Background

The bandwidth capabilities of Gigabit Ethernet across a backplane are a great improvement over the theoretical 533 Mbytes/sec the 66 Mhz version of cPCI supports. Performance, scalability, and reliability of CompactPCI are improved with cPSB for IP traffic.

Essentially, cPSB overlays an embedded Ethernet switching network on the cPCI backplane, accessed via the J3 connector. All subsystems operate as stand-alone "systems on a card", interfacing with each other through a network stack on top of Ethernet. CPSB increases the performance of subsystems by moving data traffic off the shared bus and onto an embedded, switched 10/100/1000 Mbit/sec Ethernet network.

Background

Are fiber optic backplanes coming soon? Well, some companies have released optical backplane concepts with special connectors on the backplane, allowing high density fiber cable to plug in. The connectors have a degree of "float" within the backplane, so that mating and alignment are eased. The supporting technology is getting more elaborate every day - from fiber management systems, to active and passive optoelectronics to optical interconnects.

True optics across the backplane is another story. Alignment is a major issue as everything needs to line up perfectly (to avoid photon loss). In standard connectors, a guide pin can help the connectors mate as copper connections slightly bend and shift to align. That can't be done with optical connections. So, a rackmount style of optical pluggability still needs to be perfected. The other issue is getting the fiber inside the layers. Developments have been made, but we'll have to see how that difficulty is overcome.