When replacing afabric interconnectin a Cisco Unified Computing System (UCS), the recommended procedure tominimize traffic disruptionis touse the fabric evacuation procedure on the subordinate fabric interconnect. This ensures that traffic is redirected to the other (active) fabric interconnect, allowing the system to maintain connectivity while one interconnect is replaced.
* High availability should remain enabled to preserve redundancy.
* Powering down both interconnects would cause a complete outage.
* Disconnecting cables without graceful evacuation can result in traffic loss.
Reference:Supporting Cisco Devices for Field Technicians (FLDTEC) - Maintenance and RMA Procedures

Explanation:

A # Line cards
Provide the physicalinterfaces for network connectivity.
B # Route processor cards
Manage routing functions and system control.
C # Transceivers
Installed in the ports of line cards for optical/electrical signal transmission.
D # Power supplies
Provide power to themodular system and are hot-swappable.
Cisco'sNCS 5500 Seriesis designed for service provider and data center deployments. The FLDTEC course outlines the layout of FRUs in modular platforms like this one:
A - Line Cards: Located in the upper slots, these modules handle the bulk of switching and forwarding functions.
B - Route Processor Cards (RP Cards): Positioned centrally, these provide management and control plane services for the router.
C - Transceivers: Installed into the line cards, transceivers provide physical connectivity through optical or copper interfaces.
D - Power Supplies: Located in the bottom rear section, these modules provide redundant and hot-swappable power to the chassis.
Recognizing each FRU visually and functionally is critical when performingRMA procedures,component diagnostics, orhardware upgradesin the field.

When installing a fan module in a Cisco Nexus fixed-configuration switch, it's crucial to ensure that the airflowdirection of the new fan matches the existing airflow configuration. Mismatched airflow directions can lead to inefficient cooling or even overheating of components, potentially affecting the performance or lifespan of the switch.
Cisco offers fan modules infront-to-backorback-to-frontairflow variants, and consistency is required for proper thermal management. These modules are also typically hot-swappable, meaning powering down the switch is not necessary.
Reference:Supporting Cisco Devices for Field Technicians (FLDTEC) - Maintenance and RMA Procedures

During password recovery on Cisco devices, the configuration register is modified to instruct the device to bypass the startup configuration stored in NVRAM. This allows administrators to access the device without being prompted for existing passwords. The standard procedure involves changing the configuration register value to0x2142, which tells the device to ignore the startup configuration during the next boot. Once access is gained, the administrator can reset passwords and then restore the original configuration by resetting the configuration register to its default value, typically0x2102.
Reference:Supporting Cisco Devices for Field Technicians (FLDTEC) - Troubleshooting Methodologies

A speed mismatch occurs when two connected Ethernet devices are configured to operate at different speeds.
In scenario A, one device is manually set to 1 Gbps, while the other is set to 100 Mbps. Since both ends are hard-coded to different speeds, they cannot successfully negotiate a common speed, leading to a mismatch and resulting in a failed or unstable link.
In contrast, scenario B, where both ends are manually set to the same speed, ensures compatibility and stable communication. Scenario C can lead to a duplex mismatch rather than a speed mismatch; the auto-negotiating end may default to half-duplex if it cannot determine the duplex setting of the manually configured end.
Scenario D is less common; if auto-negotiation fails, devices may revert to their lowest common speed, but this typically results in reduced performance rather than a complete mismatch.
Reference:Supporting Cisco Devices for Field Technicians (FLDTEC) - Troubleshooting Methodologies