先看一段简单的dialplan：

<action application="set" data="continue_on_fail=true"/>
<action application="bridge" data="user/1001"/>
<action application="log" data="ERR run here"/>
<action application="bridge" data="user/1002"/>

设置了continue_on_fail之后，如果呼叫用户1001失败，会接着execute，先打印日志，再呼叫用户1002

反之，如果不设置continue_on_fail，log和bridge这2个app就没有execute的机会了

当然也可以这样设置，指定hangup cause列表：

<action application="set" data="continue_on_fail=NORMAL_TEMPORARY_FAILURE,USER_BUSY,NO_ANSWER,TIMEOUT,NO_ROUTE_DESTINATION"/> 

<action application="bridge" data="user/1001"/>
<action application="log" data="ERR hcause = ${originate_disposition}"/>

<action application="log" data="ERR sip status code = ${sip_invite_failure_status}"/>
<action application="bridge" data="user/1002"/>

留意originate_disposition和sip_invite_failure_status这二个通道变量