What Is SIP Termination? A Guide for Resellers and Telecom Businesses

Introduction

SIP termination is the process of routing outgoing calls from a VoIP or SIP-enabled network to the Public Switched Telephone Network (PSTN) or another telephony system. In essence, it’s the “exit door” that enables calls originating on the internet to reach traditional phone lines.

Particularly for telecom service providers and platforms offering voice at scale, SIP termination is critical to global voice communications, as it allows users to make calls to regular phone numbers (including landlines and mobile phones), using their internet-based communication systems.

SIP Termination Explained

[Image source: Telecom R & D]

SIP termination enables the delivery of outbound calls via SIP, or Session Initiation Protocol, which is a signaling protocol used for initiating, maintaining, and terminating real-time sessions, including voice and video calls, over Internet Protocol (IP) networks. It is often facilitated by SIP trunks, which are virtual connections that carry voice and other media over IP.

So, SIP termination is the process of sending calls initiated through a SIP trunk to its final destination. This is in contrast to SIP origination, which is the reception and handling of calls from traditional phone networks like the Public Switch Telephone Network (PSTN) or other SIP-enabled devices.

SIP termination begins with call initiation, when a user initiates a call from a VoIP phone or application. This call is then converted into SIP packets and routed through the VoIP (Voice over Internet Protocol) network.

During the routing and termination stages of the process, the provider’s network routes the call to the appropriate gateway, which then converts the call to the PSTN or other network for delivery to the recipient. Call completion occurs when the call reaches the recipient’s phone.

[Image source: Telecom R & D]

In a VoIP architecture, SIP termination implements the signaling process needed to disconnect a call from the VoIP side, and hand it off to the destination network. SIP trunks, which are virtual connections that carry voice and other media over IP, assist in this process.

Border elements such as Session Border Controllers (SBC) in the network manage the traffic flow between the internal VoIP network and the external PSTN or other networks, ensuring proper call routing and termination.

When terminating a call to the PSTN, intermediary technologies like an IP-PSTN bridge assist in translating the SIP messages into the appropriate signaling protocols used by the public network (like ISUP or SS7).

The IP PBX (Internet Protocol Private Branch Exchange) is the main control center for any VoIP implementation. It handles the control or setup of calls and the routing of network traffic flows.

Across the network, media gateways perform various functions including analog to digital conversions, echo cancellation, and silence suppression. Some gateways provide the ability to connect to the PSTN for completing calls, while others provide analog interfaces to VoIP networks.

[Image source: Telecom R & D]

Who Needs SIP Termination Services?

Organizations that rely on VoIP or need to connect to the traditional PSTN benefit from SIP termination services. This includes businesses of all sizes, that require reliable and cost-effective voice communication.

Telecom resellers and VoIP startups can rely on SIP termination for efficient call routing, handling high call volumes, and ensuring clear communication with customers and stakeholders. When implemented with security measures like encryption and firewalls, SIP termination can assure clients of a reliable and secure communication channel. SIP termination is also flexible, and can easily scale with changing conditions and business needs

SIP termination reduces the chances of call drops or connectivity issues, improving overall call quality and accuracy. Its advanced routing algorithms ensure that calls are completed quickly and reliably. So CPaaS and UCaaS platforms can look to SIP termination services to provide exceptional call quality, budget-friendly pricing, global reach, scalability, and enhanced accuracy that ensures seamless communication.

Enterprises with a multi-country presence can use SIP termination to reach customers worldwide, without the cost of setting up physical phone lines in different regions. A simple SIP connection eliminates the requirement for the costly physical infrastructure needed for making calls to any part of the world. In fact, SIP termination can significantly reduce long-distance and international calling costs compared to traditional phone lines.

For hosted PBX and contact center software providers, SIP termination offers high-definition voice quality, especially when using a reliable provider and sufficient bandwidth. In combination with other VoIP features, SIP termination can enable such organizations to leverage advanced features like call forwarding, conferencing, and caller ID customization.

Retail vs. Wholesale SIP Termination

Retail SIP termination typically caters to individual users or small businesses, who need to handle  lower volumes of calls. Services may include basic features like call quality monitoring and support. Pricing for the retail model usually involves higher per-minute rates, due to the smaller call volume and individual user costs. 

In wholesale SIP termination, larger businesses, carriers, and VoIP providers require high-volume call termination. These very high call volumes tend to attract significantly lower per-minute rates than the retail pricing model, due to bulk purchasing and economies of scale.

