Sonus Networks has updated its IMS (IP multimedia subsystem) middleware stack for carrier infrastructure equipment based on Linux. Updates to the company's SIP (session initiation protocol) implementation and session control components bring compliance with 3GPP's Release 7 IMS specifications, and with SAForum high-availability specifications, the vendor said.

The 3GPP specifies that SIP (session initiation protocol) be used in IMS to set up and tear down connections between IP service users. Such services could include video calling, video conferencing, instant messaging, chat, and PTT (push-to-talk) hook-ups. Sonus claims that its SIP implementation “has been the foundation for IMS Forum interoperability testing since the inception of the [SIP] Forum.” In other words, the company's software is used in interoperability testing at members-only “PlugFest” events, it said.

Sonos appears to use its reference implementation of SIP in a variety of “session control” middleware components, including:

• An “SRX” S-CSCF (serving call session control function) used to authenticate a particular service for a given session. With the new release, SRX appears to have gained support for high-availability middleware compliant with the SA Forum's AIS specification.
• An “HRX” HSS (home subscriber server), the central database for subscriber status information, such as location within the network
• A “PSX” BGCF (breakout gateway control function), which routes services between the IP network and other networks, such as the PSTN (public switched telephone network), IP-voice, and/or TDM (time division multiplexing, a kind of cellular network technology) networks

The company also offers IMS management software, border and media control middleware, and a variety of IMS applications, as shown below.

Sonus IMS stack
(Click to enlarge)

Vikram Saksena, CTO, stated, “Our goal is to provide an IMS core network that will support the delivery of enhanced services to any end-user device. With today's release, we've added scalability and reliability components.”

IMS Forum Chariman Michael Khalilian stated, “When migrating to the all IP network, interoperability is key. Sonus Networks have always been at the forefront of advocating the use of industry standards.”

 
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