Call processing scenarios

Last Updated : Oct 30, 2012 |
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The following is a list of call processing scenarios for the No-cadence call classification modes and End OCM timer feature:

ISDN trunk

When connecting a classifier to a call, Communication Manager instructs the classifier to use the no-cadence call classification modes if the following conditions are satisfied:
  • The call is an OCM switch-classified call over an ISDN trunk.
  • Older releases of Communication Manager use the corresponding older AMD on or AMD off modes.
  • The Cadence Classification After Answer field on the System Parameters OCM Call Classification screen is set to N.
  • Communication Manager has received a connect message from the far end of the trunk, and satisfies one of the following:
    • The CONNECT Reliable When Call Leaves ISDN field on the ISDN Trunk Group screen is set to Y.
    • The CONNECT Reliable When Call Leaves ISDN field on the ISDN Trunk Group screen is set to N but Communication Manager has not yet received a Progress Indication message that the call is not end-to-end ISDN or the call has a non-ISDN destination address.

SIP trunk

When connecting a classifier to a call, Communication Manager instructs the classifier to use the no-cadence call classification modes if the following conditions are satisfied:
  • The call is an OCM switch-classified call over a SIP trunk.
  • Older releases of Communication Manager use the corresponding older AMD on or AMD off modes.
  • The Cadence Classification After Answer field on the System Parameters OCM Call Classification screen is set to N.
  • Communication Manager has received an answer signal from the far end of the trunk.

Other trunks (Non-ISDN & Non-SIP)

When connecting a classifier to a call, Communication Manager instructs the classifier to use the no-cadence call classification modes if the following conditions are satisfied:
  • The call is an OCM switch-classified call over a non-ISDN or a non-SIP trunk.
  • Older releases of Communication Manager use the corresponding older AMD on or AMD off modes.
  • The Cadence Classification After Answer field on the System Parameters OCM Call Classification screen is set to N.
  • The Answer Supervision Timeout field on the Trunk Group screen is set to 0.
  • The Receive Answer Supervision field on the Trunk Group screen is set to y.
  • Communication Manager has received an answer signal from the far end of the trunk.

Mixture of old and new classifiers

If an IP-connected gateway or port network has a mixture of new classifiers that understand the no-cadence call classification modes and old classifiers that do not understand the no-cadence call classification modes, call processing tries to use the new classifiers for OCM calls. If all new classifiers are busy, call processing uses the old classifiers for OCM calls.

End OCM timer

  • If the End OCM After Answer timer field is set to a non-blank value, Communication Manager starts the timer for OCM calls after receiving a Connect message or an answer supervision signal from the network.
  • When the End OCM timer expires, Communication Manager connects the originating end of the call to the extension administered in the End of OCM Intercept Extension field on the Location Parameters screen.

Active VDN

If CTI application requests a third party make call with an originating VDN, Communication Manager sets the originating VDN as the active VDN. When the End OCM timer expires, Communication Manager re-routes the call to End of OCM Intercept Extension. If the Allow VDN Override field is set to n, the End of OCM Intercept Extension starts processing the call but internal to Communication Manager the active VDN is still remembered as the originating VDN.