Response to Call Back questions

IETF 77 – AnaheimStephen McCann, RIM

Overview• Document contains some RIM responses to the 5

questions from Hannes Tschofenig, regarding Call Back behavior.

Call Back Q1• What functionality is available in today's CS

networks?

• Disabling ‘a’ party clear is likely to be implemented in some countries but we are unsure of which countries.

Call Back Q2• Is this useful functionality to have for IP-based

emergency services?

• The procedures in place for CS based emergency services should be at least the same as for IP based emergency services.

Call Back Q3• Do you envision a time-restriction on this

capability?• Example: only within one hour callbacks from the

PSAP are treated differently to normal calls.?

• The call back time needs to be configurable as it is likely to be a national matter. In some countries it may be zero.

Call Back Q4• Would you expect the call to reach primarily the

device that initiated the emergency call?

• The call back should reach the device that made the emergency call.

Call Back Q5• In some cases the device that was used to originally initiate the call

does not respond anymore to a callback (e.g. imagine a fixed line phone that was used to report a fire in a house and is out of order soon afterwards). Since the initial emergency call provided a second contact mechanism (namely the address of record) it could be used by the call taker as well. Should this communication also experience the same type of override privilege as the initially transmitted callback to the emergency caller's device ?

• PSAP’s and emergency response services should be free to use whatever means is appropriate and at their disposal to contact the caller. It is beneficial for the caller’s device to provide more information than the minimum required to the PSAP about location, identify and alternative call back options.

Additional use case• An emergency situation may change and the

caller awaiting a PSAP call back may desire that the call back is made requiring the intervention of the called user or without first alerting.

• Such a capability could be available for a limited time. Imagine someone such as a kidnapped person reporting that their life is in danger.