ISS Technology Update, Volume 7 Number 3 - Newsletter

ISS Technology Update Volume 7, Number 3
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Interconnect infrastructure in the HP BladeSystem c7000 enclosure
A key component of the c7000 enclosure is the I/O infrastructure—essentially, a NonStop signal midplane with internal wiring
between the server or storage blades and the interconnect modules. The midplane is an entirely passive board. The term
passive means there are no active electrical components on the board. On one side of the board are the sixteen connectors for
the server/storage blades. Internal traces in the printed circuit board link them to eight connectors on the other side of the
board for the interconnect modules (Figure 2-1).
Figure 2-1. See-through illustration showing both the server blade connectors and the interconnect module connectors
The NonStop signal midplane uses the similar four-trace differential SerDes transmit and receive signals to support either
network-semantic protocols (such as Ethernet, Fibre Channel, and InfiniBand) or memory-semantic protocols (PCI Express).
Figure 2-2 illustrates how the physical lanes can be logically overlaid onto sets of four traces. Interfaces such as Gigabit
Ethernet (1000-base-KX) or Fibre Channel need only a 1x lane, or a single set of four traces. Higher bandwidth interfaces, such
as InfiniBand DDR, use up to four lanes.
Figure 2-2. Logically overlaying physical lanes (right) onto sets of four traces (left)