HP 9000 V2500 SCA, Operator'S Manual

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6 Chapter 1
Overview
V-Class Server Architecture
V-Class Server Architecture
The V2500/V2600 server has a powerful set of interconnecting hardware
components that allow the server’s processors, memory, and I/O
components to operate with minimal interruptions or contentions for
resources.
The processor agents serve as a bus connection for a subset of the
system’s processors. Memory controllers provide cache-coherent access to
a large, shared memory. PCI controllers are the connections for PCI I/O
cards.
CTI controllers are an SCA feature used only in multiple-cabinet servers.
The CTI controllers are connected to memory controllers and provide
high-bandwidth connections to other cabinets that comprise the server.
See Figure 11 on page 16 for an overview of cross-cabinet CTI
connections.
V2500/V2600 Crossbar Interconnection
The primary interconnecting component of each V2500/V2600 server
cabinet is the HyperPlane Crossbar, which provides connections from
processors and I/O to memory.
The V2500/V2600 crossbar is a non-blocking 8x8 crossbar, which
supports eight send messages and eight receive messages
simultaneously. This crossbar provides a central connection among the
processor agents, memory controllers, and PCI controllers within a
V2500/V2600 cabinet. On multiple-cabinet V2500/V2600 servers high-
speed CTI interconnections provide access to “remote” memory or other
resources on remote cabinets. See “Multiple-Cabinet Server Connections”
on page 15 for multiple-cabinet information.
As Figure 7 on page 8 shows, the crossbar has four Exemplar Routing
Access Controllers (ERACs), each of which connects to 4 processor agents
and four memory controllers. All memory controllers and processor
agents connect to two separate ERACs, thus making the entire system’s
memory addressable by all processors and I/O devices in the system.