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## 2.2.3 System control 

The various system elements are managed through the FSPs. An FSP is based on the IBM PowerPCfi microprocessor technology. Each FSP card has two ports to connect to two internal Ethernet LANs, through system control hubs (SCH1 and SCH2). The FSPs communicate with the SEs and provide a subsystem interface (SSI) for controlling components. 

Figure 2-11 shows a conceptual overview of the system control design. 

<img src='content_image/989456.jpg'>

Note:  The maximum configuration has four CPC drawers and five PCIe or I/O drawers for z14. The various supported FSP connections are referenced in Figure 2-11. 

A typical FSP operation is to control a power supply. An SE sends a command to the FSP to start the power supply. The FSP (by using SSI connections) cycles the various components of the power supply, monitors the success of each step and the resulting voltages, and reports this status to the SE. 

Most system elements are duplexed ( n +1), and each element has at least one FSP. Two internal Ethernet LANs and two SEs, for redundancy, and crossover capability between the LANs, are available so that both SEs can operate on both LANs. 

The Hardware Management Consoles (HMCs) and SEs are connected directly to one or two Ethernet Customer LANs. One or more HMCs can be used. 

