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PCI Express switches for dense bladed computing platforms

64-lane part is largest PCI express switch yet offered, says IDT

19th March 2007 - A family of seven switches extends IDT's offerings in the PCI Express interconnect product sector. IDT says it configured the chips in terms of their PCIe port and lane counts to best match the needs of designers handling communications in high-density bladed computing systems. Three of the new parts, which all maintain full line rate (2.5 Gbit/sec) throughput, manage communications between root and intelligent end-points. They range from an 8-port, 32-lane configuration to a 16-port, 64-lane part that IDT says is that largest monolithic switch available. Four devices are inter-domain PCIe switches, 2- and 3-port configurations that support address translation and non-transparent bridging between domains. The new devices support power management, and quality-of-service, data-integrity and error-handling functions that are embedded in the OSs that employ PCIe. IDT says its parts offer the lowest-available power solutions for handling PCIe traffic – if you connect a mismatched PCIe stream to a port (i.e. the switch has more lanes per port than the stream contains) the unused hardware (lanes) will automatically shut down. Nevertheless, the company says, a good understanding of the applications is critical to success because although unused lanes may not impact the power budget, they represent wasted silicon area, and hence cost. The new parts also support large payload sizes: the PCIe standard specifies that a frame may contain up to 4 kbytes of payload data. Most switches support very much less, IDT says – these parts support up to 2 kbytes, which the company says is “more than enough”. By including in its range the first 16-port, 64-lane device, this family increases scalability, the company adds.