Fireplane
| Company type | Technology / Computer interconnect |
|---|---|
| Industry | Computer hardware |
| Founded | October 2000 |
| Founder | Sun Microsystems |
| Products | Internal computer interconnect technology |
Fireplane represents an internal computer interconnect engineered by Sun Microsystems as a progression from its previous Ultra Port Architecture (UPA). Launched in October 2000 alongside the Sun Blade 1000 workstation, it was rapidly integrated into the Sun Fire and Sun Fire 15K server families. These product introductions coincided with the dot-com surge and marked Sun’s strategic shift from Unix workstations toward high-capacity datacenter servers such as the Sun Starfire, designed for demanding web traffic scenarios.
The Fireplane interconnect achieved a maximum bandwidth of 67.2 GBytes/second within the Sun Blade 1000, maintaining throughput rates of 9.6 Gbit/s (equivalent to 2.4 Gbit/s per CPU). Each successive generation of Sun’s hardware architecture combined enhanced processors with corresponding interconnect improvements to boost overall system efficiency, emphasizing rapid memory access over mere CPU frequency increases. Key technologies incorporated included multiprocessor capabilities, shared memory frameworks, caching mechanisms, and uniform memory access models.
In the Sun Fire 15K chassis, up to 18 processor and memory expander boards can be installed, each equipped with four CPUs, four memory units, and I/O processors. The Fireplane utilizes an 18×18 crossbar switch setup delivering a total peak bandwidth of 43 GBytes per second.
As memory subsystems became increasingly sophisticated, ensuring cache coherence was essential. Fireplane addressed this through a dual-level cache coherence scheme that integrates both snoopy cache and directory-based methods. Snoopy buses maintain coherence within individual boards—referred to as 'snooping coherence domains'—while directory protocols manage coherence across the broader interconnect to support scalability. Systems containing up to 24 processors operate within a single domain; larger systems employ multiple domains for effective management.
Unlike Fireplane’s hybrid coherence model, competitors such as SGI and the HP Superdome line rely exclusively on directory-based coherence throughout their entire systems. For smaller-scale servers and workstations, Fireplane is fine-tuned for optimal single-domain operation by increasing clock speeds by approximately 50% to 150 MHz and doubling the number of snoops per cycle—resulting in a snooping bandwidth of 150 million addresses per second.
External links
- The Sun Fireplane Interconnect, IEEE Micro, 2002, by Alan Charlesworth (subscription)
- Sun Fire 280R Server – Just the Facts, Sun Microsystems, September 2002
- Sun Fire 15K Server Redefines the High-end, September 25, 2001