Brian Rosen

Abandoned Call and Premature Disconnect

New VersionMade clear what the text was talking about:

human or UADefined when Abandoned Call starts (after

feature negotiation between UAs)Added text in PD-3 to clarify when it

applies, and what it does/doesn't implyAdded text in PD-5 to clarify it doesn't

apply for multi-lines, and that there should be an override

Added text in PD-6 to clarify was is/isn't implied, and defined "rapidly"

Premature DisconnectPD-1 It must be possible to have the call taker

rapidly re-establish communications with a caller that attempts to prematurely disconnect from the call.

PD-2 It must be possible for the call taker to know when the caller has attempted to prematurely disconnect.

PD-3 Reconnecting the caller must work reasonably reliably under congestion conditions, especially those where call admission control is implemented.

PD-4 When PD-1 is enforced, the call taker must be able to cause alerting at the UAC which has attempted to prematurely disconnect from the emergency call.

Premature Disconnect (con’t) PD-5 When PD-1 is enforced, the caller must not be able to

place another call until the PSAP allows the call to be released. This requirement is not intended to imply a user interface with multiple lines accessible independently is locked to the single line that placed the emergency call. As mistakes can be made, an override mechanism invoked by the caller must be feasible. The implementation must fail safely such that the phone cannot be locked and unable to call for help.

PD-6 All Media and signaling streams flowing between the UAC and UAS must be maintained to the extent needed for rapid reconnection. This specifically does not imply that the call taker be able to receive live media from the UAC while the user believes the call is disconnected. "Rapidly" is in human terms: the time from when the caller reacts to the mechanism, initiating reconnect, and the time the call taker can resume conversing, and is perhaps a second.

PD-7 Control of premature disconnect is not needed in all jurisdictions. It must be possible to not invoke the function and allow premature disconnect to terminate the call as if no special features were present.

Abandoned CallAC-1 It must be possible for the PSAP or the network

that serves it to cause abandoned calls to complete and stay connected.

AC-2 AC-1 shall be applied at the earliest possible time in the call establishment process. Abandoned calls are defined as those where roundtrip signaling messages are completed between the UAS and the UAC necessary to invoke the mechanism. Calls disconnected before that time are not considered abandoned.

AC-3 Control of abandoned call is not needed in all jurisdictions. It must be possible to not invoke the function and allow calls to be abandoned as if no special features were present. Enabling or disabling must be dynamic, so that it can be enforced or not depending on conditions at the UAS.

NENA asked for two more editsPD-2 It must be possible for the call taker to know when

the caller has attempted to prematurely disconnect and conversely, when a caller attempts to reconnect after having previously attempted to disconnect.

This change is necessary to capture the capability for the call taker to know when a caller is attempting to reconnect.

PD-4 When PD-1 is enforced, the call taker must be able to cause alerting at the UAC in situations where the caller has attempted to prematurely disconnect from the emergency call or, when the caller has gone silent without having disconnected.Rationale: The caller may believe they have disconnected or

is unable to speak. The ability to alert is needed to encourage the caller, or someone in its surroundings, to reconnect with the call taker.

This change is necessary to capture the capability for the call taker to cause alerting at the UAC when the caller is deemed to be still connected but is not verbally responding.

Next StepsAccept as work group itemPresumably, assign to design team to finish

and suggest a mechanism