NonStop S-Series Planning and Configuration Guide (G06.29+)

HP NonStop S-Series Planning and Configuration Guide—523303-021
2-1
2
The ServerNet Communications
Network
The ServerNet communications network is a low-cost, high-speed network within a
NonStop S-series system that connects processors to each other and to peripheral
controllers.
This network offers the interconnectivity of a standard network, but does not depend on
shared resources such as interprocessor buses or I/O channels.
Instead, the ServerNet communications network is implemented using the ServerNet
architecture, which is wormhole-routed, full-duplex, packet-switched, and point-to-
point. This network offers low cost, low latency, low software overhead, high
bandwidth, and parallel operation.
In the ServerNet architecture, each processor maintains two independent paths to
other processors, I/O devices, and ServerNet adapters. These dual paths can be used
simultaneously to improve performance, while ensuring that no single failure disrupts
communications among the remaining system components.
Flexibility of the ServerNet Architecture 2-2
Concurrent Messages 2-2
Interconnected Components 2-2
Fault Tolerance for Complex Operations 2-2
Diagramming the ServerNet Communications Network 2-3
Simplified Logical Diagrams 2-3
Detailed Logical Diagrams 2-4
How Logical Diagrams Relate to Server Hardware 2-7
Comparison to NonStop K-Series Systems 2-10