When a restart is performed, all channels are cleared (i.e., hung up) and all modules are reloaded. You can also instruct Asterisk to restart only when there no longer any active channels, thus preventing calls from being dropped.

Get Asterisk: The Future of Telephony now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.