Power-on and power-off control, Device discovery, Code download – Cisco XR 12406 User Manual
Page 56: Diagnostics
Chapter 1 Cisco XR 12406 Router Overview
Line Cards
1-40
Cisco XR 12406 Router Installation Guide
OL-13831-01
Power-on and Power-off Control
Each MBus module directly controls the DC-DC converters on the component on
which it is mounted, based on commands the component receives from its
on-board EPROM and from the route processor. Each MBus module is tied
directly to DC voltage from the alarm card.
When power is applied to the router, all MBus modules immediately power on.
The MBus modules on the route processor and CSC immediately turn on the
DC-DC converter, powering up the respective card. The line card MBus module
waits to power on the line card until it receives a command from the route
processor.
Device Discovery
The route processor uses the MBus to detect the system configuration. The route
processor sends a message over the MBus requesting identity information from
all installed devices. The responses provide component type, as well as slot
numbers for the line cards, CSCs, SFCs, and alarm cards.
Code Download
A portion of the line card operating software can be downloaded from the route
processor to the line card over the MBus. Because the MBus is relatively slow
compared to the switch fabric, only enough code is downloaded to the line card
for it to access the switch fabric and complete the download process.
Diagnostics
The diagnostic software image is downloaded from the route processor to the line
card during the test sequence.