What is SIPREC and how does it work?

Recording phone calls isn’t just a matter of compliance. It’s a powerful tool for businesses to gain insights and improve operations. But capturing these conversations—especially in a VoIP environment, requires specialized technology.

That’s where SIPREC— (Session Initiation Protocol recording) comes in. It’s the backbone of modern call recording, enabling the seamless capture and storage of VoIP communications. In this post, we’ll explore what SIPREC is, how it works, and how it benefits businesses already leveraging VoIP technology.

What is SIPREC?

SIPREC is an open standard protocol developed by the Internet Engineering Task Force (IETF). It defines how to handle recording VoIP communications. Unlike traditional methods of call recording that require specialized hardware, SIPREC leverages existing network infrastructure to record audio and video calls in a more integrated way.

The protocol is designed to work within the architecture of Session Initiation Protocol (SIP), which is widely used for initiating, maintaining, and terminating real-time sessions that include voice, video, and messaging applications.

How SIPREC works

The core concept of SIPREC is based on having two primary entities: the SRC and SRS. Here’s how they interact:

1. Session Recording Client (SRC): Usually part of the SIP-enabled device or service, such as a VoIP PBX (Private Branch Exchange) or a Session Border Controller (SBC). Its job is to send a copy of the live communication data to the recording server.
2. Session Recording Server (SRS): This server receives the data sent by the SRC. It’s responsible for recording, storing, and sometimes processing the media streams.

During a SIPREC-enabled call, the SRC establishes a separate SIP session with the SRS and sends duplicate media streams to it. This process happens as the call takes place, ensuring that the recording is both accurate and immediate without impacting the quality of the original call.

Typical SIPREC call flow

Let's explore a typical SIPREC call flow with Telnyx:

1. Call establishment: A call is established on the user’s SBC, which has SIPREC SRC capabilities, with RTP streams labeled A and B.
2. SIPREC initiation: The SIPREC SRC initiates a SIPREC call towards the Telnyx SIPREC SRS (siprec.telnyx.com), including the two RTP streams (A and B).
3. Recording session initiation: The Telnyx SRS initiates two SIP calls towards sip.telnyx.com, one for each RTP stream. Each call is marked with a:sendonly, indicating that RTP is only sent and not received.
4. Webhooks and metadata: Telnyx sends two call.initiated webhooks to the Voice API application URL, one for each of the SIP calls. These include the call_control_id and metadata from the original SIPREC call.
5. Voice API commands: The call_control_id from the webhooks is used to issue Voice API commands to answer and record both calls.

Now that we’ve outlined the specific steps in a typical SIPREC call flow, let’s get into the benefits that SIPREC provides, which can greatly enhance VoIP call recording processes and overall communication strategies.

Benefits of SIPREC

SIPREC offers several advantages for VoIP call recording. Here are the main ones:

Compliance and quality control

Many industries have strict regulations requiring businesses to record and store communications for a certain period. SIPREC simplifies compliance with these regulations. You can also use call recordings for quality control and training purposes, helping improve service standards.

Scalability

Since SIPREC leverages existing SIP architecture, it can scale easily with the growth of an organization. Businesses can add recording capabilities to more devices and services without significant hardware investments.

Flexibility

SIPREC isn’t tied to any specific hardware, allowing businesses to choose recording solutions that best fit their needs. It also supports multi-tenancy, making it ideal for service providers who manage communications for multiple clients.

Security

The protocol supports secure transmission methods, including Transport Layer Security (TLS), ensuring that recorded data is protected during transmission to the recording server.

Getting started with SIPREC at Telnyx

Understanding SIPREC is key to maximizing the value of your VoIP communications. As businesses continue to shift toward IP-based communications, the ability to capture and analyze voice data in real time has become more critical than ever. In addition to keeping you compliant, SIPREC is a gateway to deeper insights, enhanced customer experiences, and streamlined operations.

But to truly leverage the power of SIPREC, you need a provider that understands the intricacies of VoIP technology and offers robust, reliable solutions. That’s where Telnyx comes in. With our deep expertise in VoIP and a commitment to delivering high-quality, scalable solutions, Telnyx is perfectly positioned to support your SIPREC needs.

Whether you’re looking to ensure compliance, improve call quality, or gain actionable insights from your communications, Telnyx offers the tools and support to make it happen.