FSMLabs is shipping a Carrier Grade version of its real-time Linux operating system. Carrier Grade RTLinux includes a 2.6 kernel, FSMLabs's patented real-time nanokernel, tools, and a complete, tested, validated Linux distribution, the company says. It targets Linux-based core/edge infrastructure applications for converged voice and data and wireless/wire-line access.

FSMLabs is the fourth company to register a Carrier Grade Linux product with the Open Source Development Labs (OSDL), which maintains the spec. The first was TimeSys, which says it worked closely with the OSDL to develop the system of vendor self-registration used for Carrier Grade Linux. The other two are Novell/SuSE and MontaVista.

According to FSMLabs, Carrier Grade RTLinux (CGR) stands out not only for its hard real-time capabilities, but because it implements more CGL Priority 1 requirements, with fewer exceptions, than either Novell/SuSE or TimeSys. Additionally, the company claims CGR complies more completely with Linux Standards Base requirements.

Other claimed advantages include support for SMP (symmetric multi-processing), including on multi-processor systems and multi-core CPUs, memory-protected real-time application threads, and zero-copy real-time networking.

First “full” FSMLabs Linux distribution

FSMLabs CEO Victor Yodaiken says customer demand drove the company toward Carrier Grade Linux. “During the last six months, we've had a lot of telecom interest, possibly because of our work with Juniper Networks [story]. People have been asking for integration with a CG version of Linux, and we decided our best bet would be to upgrade a standard version of Linux.”

Interest has been especially high in China, Yodaiken notes, where Red Flag Software partnered with FSMLabs on RTCore/RTLinux and RTCore/BSD sales and support in November of 2003.

According to Yodaiken, several FSMLabs engineers worked for about three months to implement Carrier Grade Linux requirements on top of Fedora. The result is a complete Linux distribution that the company distributes on a single DVD as part of CGR. Previously, FSMLabs had distributed Linux only as a minimal filesystem for embedded runtime applications. “It's our first full Linux distribution,” notes Yodaiken.

CGR also includes a new version of RTCore, the company's patented hard real-time nanokernel, upgraded to support 2.6-series kernels. And, it includes development tools based on SlickEdit.

Optionally available are the VxIT VxWorks binary compatibility layer, and LNet real-time Firewire (IEEE1394) and gigabit Ethernet networking stack, among other add-ons. Yodaiken notes, “LNet is a high-speed, low-jitter interconnect with 1394 and gigabit Ethernet support. In telecom, most people use high-end Ethernet as an interconnect. But people in robotics are using 1394, and I suspect people will start using [1394] in clusters — it's so fast.”

Real-time attributes

According to Yodaiken, CGR can achieve especially impressive real-time performance when run on SMP systems. “With standard x86 systems, you get worst case interrupt latencies of 7 microseconds, and jitter of real-time threads of 20 microseconds. That's under load, tested for a week. With CPU reservation on a multiprocessor system, you're under 2 microseconds, and sometimes under 1.”

Yodaiken defines “jitter” as the maximum time difference between when an application thread is supposed to execute, and when it actually starts to run. “Jitter, for us, is if you run a real-time thread on a fixed schedule, and you measure its worst deviance from that schedule. [CGR has] 20-40 microsecond worst case, depending on hardware. On SMP hardware, if you reserve the CPU, you can drop that by a factor of 10. Of course, most of our customers find 20-40 to be just fine.”

Traditionally, Carrier Grade Linux has been used mainly in control plane applications, leaving a more traditional RTOS such as Wind River's VxWorks or Enea's OSE to handle the data plane. However, Yodaiken says, CGR has the real-time performance needed to build carrier grade systems that handle control- and data-plane processing on the same system. Yodaiken adds, “The real advantage is getting worst-case jitter of 25 microseconds, plus four processors running Oracle or SS7.”

Another CGR advantage touted by FSMLabs is the capability to run with equal determinism on huge Xeon-based telecom servers, on multi-core chips, or on low-powered embedded processors such as x86-based NPUs (network processor units).

FSMLabs competitor MontaVista, meanwhile, last week shipped a real-time Mobilinux distribution aimed in part at single-chipset mobile phones, and the company is expected to announce a version of its Carrier Grade Edition product soon with improved real-time capabilities.

“The telecom market in general, and especially in China, has long needed the combination of hard real-time and Carrier Grade functionality now offered by FSMLabs,” commented Siyuan Huang, director of France-Telecom's Open Systems Lab.

Availability

Carrier Grade RTLinux is available now, in uniprocessor and multiprocessor versions for IA-32/x86, priced at $40K for five developer seats, including all add-ons. A basic edition without memory-protected real-time threads or real-time networking is also shipping, priced at $25K for five seats, including basic support and the Controls Kit XML/RPC add-on. FSMLabs has satellite offices in Alaska, India, Russia, Korea, and Japan, and should be contacted directly for pricing outside the US. Additionally, FSMLabs will ship a 64-bit version “within two months,” Yodaiken said.

Yodaiken says FSMLabs has already provided CGR to several customers, who are using it to build VoIP-to-POTS gateways, routers, and other telecommunications equipment. Customers commonly run it on 2- or 4-processor systems, he says, although some are using 8-processor systems. No products based on CGR are likely to have reached market as yet, though, he says.

“FSMLabs is uniquely positioned to deliver a Carrier Grade software platform to equipment manufacturers,” Yodaiken said. “We have always provided superior performance and POSIX interfaces to communications customers, and are today proud to step up to the Carrier Grade Linux challenge.”

 
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