IBM Power Systems 775 Manual page 43

First level interconnect: L Local
L Local (LL) connects the eight octants in the CEC drawer together via the HUB module by
using copper board wiring. Every octant in the node is connected to every other octant, as
shown in Figure 1-17.
Figure 1-17 First level local interconnect (256 cores)
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Chapter 1. Understanding the IBM Power Systems 775 Cluster