Are dialplan variables per call or global?

are variables that are set in the dialplan per call or global?

example if I set variable $site to a value based on what digits a caller dialed… and that call is active say in the auto attendant portion of the dialplan…

if a second call comes into my asterisk system while the first call is active… of course $site will get set based on what that caller dialed…

will the first call’s $site be still set to its original value or will it be overwritten by the second call’s setting of the variable?

-Christopher

By default, per channel, i.e. half a call. They can be made global or to apply to a complete call.