Call path reduction via correlation of call legs in a hairpin loop scenario
A variety of methods and systems can be used to avoid a hairpin loop scenario. For example, in a system involving a redirecting switch and a service platform switch, correlation between calling party identities for outgoing and incoming call legs can be done to identify a potential hairpin loop scenario. Upon detection of such a scenario, appropriate call legs can be released while routing the call to its destination. Correlation information can be collected from available call setup signaling parameters. The methods and systems can be applied, for example, to systems involving directory assistance call completion, voice-activated dialing, voicemail callback, and prepaid services.
1 - 21 . (canceled)
22 . A method comprising:
at a switch in a telecommunications network, initiating an outgoing call leg, wherein a first identifier is associated with the outgoing call leg;
at the switch, receiving an incoming call leg, wherein a second identifier is associated with the incoming call leg;
correlating the outgoing call leg and the incoming call leg based at least on the identifiers; and
responsive to correlating the outgoing call leg and the incoming call leg, processing the outgoing call leg and the incoming call leg as a hairpin loop.
23 . The method of claim 22 further comprising:
determining the first identifier from call setup signaling associated with the outgoing call leg; and
determining the second identifier from call setup signaling associated with the incoming call leg.
24 . The method of claim 22 further comprising:
determining the first identifier from a billing number parameter associated with an Initial Address Message associated with the outgoing call leg; and
determining the second identifier from a billing number parameter associated with an Initial Address Message associated with the incoming call leg.
25 . The method of claim 22 wherein processing the call legs as a hairpin loop comprises:
releasing the incoming call leg.
26 . The method of claim 22 wherein processing the call legs as a hairpin loop comprises:
parking a call leg; and
applying silence to the parked call leg.
27 . The method of claim 26 wherein processing the call legs as a hairpin loop further comprises:
releasing the outgoing call leg.
28 - 39 . (canceled)
40 . A method of upgrading a telecommunications switching system to avoid a hairpin loop scenario, the method comprising:
upgrading at least one switch in the switching system to implement correlation to correlate call legs in the hairpin loop scenario and release at least one call leg in a hairpin loop responsive to the correlation;
wherein the correlation is based on call setup signaling supported by the switch, and the switch accommodates a hairpin loop with at least one service platform switch that need not be upgraded to avoid the hairpin loop scenario.
41 . The method of claim 22 wherein the outgoing call leg comprises a service request.
42 . The method of claim 41 wherein the incoming call leg comprises a call leg directed back to the switch after performing processing for the service request of the outgoing call leg.
43 . The method of claim 41 wherein the outgoing call leg comprises a request for directory assistance.
44 . The method of claim 41 wherein the outgoing call leg comprises a request for accessing voicemail messages.
45 . The method of claim 41 wherein the outgoing call leg comprises a request for voice-activated dialing.
46 . The method of claim 41 wherein the outgoing call leg comprises a request for prepaid services.
47 . The method of claim 27 wherein processing the call legs as a hairpin loop further comprises:
maintaining connectivity for a call associated with the call legs.
48 . One or more computer-readable media comprising computer-executable instructions for performing a method comprising:
at a switch in a telecommunications network, initiating an outgoing call leg, wherein a first identifier is associated with the outgoing call leg;
at the switch, receiving an incoming call leg, wherein a second identifier is associated with the incoming call leg;
correlating the outgoing call leg and the incoming call leg based at least on the identifiers; and
responsive to correlating the outgoing call leg and the incoming call leg, processing the outgoing call leg and the incoming call leg as a hairpin loop.
49 . The one or more computer-readable media of claim 48 further comprising computer-executable instructions for performing the following:
determining the first identifier from call setup signaling associated with the outgoing call leg; and
determining the second identifier from call setup signaling associated with the incoming call leg.
50 . The one or more computer-readable media of claim 48 further comprising computer-executable instructions for performing the following:
determining the first identifier from a billing number parameter associated with an Initial Address Message associated with the outgoing call leg; and
determining the second identifier from a billing number parameter associated with an Initial Address Message associated with the incoming call leg.
51 . The one or more computer-readable media of claim 48 wherein processing the call legs as a hairpin loop comprises:
releasing the incoming call leg.
52 . The one or more computer-readable media of claim 48 wherein processing the call legs as a hairpin loop comprises:
parking a call leg; and
applying silence to the parked call leg.
53 . The one or more computer-readable media of claim 52 wherein processing the call legs as a hairpin loop further comprises:
releasing the outgoing call leg.