Aculab, a leading provider of enabling technology for the communications market

Aculab provides a powerful, feature rich, RFC 3261 compliant SIP stack that is integrated with its Prosody family of IP boards and HMP software. The wide range of advanced SIP capabilities inherent in the protocol stack and accessible via the APIs is ideal for multimedia session control of many and varied, IP-based, telco or enterprise communications applications.

Fully integrated SIP

Our implementation of the RFC 3261 defined session initiation protocol has been developed in-house to provide the essential features needed by developers, integrators and equipment manufacturers for a host of IP-based communications applications. The SIP stack is highly integrated with Aculab's IP boards and HMP software and benefits from a consistent approach to the evolution and development of our APIs. The SIP service presents users with the choice of a high level API and an enhanced, lower level API, which users can access, depending on the degree of control needed by their IP-based application or service.

Proven reliability

Aculab's SIP service has proven operational reliability in our customer's service delivery platforms and is uniquely available via a software download utility for use with all of our IP board and HMP software options. Users can simply collect the session protocol software at any time, gaining a distinct advantage in terms of system cost and value per channel.

Protocol combinations

Many communications applications also require IP-based media processing functionality, such as record, playback, wideband audio conferencing, encoding/transcoding and T.38 fax. All these essential functions and more are available with Aculab's Prosody X IP media processing boards, which can be combined with SIP to deliver a wide range of powerful, cost-effective, single board or multi-board, local or distributed, fourth generation, telecom server-based solutions.

In addition, offering the same core functionality, Prosody S, Aculab's advanced HMP product offers a viable alternative to using IP boards, bringing granular scalability and cost-efficiencies to those familiar with traditional, board-based designs.

Help yourself

You can download Aculab's SIP stack at any time, via our software downloads page or you can select the call control and extended SIP APIs to read from technical documents.

For IP telephony and VoIP applications, Aculab also offers an H.323 stack, which can equally be used with its HMP software and IP or DSP boards.

More protocols

Aculab's protocol coverage also extends to the broadest range of worldwide call control and signalling protocols with appropriate regulatory approvals. The list includes many different national and international variants of CAS and ISDN (including Q.SIG and DPNSS), for operation over E1 and T1 trunks. When utilised with our DSP boards, Aculab's SIP stack is an excellent option for the creation of signalling and media gateways between TDM and IP networks - gateways like GroomerII.

For more details on the unrivalled range of protocols available, including H.323, SIP and SS7, see the protocols and approvals page.

If you wish to discuss any protocol or signalling requirements, please talk to your Account Manager or email sales@aculab.com

Target applications

Aculab's IP enabled components were designed from the beginning around an IP core. This enables market aware developers, systems integrators and equipment manufacturers alike to readily create high-performance, fourth generation media processing servers and subsystems using our RFC 3261 compliant SIP stack. For an indication of what businesses just like yours are able to achieve, take a look at our solutions pages.

The following are examples of the kind of applications or service delivery platforms that could be competitively enhanced by using SIP:

Product benefits

For more details on the unrivalled range of protocols available from Aculab, including H.323 and SS7, see protocols and approvals.

You can download Aculab's SIP stack at any time, via the software downloads page.

If you wish to discuss any protocol or signalling requirements, please talk to your Account Manager or email sales@aculab.com

Protocol independence

The combination of Aculab's SIP service and Prosody X or Prosody S using high level APIs that are common across a wide range of IP and TDM protocols and formats, including SIP, H.323, SS7 (C7), DPNSS, Q.931, and Q.SIG, readily enables the creation of a variety of communications solutions. However, despite the core APIs being common, IP calls using SIP can enable many call control scenarios that are simply not possible with TDM trunking and protocols. Aculab also provides a low level SIP API extension to give access to SIP features that cannot be represented in a protocol independent manner.

Advanced features

The lower level SIP API exposes many advanced features and is offered to provide a greater degree of application control of SIP sessions. It enables full access to the power of SIP through custom headers in the SIP INVITE and application configuration of session description protocol (SDP) for media negotiation, including non-audio payload types, and multiple RTP streams. It also includes third party call control, enabling the construction of complex IP centric applications, such as IP contact centres, with rich media and call control features.

Third party session control

With some media processing boards, a signalling channel will depend on a media channel on a 1:1 basis and both will be terminated in the same place as is the case for TDM calls. Third party session control with Aculab's SIP service, implemented according to IETF RFC 3725, provides the ability to independently terminate media and signalling connections. This characteristic enables much more efficient use of the media processing resources available from an IP board or HMP software configuration and lets users specify the optimal provisioning for a given application. Through the SIP API, the application retains full session control throughout a call - for both signalling and media.

More advanced features

Additionally, the API provides for mid-session signalling, according to the RFC 2976 INFO method, which can be used to carry session related application level information. As mid-session signalling traverses the post set-up signalling path, other entities, such as SIP Proxy servers, can receive and act on the information. This enables supplementary service features to be implemented, which is ideal for many applications, where forwarding PSTN information, carrying DTMF digits, or even images and account balance information, can be useful.

Our SIP stacks up

Aculab's proven and reliable SIP stack already incorporates over 20 SIP related IETF RFCs and with our open approach to customer change requests the list will undoubtedly continue to grow. Support for SIP over TCP or UDP, SIPS (SIP over TLS), authentication, symmetric signalling ports, secure RTP, and STUN* are all available. See the protocols and approvals page for details of the full range of RFCs supported.

Aculab is a member of the SIP Center and the SIP Forum, and has participated in SIPit events, where its SIP stack has been successfully tested - a further endorsement of its field proven interoperability.

You can download Aculab's SIP stack at any time, via the software downloads page.If you wish to discuss any protocol or signalling requirements, please talk to your Account Manager or email sales@aculab.com