Clarification on SendToVRU node

Question

Hi All,
We have ICM  integrated with CVP using Type 10 network vru. 
I see there is one particular Label and correlation ID returned back to cvp when it encounters send to vru node for establishing VRU leg.
And there are many labels configured under this Routing client and do not see any default label for it.
I have gone through some documents and all mention just that a special label will be transferred to CVP.
I have also got to know from seniors that the very first label configured for this routing client will be returned.
I would like to have some clarification on which label will be returned and if it is sending very first label configured, is there any cisco document I can reference?
Thanks all in advance

Answer 1

there is nothing such very first label.
the net vru label is returned to routing client when script encounters send to VRU.
it is also sent out to routing clients when script has to run micro app or CVP application and it has not encountered a send to VRU node in Script execution.
ICM will decide what label to which routing client based on network VRU explored label configuration.
the label will be appended with corr id and send to the routing client.
if routing client is CVP:
now if your routing client is CVP, the label will map to VXML gateway and the VXML gateway will be configured with bootstrap application.
the bootstrap application will send htttp CALL request to call servers IVR service and the DNIS as the label.
now based on max DNIS length configured on CVP, CVP will figure out its a post routed call and split DNIS and corr id and present it ICM using request instruction.
ICM identifies the call and the node passes from success path.
and looking at the all of above , the call is also at VXML gateway port so ICM can now request CVP to send VXML docs to gateway for execution those are nothing but your micro apps or studio app.
if Routing client is CUCM:
if CUCM is the routing client, the ICM will send label back to CUCM with corr id appended.
CUCM has to pass label to CVP call server, CUCM does this using route pattern configured to match the pattern with label. corr id should also go to CVP.
once the label reaches CVP as DNIS, CVP does the same this as discussed above. it checks the length of DNIS and splits the corr id and DNIS and presents to ICM.
ICM identifies the call and sends one more label back to CVP to reach VXML gateway.
now the story follows as above discussed with CVP. 
Hope that clears out your doubt