What affect does rndc have on a running named system?

[Lists User]

What happens to the nameserver when I run rndc?

rndc reload seems that is temporarily suspends the service
and the system may be off for a fraction of time.

rndc reconfig doesn't seem to have that downtime.
Is there a point in the reconfig where the nameserver stops
responding to queries and to dynamic updates?

Thanks for any insight in this.

-Steve