What is SIP recording (SIPREC)?

by Jose Luis Perez May 13, 2020
What is SIP recording (SIPREC)?

Session Recording Protocol (SIPREC) is an open SIP based protocol for call recording. The standard is defined by Internet Engineering Task Force (IETF). It is compatible with many telephone platforms and providers of call recording systems. Session controllers (SBC) that support the SIPREC interface

Session border controllers (SBC) that support SIPREC interface

  • AudioCodes Mediant
  • Avaya
  • Cisco
  • Genband
  • Metaswitch Perimeta
  • Oracle / AcmePacket
  • Sonus

Hosted PBX platforms that support SIPREC interface

  • BroadWorks
  • Metaswitch

SIPREC protocol


SIPREC standard defines a protocol used to interact between a Session Recording Client (SRC) (the role played by the PBX system or the Session Edge Controller) and a Session Recording Server (SRS) (a third-party call recording solution, such as Recordia).

The following illustration shows two endpoints- SIP users. The communication session is established through the recording device and the session is being recorded by an SRC and SRS.

The session recording client has access to the media path between the users. The SRC then establishes the recording session with the SRS and sends replicated media to the SRS. The SRC is also responsible for delivering metadata to the SRS, such as participant information (phone number, the call, etc.) in XML format. The standard also allows the extension of sent metadata. Providers are free to send additional metadata attributes that are specific to their telephone system. For example, BroadWorks sends the values “service provider ID”, “group ID” and “user ID”. Metaswitch sends “Business Group Name” and other attributes.

It should be noted that an SRC is a logical function. Its capabilities can be implemented in a session border controller, a SIP media gateway, a SIP phone or a SIP media server integrated with an application server.

Benefits for customers

Lower acquisition cost. The cost of implementing a recording system based on Premise can be high, which requires a large capital investment and is generally beyond the reach of many companies. Recordia’s Cloud Computing architecture allows you to achieve economies of scale with the consolidation of IT staff and hardware resources.

No initial investments. Customers pay a monthly fee. The call recording service is provided using the software model as a service (SaaS). Without administration or maintenance costs, the software is managed by the service provider.

Benefits for the service provider

A hosted call recording service offers a great opportunity to generate revenue for service providers, allowing them to reach new markets, attract new customers and expand their portfolio of solutions, such as our cloud solutions: Recordia and eComfax.

Call recording is a critical and indispensable requirement in many business communications environments, such as call centers and companies in the financial sector. In some of these sectors, all calls must be registered for regulatory and compliance reasons. In others, calls can be recorded for quality control or business analysis. Service providers can gain a competitive advantage with cloud call recording solution.

High availability

Most SIPREC protocol implementations provide high availability architecture support.

Because SIPREC is based on the SIP protocol, it supports proven techniques in the field, such as DNS SRV, for load balancing and self-tuning.

In addition to that, many telephone platform providers implement patented solutions to support multiple recording servers simultaneously. It usually allows you to configure a group of recording servers with some load balancing and failover policies. The telephone platform, for example, the session edge controller, periodically checks the availability of each of the recording servers in the group using some kind of ping (for example, by sending the SIP OPTIONS message and verifying the response). This mechanism allows the SBC to intelligently choose the “available” server in the group.

In addition to support on the SRC side, the SRS must support synchronization of data between servers in a cluster. Such data synchronization allows you to achieve data redundancy (each call recording is stored on at least two servers simultaneously), as well as providing a single point of access to the data and configuration (that is, it is not necessary to access each server individually). Our Recordia solution is geographically redundant, with 99.99% platform availability and 99.999999999% consistency of all recorded calls.

Interoperability of SIPREC-based solutions from different providers

The SIPREC protocol is an open standard; most suppliers aim to follow the requirements of this standard.

In simple recording scenarios, a vendor’s SIPREC-compatible system must be easily replaceable with another vendor’s system, be it the telephone platform (SRC function) or the recording system (SRS function).

In the real world, this is not always the case …

Firstly, many telephone system providers use proprietary extensions for metadata. This additional metadata may be important for end users and the recording system must analyze and process them properly. Thanks to an open standard, this proprietary data is sent in plain text XML format, usually self-descriptive.

Secondly, some implementations suffer slight deviations from the standard. For example, at least two SBC providers do not allow codec negotiation with the recording system, that is, they silently ignore the SDP response of the recording system. The recording system must be designed to receive RTP packets in unexpected codec.

Find out more about our call recording solution using SIPREC protocol.

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