Improving Temporal-Awareness of WS-Agreement
Abstract
WS-Agreement (WS-Ag) is a proposed recommendation of the Open Grid Forum that provides a schema to describe SLAs and a protocol to create them based on a mechanism of templates. However, although it identifies the necessity of specifying temporal-aware agreement terms (e.g. the response time is 30 ms from 8:00h to 17:00h and 15 ms from 17:00h to 8:00h), to the best of our knowledge, there are no existing proposals that deal with that necessity. We propose an extension that gives WS-Ag support to temporality. This allows describing expressive validity periods such as those composed by several periodic or non-periodic intervals and it applies not only to the agreement terms themselves but also to other parts of WS-Ag such as creation constraints and preferences about the service properties. in addition, in this paper we propose a preference XML schema to describe preferences over any set of service properties using any kind of utility function. in further research we will study a concrete specification for those utility functions.
Full text
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%$$ 4 ;< AgreementTemplate GlobalPeriod GuaranteeTerm1 ∧GuaranteeTerm2 MoreMTBR LocalPeriod GuaranteeTerm1: MTBR ≥ 20 2 4 6 8 10 12 14 16 18 20 22 Daily GMT +1 From Oct 01/2007 to Dec 30/2007 From Oct 01/2007 to Dec 30/2007 Mon-Sat (Weekly) Sunday (Weekly) From Oct 01/2007 to Dec 30/2007 From Oct 01/2007 to Dec 30/2007 Mon-Fri (Weekly) Sat-Sund (Weekly) From Oct 01/2007 to Dec 30/2007 Mon-Fri (Weekly) LessMTBR LocalPeriod GuaranteeTerm2: MTBR ≥ 1 *, @ A ( 4 8 " # = 3 % 8 ' 8 @0 ! 6E4 3 % %'%% ' % ! .@ 4 ( " #= 3 # 3 4 %# " 8 8 ## 3&4 % ! %# %= )-+ 8 % 3&%4 ! ! ( %# # ( ) " % ! 3"4 % ! :(+9 ).+ 3 4 % ! %# # ( A )-+ 8 '%# ! ( $ ! (% ' % & ( % " # 3L!"(4 " C #! 3EM*4 % 78 #! :( 8 % 8% # !" ? 3!4 % " ! # % 6 ! 2 )-+ # % 8 5 ! ## ( #! ).+ ( % ( "! # % " # 6! 8 " ! "8" & " " ! 8 " % ! ## 8 ## ' % ! '#( #! :( "( 3%EM4 % ## #!
'. &' %$# Agreement Template Terms Compositor Context Name <ServiceDescriptionTerm> <Request> </Request> <Algorithm> </Algorithm> <MTBR> </MTBR> </ServiceDescriptionTerm> <ServiceProperties> <Variables> <Variable name=”MTBR MTBR” metric=”seconds”> <Location> // //ServiceDescriptionTerm ServiceDescriptionTerm/MTBR /MTBR </Location> <Variable> <Variable name=”Algorithm Algorithm”> <Location> // //ServiceDescriptionTerm ServiceDescriptionTerm/Algorithm /Algorithm </Location> <Variable> <Variables> </ServiceProperties> <ServiceProvider>responder</ServiceProvider> … < <GlobalPeriod GlobalPeriod> > <! <!-- --Global Global Period Period Definition Definition-- --> > </ </GlobalPeriod GlobalPeriod> > <All> … Creation Constraints <Item Name=”AlgorithmAllowed AlgorithmAllowed”> <Location> //ServiceDescriptionTerm/Algorithm </Location> <ItemConstraint> <xs:restriction base="xs:string"> <xs:enumeration value=“Dijkstra Dijkstra" /> <xs:enumeration value=“Knapsack Knapsack" /> <xs:enumeration value=“Kruskal Kruskal" /> </xs:restriction> </ItemConstraint> </Item> </All> <Item Name=”MTBRAllowed MTBRAllowed”> <Location> //ServiceDescriptionTerm/MTBR </Location> <ItemConstraint> <restriction base="xsd:positiveInteger"> <xsd:minInclusive value=“01 01"/> </xsd:restriction> </ItemConstraint> </Item> <GuaranteeTerm Obligated=“ServiceProvider”...> < <QualifyingCondition QualifyingCondition> > <! <!-- --MoreMTBR MoreMTBR Period Period Definition Definition-- --> > </ </QualifyingCondition QualifyingCondition> > <SLO>”MTBR MTBR ≥ ≥20” 20”</SLO> <BusinessValueList> <CustomBussinessValue> <VariableReference>Algorithm Algorithm</…> <UtilityFunction>F F 1 1 (U) (U)</…> <VariableReference>MTBR MTBR</…> <UtilityFunction>F F 3 3 (U) (U)</…> </CustomBussinessValue> </BusinessValueList> </GuaranteeTerm> <GuaranteeTerm Obligated=“ServiceProvider”...> < <QualifyingCondition QualifyingCondition> > <! <!