NonStop NS14000 Planning Guide (H06.10+)

If a cable, connection, router, or other failure occurs, only the system resources that are
downstream of the failure on the same fabric are affected. Because of the redundant ServerNet
architecture, communication takes the alternate path on the other fabric to the peer resources.
For example, if the logic board for the Y fabric fails, the downstream adapters and the storage
or communications that connect to the failed switch board are unavailable to the system through
the Y fabric. The system then switches the communication to the X fabric where all devices are
available. After the failed FRU is replaced, the affected fabric and resources connected to it are
again available to the system.
In a second scenario, if one of the ServerNet adapters fails, only the Fibre Channel or Ethernet
adapters that are connected to the failed adapter are affected. The failure has no effect on other
resources on the same or other ServerNet fabric.
System Architecture
This diagram shows elements of an example of an Integrity NonStop NS14000 system with four
triplex processors:
44 Integrity NonStop NS14000 System Description