System information

Option Value/Example Description
tlscipher <cipher
string>
Specifies a list of ciphers for OpenSSL to use. Setting this is optional. To see a list
of available ciphers, run openssl ciphers -v at the command line.
a
The OpenSSL development package must be installed for Asterisk to be able to use encryption. On Ubuntu, the package is libssl-dev. On
CentOS, the package is openssl-devel.
Protocol Overview
There are two main types of messages on the Asterisk Manager Interface: manager
events and manager actions.
Manager events are one-way messages sent from Asterisk to AMI clients to report
something that has occurred on the system. See Figure 20-1 for a graphical represen-
tation of the transmission of manager events.
Figure 20-1. Manager events
Manager actions are requests from a client that have associated responses that come
back from Asterisk. That is, a manager action may be a request that Asterisk perform
some action and return the result. For example, there is an AMI action to originate a
new call. See Figure 20-2 for a graphical representation of a client sending manager
actions and receiving responses.
Other manager actions are requests for data that Asterisk knows about. For example,
there is a manager action to get a list of all active channels on the system: the details
about each channel are delivered as a manager event. When the list of results is com-
plete, a final message will be sent to indicate that the end has been reached. See Fig-
ure 20-3 for a graphical representation of a client sending this type of manager action
and receiving a list of responses.
Protocol Overview | 465