Global and Local Variables in Dial Plan
If set a variable with the prefix "&" in the DeployPatterns, it will be a Local Variable.For example: &my.variable = value
If set a variable with the prefix "&&" in the DeployPatterns, it will be a Global Variable.
For example: &&my.variable = value
The scope of a Local Variable is one SIP session which matches the related DialPlan rule.
It means the variable is valid in one session.
The scope of a Global Variable is the entire SIP Server.
It means the variable is valid for all sessions.
Example:
&net.sip.timeout.ringing = 60000
It sets 60sec for the Ringing timeout in the current SIP session.
&&net.sip.timeout.ringing = 60000
It sets 60sec for the Ringing timeout in all of SIP sessions.