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Data Processing Procedures. CSTS Teleconference 23.02.2012 M. Götzelmann. Framework. Fall Meeting Approach. Data Processing Procedure PDO unconfirmed. Sequence Controlled Data Processing Procedure PDO confirmed. Buffered Data Processing Procedure PDO unconfirmed.
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Data Processing Procedures CSTS Teleconference 23.02.2012 M. Götzelmann
Framework Fall Meeting Approach Data Processing Procedure PDO unconfirmed Sequence Controlled Data Processing Procedure PDO confirmed Buffered Data Processing Procedure PDO unconfirmed Forward Synchronous Frame Processing Procedure Forward CLTU Processing Procedure Forward TC Frame Processing Procedure Specification adopted from the original DPP: Processing starts in the sequence data units are received but does not need to terminate in the same sequence Forward Space Packet Processing Procedure CSTS Teleconference - DPP
Problem 1 – Reporting of Incidents 5 4 6 5 7 4 6 7 Data unit last processed Data unit last processed Data unit last OK Status: interrupted Status: completed Data unit last OK 11 6 14 10 7 9 4 13 5 8 12 Data unit last OK Data unit last processed Status: started FSP: packet-identification-list:5, 6, 8, 10, 11, 12 waiting processed completed CSTS Teleconference - DPP
Option A Basic Procedures can handle everything, derived procedures constrain Framework Data Processing Procedure PDO unconfirmed Sequence Controlled Data Processing Procedure PDO confirmed Buffered Data Processing Procedure PDO unconfirmed Forward Synchronous Frame Processing Procedure Forward CLTU Processing Procedure Forward TC Frame Processing Procedure allow concurrent processing Forward Space Packet Processing Procedure strict sequential processing CSTS Teleconference - DPP
Option B Basic Procedures only support sequential processing, derived procedures add concurrency Framework Data Processing Procedure PDO unconfirmed Sequence Controlled Data Processing Procedure PDO confirmed Buffered Data Processing Procedure PDO unconfirmed Forward Synchronous Frame Processing Procedure Forward CLTU Processing Procedure Forward TC Frame Processing Procedure allow concurrent processing Forward Space Packet Processing Procedure strict sequential processing CSTS Teleconference - DPP
Is Option B possible? Viewpoints Data (notify Operation) Behaviour specialised basic behaviour extended behaviour general CSTS Teleconference - DPP
Problem 1 - Conclusions • Constraining basic procedures to sequential processing one data unit at a time • Simplifies the specification and implementation • Can already support a wide range of applications • Derivation of procedures supporting concurrency • Is possible for data via extension parameters • Can be argued for the behaviour (although the counter argument has some validity as well) • Proposal: in the framework only support strict sequential processing CSTS Teleconference - DPP
Problem 2 – Queue Overflow Reporting Policies: • Discard latest • Data unit last OK = 3 • Data unit last processed = 4? 9? • Discard latest • Data unit last OK = 3 • Data unit last processed = 4? 5? • Flush Queue • Data unit last OK = 3 • Data unit last processed = 4? 8? • Add data unit identification list? • User always in spite of overspecification? 9 8 7 6 5 4 3 CSTS Teleconference - DPP
Problem 3 – Inherited Notification PDO unconfirmed Policy: undefined Notification: Queue Overflow Data Processing Procedure PDO unconfirmed Sequence Controlled Data Processing Procedure PDO confirmed Buffered Data Processing Procedure PDO unconfirmed PDO unconfirmed Policy: undefined Notification: Queue Overflow PDO confirmed Policy: always discard latest Queue overflow preventedby rejecting via negative return BUT: notification queue overflow inherited CSTS Teleconference - DPP
Questions to the WG • Shall the simple DPP support concurrent processing of data units or only serialised strictly sequential processing? • Shallwe add a parameter data-unit-identification to all notifications to identify affected data units? • How shall we inform the user of what data have been discarded following a queue overflow event? • Can derived procedures simply ignore the notification type 'queue overflow' specified in the simple DDP? CSTS Teleconference - DPP