Silicon Graphics SGI Altix 3700 Bx2, User Manual

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18 007-4377-002
2: System Control
System Controller Interaction
In all Altix 3700 Bx2 servers all the L1 controllers communicate with each other in the
following ways:
• All CR and NUMAlink-4 R-bricks communicate with each other through the
NUMAlink connections using low voltage differential signaling (LVDS).
• An L1 controller of an I/O brick communicates with an L1 controller of a CR-brick
via the Crosstown2 connections using serial (RS-422) signals.
• If a USB-to-Ethernet adapter is connected to either the CR or NUMAlink-4 R-brick,
the L1 system controller on that brick emulates an L2 controller. Access to the L2
functionality is made by way of an Ethernet connection.
Figure 2-2 diagrams the paths for an example console interaction between the system L1s
and a remote Ethernet based console interface.