-- --LessMTBR LessMTBR Period Period Definition Definition-- --> > </ </QualifyingCondition QualifyingCondition> > <SLO>”MTBR MTBR ≥ ≥1 1” ”</SLO> <BusinessValueList> <CustomBussinessValue> <VariableReference>Algorithm Algorithm</…> <UtilityFunction>F F 2 2 (U) (U)</…> <VariableReference>MTBR MTBR</…> <UtilityFunction>F F 4 4 (U) (U)</…> </CustomBussinessValue> </BusinessValueList> </GuaranteeTerm> ! ' Agreement Offer Terms Compositor Context Name <ServiceProvider>responder</ServiceProvider> … < <GlobalPeriod GlobalPeriod> > <! <!-- --Global Global Period Period Definition Definition-- --> > </ </GlobalPeriod GlobalPeriod> > <All> … </All> <ServiceProperties…> … </ServiceProperties> < <ExactlyOne ExactlyOne> > <All> <All> <ServiceDescriptionTerm…> <Request>Sample.txt</Request> < <Algorithm Algorithm> >Knapsack Knapsack</ </Algorithm Algorithm> > <MTBR>20</MTBR> <MTBR>20</MTBR> </ServiceDescriptionTerm> <GuaranteeTerm Obligated=“ServiceProvider”...> < <QualifyingCondition QualifyingCondition> > <! <!-- --MoreMTBR MoreMTBR Period Period Definition Definition-- --> > </ </QualifyingCondition QualifyingCondition> > <SLO>”MTBR MTBR ≥ ≥20 20” ”</SLO> …<!--The same BussinessValue and Utility--> </GuaranteeTerm> </All> </All> <All> <All> <ServiceDescriptionTerm…> <Request>Sample.txt</Request> < <Algorithm Algorithm> >Knapsack Knapsack</ </Algorithm Algorithm> > <MTBR>1</MTBR> <MTBR>1</MTBR> </ServiceDescriptionTerm> <GuaranteeTerm Obligated=“ServiceProvider”...> < <QualifyingCondition QualifyingCondition> > <! <!-- --LessMTBR LessMTBR Period Period Definition Definition-- --> > </ </QualifyingCondition QualifyingCondition> > <SLO>”MTBR MTBR ≥ ≥1 1” ”</SLO> …<!--The same BussinessValue and Utility--> </GuaranteeTerm> </All> </All> </ </ExactlyOne ExactlyOne> > ,! ')> < <GlobalPeriod GlobalPeriod> > < <Periodical Periodical frequency frequency=” =”1.0 1.0” ” frequencyMe frequencyMet tric ric=” =”Hours Hours” ” repetitions repetitions=”13.0”> =”13.0”> < <Interval Interval init init=”2007 =”2007- -10 10- -01T00:00:00+01:00” 01T00:00:00+01:00” duration duration=” =”167.0 167.0” ” durationMetric durationMetric=” =”Hours Hours”/> ”/> </ </Periodical Periodical> > </ </GlobalPeriod GlobalPeriod> > From Monday 0:00 to Sunday 23:00 From 10/01/2007 to 12/30/2007 (13 weeks) < <Periodical Periodical frequency frequency=”62.0” =”62.0” frequencyMe frequencyMet tric ric=” =”Hours Hours” ” repetitions repetitions=”13.0”> =”13.0”> < <Periodical Periodical frequency frequency=” =”14.0 14.0” ” frequencyMe frequencyMet tric ric=” =”Hours Hours” ” repetitions repetitions=”5.0”> =”5.0”> < <Interval Interval init init=”2007 =”2007- -10 10- -01T08:00:00+01:00” 01T08:00:00+01:00” duration duration=” =”10.0 10.0” ” durationMetric durationMetric=” =”Hours Hours”/> ”/> </ </Periodical Periodical> > </ </Periodical Periodical> >From 8:00 to 18:00 From 18:00 to 8:00 From Monday to Friday More MTBR Period From 18:00 to 24:00 + Weekend + From 0:00 to 8:00 Weekend < <Periodical Periodical frequency frequency=”0.0” =”0.0” frequencyMe frequencyMet tric ric=” =”Seconds Seconds” ” repetitions repetitions=”13.0”> =”13.0”> < <Disjoint Disjoint op op=“ =“And And”> ”> < <Periodical Periodical frequency frequency=” =”57601.00 57601.00” ” frequencyMe frequencyMet tric ric=” =”Seconds Seconds” ” repetitions repetitions=”5.0”> =”5.0”> < <Interval Interval init init=”2007 =”2007- -10 10- -01T00:00:00+01:00” 01T00:00:00+01:00” duration duration=” =”28799.00 28799.00” ” durationMetric durationMetric=” =”Seconds Seconds”/> ”/> </ </Periodical Periodical> > < <Periodical Periodical frequency frequency=” =”64801.00 64801.00” ” frequencyMe frequencyMet tric ric=“ =“Seconds Seconds” ” repetitions repetitions=”5.0”> =”5.0”> < <Interval Interval init init=”2007 =”2007- -10 10- -01T18:00:01+01:00” 01T18:00:01+01:00” duration duration=” =”21599.00 21599.00” ” durationMetric durationMetric=” =”Seconds Seconds”/> ”/> </ </Periodical Periodical> > < <Interval Interval init init=”2007 =”2007- -10 10- -06T00:00:00+01:00” 06T00:00:00+01:00” duration duration=” =”2.0 2.0” ” durationMetric durationMetric=” =”Days Days”/> ”/> </ </Disjoint Disjoint> > </ </Periodical Periodical> > From 0:00:00 to 7:59:59 in Seconds From 7:59:59 to 24:00:00 in Seconds From 18:00:01 to 24:00:00 in Seconds From 0:00:00 to 18:00:01 in Seconds Less MTBR Period Global Period ! 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