1. protocol = messaging + semantics – Arlington state machine is for messaging – Berkeley state machines is for semantics Issue of Arlington state machine – Technically right (as far as we can tell) – Just specifies message sequences which may be already clear by ladder message sequence graphs So, no value is added to the CS doc by the SMs? But ladder graph can only show examples, and lacks rigorousness? Issue of Berkeley state machine – How timer should be handled is still open to argument I believe this model is right, but …. – Using state machines to describe semantics may define things beyond the protocol should do. The state machines should be shown as examples, not definition

2. Arlington state machines

3. NSA RA SM PA SM RA SM NSA PA SM NSA RA SM PA SM NRM NSI messages Input/output internal to an NSA PA/RA state machines which only handle message exchange and sequence (no behavior of NSA are modeled in the SM)

4. Reservi ng Reserv ed In Service Provisi oning Releasi ng Input Output red : an input/output event which is an NSI message blue : an input/output event which is not an NSI message >: Downstream input/output <: Upstream input/output rsv: reserve, prov: provision, rel: release, cncl: cancel.rq : request,.cf: confirm, gr: granted, ng: not granted Initial Requestor Agent (RA) messaging state machine Termin ated Any state Canceli ng <prov.cf <provision_complete <rsv.gr <reserve_ok <rsv.ng <reserve_ng >reserve_start >rsv.rq <rel.cf <release_complete >release_start >rel.rq >provision_start >prov.rq >cancel_start >cncl.rq <cncl.cf <cancel_complete RA SM Not necessary?

5. Reservi ng Reserv ed In Service Provisi oning Releasi ng >prov.rq >provision_start <provision_complete <prov.cf <reserve_ok <rsv.gr <reserve_ng <rsv.ng >rsv.rq >reserve_start <release_complete <rel.cf >rel.rq >release_start Initial >cncl.rq >cancel_start <cancel_complete <cncl.cf Provider Agent (PA) messaging state machine Termin ated Any state Canceli ng Input Output red : an input/output event which is an NSI message blue : an input/output event which is not an NSI message >: Downstream input/output <: Upstream input/output rsv: reserve, prov: provision, rel: release, cncl: cancel.rq : request,.cf: confirm, gr: granted, ng: not granted PA SM Not necessary?

6. NSA PA SM RA SM NSI messages Input/output internal to an NSA Example: A middle NSA which does nothing but just pass messages

7. Berkeley state machines

8. NSA NRM UR AG UP AG If we do not introduce PA/RA state machines, UR, AG, UP are modeled to directly send/receive NSI messages

9. Initial Schedu led Idle In Service Auto Start Termin ated >prov.rq (start_time) (provision) <prov.cf >prov.rq (provision) <prov.cf >rsv.rq, (reservation ok) <rsv.ok >rel.rq (release) <rel.cf (start_time)(end_time) (cancel) Input Output red : an input/output event which is an NSI message >: Downstream input/output <: Upstream input/output rsv: reserve, prov: provision, rel: release, cncl: cancel.rq : request,.cf: confirm, gr: granted, ng: not granted (event): internal event,: “all” condition Sample Ultimate Provider with NSI messages >rsv.rq, (reservation ng) <rsv.ng (end_time) (release) (cancel) >cncl.rq (cancel) <cncl.cf Any state Not necessary?

10. Reservi ng Reserv ed In Service Provisi oning Releasi ng Initial >cncl.rq >cncl.rq* <cncl.cf* <cncl.cf Termin ated Any state Canceli ng >prov.rq >prov.rq* <prov.cf* <prov.cf <rel.cf* <rel.cf >rel.rq >rel.rq* <rsv.cf* <rsv.cf <rsv.ng& <rsv.ng >cncl.rq* >rsv.rq >rsv.rq* Sample Aggregator function with NSI messages Input Output red : an input/output event which is an NSI message >: Downstream input/output <: Upstream input/output rsv: reserve, prov: provision, rel: release, cncl: cancel.rq : request,.cf: confirm, gr: granted, ng: not granted *: for input, receive from all children for output, send to all children &: received one or more rcv.ng Note: here, downstream agent is assumed to return cncl.cf (or ignore cncl.rq for the orange case) if there is no corresponding reservation. Not necessary?

11. Combination of Arlington and Berkeley state machines

12. NSA RA SM PA SM RA SM NSA PA SM NSA RA SM PA SM NRM UR AG UP AG Example: NS with Ultimate Requester(UR), Ultimate Provider(UP) and Aggregator (AG)

13. Initial Schedu led Idle In Service Auto Start Termin ated >provision_start (start_time) (provision) <provision_complete >provision_start (provision) <provision_complete >reserve_start, (reservation ok) <reserve_ok >release_start (release) <release_complete (start_time)(end_time) (cancel) Input Output blue : an input/output event which is not an NSI message >: Downstream input/output <: Upstream input/output (event): internal event start_time: start time timer event end_time: end time timer event,: “all” condition Sample Ultimate Provider function >reserve_start, (reservation ng) <reserve_ng (end_time) (release) (cancel) >cancel_start (cancel) <cancel_complete Any state Not necessary?

14. Reservi ng Reserv ed In Service Provisi oning Releasi ng Initial >cancel_start >cancel_start* <cancel_complete* <cancel_complete Termin ated Any state Canceli ng >provision_request >provision_request* <provision_complete* <provision_complete <release_complete* <release_complete >release_request >release_request* <reserve_complete* <reserve_complete <reserve_ng& <reserve_ng >cancel_start* >reserve_request >reserve_request* Sample Aggregator function Input Output blue : an input/output event which is not an NSI message >: Downstream input/output <: Upstream input/output *: for input, receive from all children for output, send to all children &: received one or more reserve_ng Note: here, downstream agent is assumed to return cancel_complete (or ignore cancel_request for the orange case) if there is no corresponding reservation. Not necessary?