Wholesale SIP termination providers tend to invest in high-quality networks that deliver reliable and clear voice services. They will often offer redundant infrastructure and failover solutions, minimizing downtime and ensuring business continuity.

Wholesale providers will often offer more sophisticated features, such as enhanced CLI/NCLI access and support services backed by Service Level Agreement (SLA) guarantees.

How to Evaluate a SIP Termination Provider

When making your assessment of SIP  termination providers, keep the following criteria in mind:

Route Quality

The provider should offer a reliable network which minimizes downtime and reduces the likelihood of dropped calls, and guarantees a high standard of call quality, with clear voice communication and minimal latency.

With some countries imposing restrictions on Calling Line Identification (CLI) routes, you should look for a SIP termination provider that offers NCLI (or Non-CLI) routing options.

To cater for the widest possible range of clients, look for a provider that can interconnect networks that use Time Division Multiplexing (TDM) without problems or additional charges.

Global Coverage and Redundancy

Look for a SIP termination provider with extensive global coverage, and direct connections to major carriers and networks.

A reliable provider will also have a robust network infrastructure, redundant systems, and proactive monitoring to minimize downtime and ensure consistent service.

Porting and Interconnect Capabilities

Make sure that the SIP termination provider supports number porting, as this allows customers to retain their existing phone numbers when switching providers. The provider should be able to guarantee zero downtime during the porting process.

You should also investigate the provider’s interconnect capabilities, as these are instrumental in enabling users on different SIP networks to communicate with each other.

Real-time Monitoring and Fraud Protection

Look for a provider with effective fraud detection and prevention mechanisms. Ideally, these should include real-time network monitoring and dedicated fraud prevention tools. Your SIP termination provider should have robust security measures in place, such as encryption and firewalls, to protect against unauthorized access and data breaches.

You should also ensure that the provider can give verified proof of their compliance status, in terms of industry and region specific regulatory frameworks.

Billing Transparency and Rate Management

Consider only a SIP termination provider with transparent pricing models that don’t include hidden fees or unexpected charges, such as setup or maintenance fees.

Compare rates among providers to ensure that you’re getting the best deal. Consider providers that offer flexible pricing models, such as tiered or volume-based pricing. Note that customized rates can provide a tailored approach to wholesale SIP termination pricing, offering flexibility to meet specific business needs.

Why Global Carriers and Platforms Choose IDT Express

For telecom resellers, VoIP providers, CPaaS platforms, and enterprise IT teams, IDT Express brings 20+ years of voice experience to its SIP termination offerings. Its  focus on technological innovation and its ability to handle large call volumes makes IDT Express a strong choice for businesses seeking efficient and scalable VoIP solutions.

IDT Express’s fully redundant private network offers real-time routing and quality optimization, and ensures maximum uptime and continuous service, minimizing disruptions. IDT’s commitment to excellence is reflected in the network’s ability to handle large call volumes and manage factors like jitter, packet loss, and ping, which can impact SIP termination efficiency and VoIP call quality.

With its extensive global reach and number availability, IDT Express provides SIP termination in a wide range of countries, including access to local and toll-free numbers. This extensive footprint enables carriers and platforms to connect with customers and partners globally, ensuring seamless communication across borders. IDT Express offers Location Routing Numbers for efficient call management and redirection, ensuring that calls reach their appropriate destination.

Online portals and tools are available for managing IDT Express services, including features for reporting, number allocation, and fraud prevention. Easy Application Programming Interface (API) integration ensures compatibility with enterprise business systems, as well as integrations with platforms like Microsoft Teams. IDT Express even offers solutions like STIR/SHAKEN Verification, fraud detection and dynamic blocking, for enhanced security and call authentication.

IDT Express provides exclusive wholesale pricing and flexible options tailored to different business needs. The platform leverages its scale and infrastructure to enable IDT Express to negotiate favorable rates and offer competitive pricing on SIP termination, and competitive global rates for CLI & NCLI. This approach allows carriers and platforms to manage their costs effectively while ensuring high-quality service.

IDT Express’s SIP termination and SIP trunking solutions are designed to be scalable, allowing businesses to easily adjust their capacity based on demand. This is particularly useful for handling seasonal peaks or unexpected call volume increases without the need for expensive infrastructure upgrades. The IDT Express platform’s SIP trunking flexibility also allows for easy integration with mobile devices and remote users, supporting unified communications strategies.

Ready to scale your outbound voice traffic? Talk to our SIP termination team for wholesale pricing and interconnect setup.