Cisco WS-X4K-CLOCK
Catalyst 4500 Clock Module
Product Highlights
When a Cisco Catalyst 4500 Series chassis experiences unexplained power-downs or erratic behavior, a failed clock module on the backplane is a common culprit that can be difficult to diagnose. The Cisco WS-X4K-CLOCK is the factory clock module designed for the Catalyst 4507R and 4510R switch chassis, providing the critical timing reference that keeps the backplane and switching fabric operating in sync.
The clock module mounts directly on the passive backplane of the Catalyst 4500 chassis, working alongside the fabric redundancy modules (mux buffers) that route traffic to the active supervisor engine. Every Catalyst 4507R and 4510R chassis ships with a clock module installed as standard; the WS-X4K-CLOCK is the orderable spare that allows network teams to keep replacement inventory on hand for rapid restoration.
As the Catalyst 4500 platform has reached End-of-Life status, sourcing genuine spare components like the WS-X4K-CLOCK becomes increasingly important for organizations that continue to operate these proven chassis in campus and data center environments. Having a spare clock module in your parts inventory minimizes downtime risk and avoids extended outages while waiting for hard-to-find components.
Features & Benefits
Chassis Timing & Synchronization
The WS-X4K-CLOCK provides the internal clock reference for the Catalyst 4500 chassis backplane. Accurate timing synchronization is essential for reliable communication between the supervisor engine and all installed line cards, ensuring stable switching fabric operation.
Backplane Integration
This module installs directly onto the passive backplane of the Catalyst 4507R or 4510R chassis, alongside the fabric redundancy modules. It is accessible from the front of the chassis once supervisor engines and switching modules are removed, simplifying replacement during scheduled maintenance windows.
Field-Replaceable Spare
Designed as a field-replaceable unit (FRU), the WS-X4K-CLOCK allows network teams to restore chassis functionality without a full chassis swap. Note that this module is not hot-swappable — the switch must be powered down before replacement. Keeping a spare on hand is critical for minimizing unplanned downtime.
EOL Inventory Protection
With the Catalyst 4500 platform at End-of-Life, sourcing genuine Cisco spare parts is increasingly challenging. Stocking a replacement WS-X4K-CLOCK protects your investment in existing infrastructure and ensures you can maintain uptime until a platform migration is completed.
Deployment Scenarios
Proactive Spare Inventory for Campus Networks
Organizations running Catalyst 4507R or 4510R chassis in campus distribution or core roles can stock the WS-X4K-CLOCK as a critical spare. If the installed clock module fails, having a replacement on-site enables rapid restoration during a maintenance window rather than waiting for an increasingly scarce EOL part.
Break/Fix Replacement for Intermittent Chassis Failures
Symptoms such as unexplained chassis power-downs, output-fail LEDs on power supplies with otherwise green status LEDs, or flashing status LEDs on switching modules and supervisor engines can indicate a failed clock or redundancy module. The WS-X4K-CLOCK is the correct replacement part to resolve clock-related backplane failures on classic Catalyst 4500 chassis.
Lab & Refurbishment Environments
IT teams rebuilding or refurbishing Catalyst 4507R/4510R chassis for lab, staging, or secondary deployment use need verified backplane components. The WS-X4K-CLOCK ensures the rebuilt chassis has a functioning clock module for reliable operation.
General
Installation
Compatibility
Compatibility Notes
Compatible Chassis
- Cisco Catalyst 4507R (WS-C4507R) — 7-slot chassis with 5 redundancy modules and 1 clock module on the backplane
- Cisco Catalyst 4510R (WS-C4510R) — 10-slot chassis
Important Notes
- The WS-X4K-CLOCK is for the classic Catalyst 4500 chassis (non-E-Series). The E-Series chassis (4507R-E, 4510R-E) use the WS-X4K-CLOCK-E instead — these are different parts.
- This module is not hot-swappable. The chassis must be fully powered down before replacement.
- Replacement requires removing all supervisor engines and switching modules to access the backplane.
- ESD precautions are required when handling this module.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| WS-X4K-CLOCK-E | Catalyst 4500 E-Series Clock Module | Designed for the E-Series chassis (4507R-E, 4510R-E); not interchangeable with the classic WS-X4K-CLOCK. |
| C4K-MUX= | Catalyst 4500 Fabric Redundancy Module (Mux Buffer) | Companion backplane component — one per line card slot; works alongside the clock module for chassis redundancy. |
| WS-X4590-E= | Catalyst 4500 E-Series Fabric Redundancy Module | E-Series fabric redundancy module; pairs with WS-X4K-CLOCK-E on E-Series chassis backplanes. |
