Hardware (sh calender) and System (sh clock). What's the difference?

[dathurber]

On higher end routers there are two clocks - system & hardware. What is the difference? and is it important that the two are sync'd with each other?

Timestamps seem to be using the system clock.

[donewald]

Show clock shows where the routers clock is pulling time. By default it is the hardware calendar. This is why the output looks the same to you. If you set up the router for NTP for example it would not look the same. "show clock detail" will show where the router's clock is pulled from.

Default

7200-1#sh clock det

*19:17:12.731 UTC Mon Jan 13 2003

Time source is hardware calendar

with NTP

7200-1#sh clock det

19:12:39.715 UTC Mon Jan 13 2003

Time source is NTP

Hope this helps you,

Don