C H A P T E R
21
Online Insertion and Removal of Cards on the
Cisco cBR
•
•
What Does an OIR Do?, on page 249
•
Guidelines for Performing an OIR, on page 250
•
•
How Do I Perform an OIR?, on page 250
•
Verifying Status after an OIR, on page 251
About OIR
Online Insertion and Removal (OIR) was developed to enable you to replace faulty parts without affecting
system operation. When a card is inserted, power is available on the card, and it initializes itself to start
working.
Hot swap functionality allows the system to determine when a change occurs in the unit's physical configuration,
and reallocate the unit's resources to allow all interfaces to function adequately. This feature allows interfaces
on the card to be reconfigured while other interfaces on the router remain unchanged. The interrupt routine
must ensure that the interrupt line has reached a stable state.
The software performs the necessary tasks involved in handling the removal and insertion of the card. A
hardware interrupt is sent to the software subsystem when a hardware change is detected, and the software
reconfigures the system:
• When a card is inserted, it is analyzed and initialized in such a way that the end user can configure it
properly. The initialization routines used during OIR are the same as those called when the router is
powered on. System resources, also handled by software, are allocated to the new interface.
• When a card is removed, the resources associated with the empty slot must either be freed or altered to
indicate the change in its status.
What Does an OIR Do?
When an OIR is performed, the router:
1.
Rapidly scans the backplane for configuration changes.
Cisco Converged Broadband Routers Hardware Installation Guide
249