HP BladeSystem c-Class architecture Technology brief, 4th edition

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NonStop signal midplane provides flexibility
The BladeSystem c-Class uses a high-speed, NonStop signal midplane that supports multiple high-
speed fabrics. It is unique because it can use the same technology for the physical traces to transmit
Ethernet, Fibre Channel, InfiniBand, or SAS signals. As a result, you can fill the interconnect bays with
a variety of interconnect modules, depending on your application needs.
Physical layer similarities among I/O fabrics
The basis of serialized I/O protocols such as Ethernet, Fibre Channel, SAS, and InfiniBand is a
physical layer that uses multiples of four traces with a SerDes (serializer/deserializer) interface. The
backplane Ethernet standards of 1000 Base KX, 10G-Base-KR, and the 8Gb Fibre Channel standard
use a similar four-trace SerDes interface. Consolidating and sharing the traces between different
protocols creates an efficient midplane design.
Figure 7 illustrates the logical overlay of the physical lanes onto sets of four traces. Interfaces such as
GbE or Fibre Channel need only a 1x lane (a single set of four traces). Higher bandwidth interfaces,
such as InfiniBand, need up to four lanes. Your choice of network fabrics dictates whether the
interconnect module form factor needs to be single-wide (for a 1x/2x connection) or double-wide (for
a 4x connection).
By logically overlaying the traces, we avoid:
• Replicating traces on the NonStop signal midplane to support each type of fabric
• Large numbers of signal pins for the interconnect module connectors.
This simplifies the interconnect module connectors and uses midplane real estate efficiently.
Figure 7: Lanes (sets of four traces) in the signal midplane support 1-, 2- , or 4-lane standard protocols.
Connectivity between blades and interconnect modules
The c-Class server blades use mezzanine cards to connect to various network fabrics. The mezzanine
cards on the server blades connect to the interconnect modules through independent traces on the
NonStop signal midplane.
Connections differ depending on the enclosure.