Callmanager TRANSFER CALL HAIRPINNING

[pbarman]

When I receive an incoming call from PSTN to an IP Phone, and I transfer the call back to another PSTN number (so the IP phone drops at this point), the two PSTN numbers are now connected and talking to each other. The call still uses the PRI channels of our voice gateway that was used for the incoming and outgoing transferred call. A 6608 and h323 gateway behaves the same way.

Is there anyway we can avoid this so that when a incoming external call is transferred to an external number, it should release the channels of my gateway ???

[paul.harrison]

Unfortunately there is no way of preventing this.

The feature you require is route optimisation which is not supported on either the 6608 nor any of the IOS gateways, and more importantly it is unlikely to be supported by your service provider.

Route optimisation is supported as part of the q-sig and DPNSS feture sets of many PBX, but not Cisco.

Many q-sig-only PBX do not support route optimisation.

You also have to look at the service providers view, if you send an incoming call back out to another destination, and they optimise the call, who pays the bill. The caller, what if you just transfered them to a premium rate number? You, but you will argue that you no longer participated in the call and you also have no control over how long the call lasts?

You can see why they wouldn't want to do it.

Paul

[pbarman]

Thanks for the information.