- SPI-4.2
SPI-4.2 is a version of the
System Packet Interface published by theOptical Internetworking Forum . It was designed to be used in systems that supportOC-192 SONET interfaces and is sometimes used in10 Gigabit Ethernet based systems.A typical application of SPI-4.2 is to connect a framer device to a
network processor . It has been widely adopted by the high speed networking marketplace.The interface consists of (per direction):
* sixteenLVDS pairs for the data path
* one LVDS pair for control
* one LVDS pair for clock at half of the data rate
* twoFIFO status lines running at 1/8th of the data rate
* one status clockThe clocking is
Source-synchronous and operates around 700 MHz. Implementations of SPI-4.2 have been produced which allow somewhat higher clock rates. This is important when overhead bytes are added to incoming packets.PMC-Sierra made the original OIF contribution for SPI-4.2. That contribution was based on thePL-4 specification that was developed by PMC-Sierra in conjunction with theSATURN Development Group .The physical layer of SPI-4.2 is very similar to the
HyperTransport 1.x interface, although the logical layers are very different.External links
* [http://www.oiforum.com/public/impagreements.html OIF Interoperability Agreements]
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