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JUNOSg 3.0 G10 CMTS Hardware Guide
24
The midplane is partitioned into domains A and B as described in Table5. This is required by
the bus length restrictions stipulated in the cPCI specification. The power supplies and power
distribution panels are also separated into domains A and B.
Table 5: Midplane Configuration
The division of the domains is between slots 6 and 7. Each domain includes up to four
DOCSIS Modules, a NIC Module, and a Chassis Control Module in the front, and up to four
HFC Connector Modules or SIMs, a NIC Access Module, and a Hard Disk Module in the rear.
The number of modules depends on your planned capacity.
The domains are bridged by the Chassis Control Module. Slots 6 and 7 are keyed to accept
only a Chassis Control Module in the front and a Hard Disk Module in the rear. Peripheral
interrupts, clocks, and bus arbitration signals are routed to these system slots. Conti nuity of
the bus across the midplane is accomplished by the two cPCI buses extending beyond their
system slots to connect with the system slot of the other domain, as shown in Figure 10 on
page 25. The electrical connection of t he Chassis Control Module to both buses is controlled
by a PCI-to-PCI bridge in the module.
Domain Slot Front of Midplane Rear of Midplane
A 1 DOCSIS Module HFC Connector Module or SIM
2 DOCSIS M odule HFC Connector Module or SIM
3 DOCSIS Module HFC Connector Module or SIM
4 DOCSIS M odule HFC Connector Module or SIM
5 NIC Module NIC Access Module
6 Chassis Control Module CCM Access Module
B 7 Chassis Control Module CCM Access Module
8Blank Blank
B 9 NIC Module NIC Access Module
10 DOCSIS Module HFC Connector Module or SIM
11 DOCSIS Module HFC Connector Module or SIM
12 DOCSIS Module HFC Connector Module or SIM
13 DOCSIS Module HFC Connector Module or SIM
Release 3.0 does not support Chassis Control Module
redundancy.