation without losing phone numbers.

How Does SIP Trunking Work?

Sip Trunking - How does it work

SIP Channels

Digital counterparts to traditional phone lines, SIP channels enable simultaneous inward and outward calls, providing flexibility without physical rewiring.

SIP Trunks

Multiple SIP lines form SIP trunks, acting as virtual phone lines connecting businesses to Internet Telephony Service Providers (ITSPs) and facilitating communication with other networks.

SIP Protocol

The Session Initiation Protocol sets communication rules for making and ending data connections over the internet, supporting voice calls, video calls, and messaging services.

SIP Provider

SIP providers play a crucial role, running SIP connections through private branch exchanges (PBXs), offering services like SIP trunking and Internet Protocol PBX (IP PBX) solutions.

SIP vs. VoIP: Understanding the Difference

Sip Trunking & VoIP

While related, SIP and VoIP differ; VoIP is the broad term for all voice calls made via the internet, whereas SIP encompasses a broader range of technologies, supporting voice calls, video, conference calls, and messaging.

SIP Trunking vs. PRI Trunking: Making the Right Choice

Comparing SIP trunking to Primary Rate Interface (PRI) trunking emphasises the benefits of virtual connections over physical ones.

Choosing a SIP Trunking Service: Key Features to Consider

Real-time Data

Leading SIP providers offer real-time data access, providing transcription and machine-learning tools for actionable insights.

Security Measures

Robust security and authentication are crucial, with encryption ensuring secure phone calls and digital services.

Number Management

Seamless porting of existing numbers and centralised addition of new connections are essential features for a smooth transition.

Call Metrics

Providers offering comprehensive information about call completion percentages and voice quality enhance the transparency of your communication.


Customisation options and essential features like video conferencing and instant messaging ensure compatibility with your business needs.

In the dynamic landscape of business communications, SIP trunking stands as a reliable, scalable, and feature-rich solution. As you navigate through the intricacies of SIP, make informed decisions that align with your business goals and communication needs. Find out more about SIP vs VoIP from our strategic partner Gamma’s website here.

About Marlin Communications

Marlin Communications Ltd is a leading UK provider of business communications technology solutions across Voice, Video, Connectivity, Cyber Security and Business Mobiles.

We work with all the major solution providers including Microsoft, Zoom, GoTo, Mitel, Gamma, Yealink, Poly, SonicWall, O2 & Vodafone, to name just a few.

And with our expert team of Solution Consultants, Engineers and Support staff, we’re perfectly positioned to partner with you for the long-term and help your business connect, collaborate & grow.

Get the latest tech news & reviews – straight to your inbox

Sign up to receive exclusive business communications, tech content, new tech launches, tips, articles and more.