Title: ADS - LI Problems Handling Exception Handling, Abort Situations

PDR Reference:                   	98120002
Originator Reference:            	aciads08 
SARPs Document Reference:        	ADS SARPs Sections 2.2.1.5.3.16.4 and 
						2.2.1.5.3.16.4.1
Status:                         	RESOLVED             
Impact :					B (Bug)
PDR Revision Date:              	21/01/99 (PROPOSED -> RESOLVED)
						19/01/99 (ACCEPTED -> PROPOSED)
						18/01/99 (SUBMITTED -> ACCEPTED)
PDR Submission Date:            	03/12/98
Submitting State/Organization:    	AIRSYS ATM (ACI)
Submitting Author Name:          	Ilkiewicz, M / Stokes, S.
Submitting Author E-mail Address: 	michel.ilkiewicz@cdv.vly.sextant.
						thomson-csf.com, shawn.stokes@atnsi.com
Submitting Author Supplemental 
Contact Information:
SARPs Date:                    	IV2.2, IV2.3 (Doc 9705 Ed. 1)
SARPs Language:                 	English

Summary of Defect:

There are two related LI Exception Handling, Abort problems:

The ADS SARPs, Section 2.2.1.5.3.16.4.1 only covers the case where LI is in the LI-A-START or LI-A-ACTIVE state, however it should take the same action if in the LI-A-IDLE state and the Dialogue Service Interface is waiting for a response to a Start Indication (that was determined to be invalid by LI and thus the LI requested that the AB module abort), the LI should invoke the D-ABORT request primitive rather than ignore.

Sections 2.2.1.5.4.2, 2.2.1.5.4.3.1, 2.2.1.5.4.4.1, 2.2.1.5.4.7.1, 2.2.1.5.4.7.2, and 2.2.1.5.4.8.1 are exception handling requirements which include covering cases where a D-START indication is received by the LI process and determined to be invalid.  These exception handling requirements indicate that the LI should request the AB process to Abort and it implies that the LI should remain in the same state.  In order for the D-START indication to be received, the LI must be in LI-IDLE state and thus the "current state" would be the LI-IDLE state.

It is recommended then that Section 2.2.1.5.3.16.4.1 be expanded to cover the case where the LI is in the idle state and had previously requested the AB module to abort in response to a received D-START indication primitive.

In addition, 2.2.1.5.3.16.4 refers to the ground AB module, but clearly it is the air AB module.  Also 2.2.1.5.3.16.4.1 b) indicates LI-G-IDLE state, but should be LI-A-IDLE state.

Assigned SME:                              Sub-Volume II SME

Proposed SARPs amendment: 

Solution A/

1/ Change Section 2.2.1.5.3.16.4 from:
Upon receipt of a request to invoke D-ABORT from the ground AB module:

To:
Upon receipt of a request to invoke D-ABORT from the air AB module:

2/ Change Section 2.2.1.5.3.16.4.1 from:
If  in the LI-A-START or LI-A-ACTIVE state, the air LI module shall:

To:
If the air LI module had previously requested the AB module to abort in response to a received invalid D-START indication primitive and the LI had not received an abort request response from the AB module yet or if in the LI-A-START or LI-A-ACTIVE state, the air LI module shall:

3/ Change Section 2.2.1.5.3.16.4.1 b) from:
b) enter the LI-G-IDLE state.

To:
b) enter the LI-A-IDLE state

Solution B/

Change 1 above is already covered by PDR 98050004 Item 7.
Change 3 above is already covered by PDR 98050004 Item 8.

Change 2 above is too complex. The proposed change is as follows

Change in section 2.2.1.5.3.16.4.1 from:
If in the LI-A-START or LI-A-ACTIVE state, the air LI module shall:
a) Invoke D-ABORT request with the parameter values supplied, and

to:
The air LI module shall:
b) If a dialogue exists, invoke D-ABORT request with the parameter values supplied, and

SME Recommendation to CCB:                 

CCB Decision:                   	atnp_ccb_chair (03/12/98): SUBMITTED
						CCB-8 (Honolulu) : ACCEPTED (18/01/99)
						CCB-8a (Honolulu) : RESOLVED (21/01/99)
								With Solution B/