Cisco C8540-3CLK enterprise networking (router/Catalyst switch/UCS families) Switch / Carrier Ethernet Line Card

The Cisco C8540-3CLK is a Stratum 3 clock module for the Catalyst 8540 platform (the 8540 CSR Campus Switch Router / MSR Multiservice Switch Router family). Stratum 3 timing accuracy is a defined telecom clock-quality standard, and a clock module of this precision was needed on 8540 deployments carrying ATM or other timing-sensitive traffic.

Such traffic requires a synchronised network clock reference rather than relying on free-running local oscillators in each device. Cisco’s Catalyst 8540 platform has since reached end-of-life and end-of-support status, so replacement spares such as this clock module are increasingly relied on to keep existing 8540-based installations running rather than sourced from Cisco directly. A genuine clock module is the standard way to restore synchronised timing on a chassis where the original module has failed. Tech-Star (UK-based, shipped worldwide) can confirm compatibility with your specific 8540 configuration on request.