Silicon Graphics ICE XA, Hardware User'S Manual, Page: 48 / 96

30 007-6399-002
3: System Overview
Memory Channel Recommendation
It is highly recommended (though not required) that each processor on a system node board be
configured with a minimum of one DIMM for each memory channel on a processor. This will help
to ensure the best DIMM data throughput.
System InfiniBand Switch Blades
One, two or four fourteen-data-rate (FDR) InfiniBand switch blades can be used with each blade
enclosure pair configured in the SGI ICE XA system. The switch blades plug into the rear of the
blade enclosure, which reduces latency and improves air flow. The switch blades provide the
interface between compute blades within the same blade enclosure and also between compute
blades in separate blade enclosures.
The system supports a standard 36-port and premium 60-port FDR switch and future versions will
be capable of supporting a standard 36-port and premium 60-port EDR switch.
• The Standard switch has a single 36-port ASIC with 18 ports connecting to compute nodes
and 18 ports for connecting to external targets.
• The Premium switch has two 36-port ASICS with nine ports from each ASIC connecting to
compute nodes and 18 ports from each ASIC for connecting to external targets.
The difference is in connectivity. The premium switch has twice the external ports to use for
expanding the topology and creating larger configurations with a higher-bandwidth interconnect
fabric.
Note that All-to-All and Hypercube topologies do not require external InfiniBand switches, but
are built by interconnecting the internal InfiniBand switch ASICs (switch blades) in the blade
enclosure. The single-switch ASIC and dual-switch ASIC switch blades for each enclosure are
not
interchangeable without re-configuration of the system. The outward appearance of the two types
is very similar, but differs in regards to the number and location of QSFP ports.
Enclosures using one or two FDR switch blades are available in certain specific configurations. A
single-switch blade within a blade enclosure supports a single-plane InfiniBand topology. A
blade-enclosure using dual-node blades must use four switch blades to support a single-plane
topology. Check with your SGI sales or service representative for additional information on
availability. Any external switch blade ports not used to support the IB system fabric may be
connected to optional service nodes or InfiniBand mass storage. Check with your SGI sales or
service representative for information on available options.