High Availability Software for the Intel® NetStructureTM ZT 4901 Technical Product Specification 17
Introduction
2.2.3 Backplane
The RSS system backplane supports two CompactPCI buses accessible by both Redundant Hosts.
In Active-Standby mode, the active processor board controls the buses (Active Host) and the
standby processor board is isolated from the backplane (Drone mode). By using Active-Active-
capable processor boards such as the ZT 5524, the system can be configured so that each processor
board has access to one backplane bus (Cluster mode). The backplane has separate buses for
active-to-standby processor board communication (COMM) and Host Controller functions. See
Figure 4, “High-Availability System Backplane Architecture” on page 18 for an example of a
typical High-Availability backplane.
Figure 3. RSS Host with Bridge Mezzanine Block Diagram
Base CPU Board
CPU/
Chipset xMC
HC
PCI CIC
Iso/Term Clk. Arb.
Control
Control/Status
Control/
Status
CompactPCI J1/J2
Bus Segment A
Interboard
Connector Interboard
Connector
Xreq
Bridge Mezzanine
PCI
CIC
Iso/TermClk.Arb.
Control
CompactPCI J1/J2
Bus Segment B
Xreq