Assuring QoS Guarantees for Heterogeneous Services in RINA Networks with ΔQ

Gaixas, Sergio Leon; Perelló, Jordi; Careglio, Davide; Grasa, Eduard; Tarzán, Miquel; Davies, Neil; Thompson, Peter

doi:10.1109/cloudcom.2016.0101

Cited by 12 publications

(11 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From the perspective of a user, a perfect system would deliver the desired outcome without error, failure or delay, whereas real systems always fall short of this; we can say that the quality of their response is attenuated relative to the ideal. We denote this 'quality attenuation' by the symbol ∆Q and reformulate the problem of managing performance as one of maintaining suitable bounds on ∆Q [16]. This is an important conceptual shift because 'performance' may appear to be something that can be increased arbitrarily, whereas ∆Q (rather like noise) is something that may be minimised but that can never be completely eliminated.…”

Section: Outcome Diagrams and Outcome Expressionsmentioning

confidence: 99%

Mind Your Outcomes: The ∆Q approach to Quality-Centric Systems Development and Its Application to a Blockchain Case-Study

HAERI¹,

Thompson²,

Davies³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

This paper directly addresses a long-standing issue that affects the development of many1 complex distributed software systems: how to establish quickly, cheaply, and reliably whether2 they can deliver their intended performance before expending significant time, effort and money on3 detailed design and implementation. We describe ∆QSD, a novel metrics-based and quality-centric4 paradigm that uses formalised outcome diagrams to explore the performance consequences of design5 decisions, as a performance blueprint of the system. The distinctive feature of outcome diagrams is6 that they capture the essential observational properties of the system, independent of the details of7 system structure and behaviour. The ∆QSD paradigm derives bounds on performance expressed as8 probability distributions encompassing all possible executions of the system. The ∆QSD paradigm9 is both effective and generic: it allows values from various sources to be combined in a rigorous10 way, so that approximate results can be obtained quickly and subsequently refined. ∆QSD has been11 successfully used by Predictable Network Solutions for consultancy on large-scale applications in a12 number of industries, including telecommunications, avionics, and space and defence, resulting in13 cumulative savings worth billions of US dollars. The paper outlines the ∆QSD paradigm, describes14 its formal underpinnings, and illustrates its use via a topical real-world example taken from the15 blockchain/cryptocurrency domain. ∆QSD has enabled challenging throughput targets to be met for16 a globally distributed blockchain operating on the public internet.

show abstract

Section: Outcome Diagrams and Outcome Expressionsmentioning

confidence: 99%

Mind Your Outcomes: The ∆Q approach to Quality-Centric Systems Development and Its Application to a Blockchain Case-Study

HAERI¹,

Thompson²,

Davies³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…From the perspective of a user, a perfect system would deliver the desired outcome without error, failure or delay, whereas real systems always fall short of this; we can say that the quality of their response is attenuated relative to the ideal. We denote this 'quality attenuation' by the symbol ∆Q and reformulate the problem of managing performance as one of maintaining suitable bounds on ∆Q [15]. This is an important conceptual shift because 'performance' may appear to be something that can be increased arbitrarily, whereas ∆Q (rather like noise) is something that may be minimised but that can never be completely eliminated.…”

Section: Quality Attenuation (∆Q)mentioning

confidence: 99%

Mind Your Outcomes: Quality-Centric Systems Development

HAERI¹,

Thompson²,

Davies³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

This paper directly addresses a critical issue that affects the development of many complex distributed software systems: how to establish quickly, cheaply and reliably whether they will deliver their intended performance before expending significant time, effort and money on detailed design and implementation. We describe ΔQSD, a novel metrics-based and quality-centric paradigm that uses formalised outcome diagrams to explore the performance consequences of design decisions, as a performance blueprint of the system. The ΔQSD paradigm is both effective and generic: it allows values from various sources to be combined in a rigorous way, so that approximate results can be obtained quickly and subsequently refined. ΔQSD has been successfully used by Predictable Network Solutions for consultancy on large-scale applications in a number of industries, including telecommunications, avionics, and space and defence, resulting in cumulative savings of $Bs. The paper outlines the ΔQSD paradigm, describes its formal underpinnings, and illustrates its use via a topical real-world example taken from the blockchain/cryptocurrency domain, where application of this approach enabled an advanced distributed proof-of-stake system to meet challenging throughput targets.

show abstract

“…We used simulations to verify that our peer selection algorithm, which takes decisions locally, leads to suitable network topologies globally. The peer selection takes into account both the number of hops to disperse information and the network distance of each hop, relying on local measurements of the network distance to available peers in the ΔQ framework [Ree03,DHT99b,LGPC+16,DHT99a,DHST99].…”

Section: Approach(es) Taken At Iohkmentioning

confidence: 99%

Flexible Formality Practical Experience with Agile Formal Methods

Kant

Hammond

Coutts

et al. 2020

Lecture Notes in Computer Science

Self Cite

View full text Add to dashboard Cite

Agile software development and Formal Methods are traditionally seen as being in conflict. From an Agile perspective, there is pressure to deliver quickly, building vertical prototypes and doing many iterations/sprints, refining the requirements; from a Formal Methods perspective, there is pressure to deliver correctly and any change in requirements often necessitates changes in the formal specification and might even impact all arguments of correctness. Over the years, the need to "be agile" has become a kind of mantra in software development management, and there is a prevalent prejudice that using formal methods was an impediment to being agile. In this paper, we contribute to the refutation of this stereotype, by providing a real-world example of using good practices from formal methods and agile software engineering to deliver software that is simultaneously reliable, effective, testable, and that can also be iterated and delivered rapidly. We thus present how a lightweight software engineering methodology, drawing from appropriate formal methods techniques and providing the benefits of agile software development, can look like. Our methodology is informed and motivated by practical experience. We have devised and adapted it in the light of experience in delivering a large-scale software system that needs to meet complex real-world requirements: the Cardano blockchain and its cryptocurrency ada. The cryptocurrency domain is a rather new application area for which no clear engineering habit exists, so it is fitting well for agile methods.

show abstract

Assuring QoS Guarantees for Heterogeneous Services in RINA Networks with ΔQ

Cited by 12 publications

References 4 publications

Mind Your Outcomes: The ∆Q approach to Quality-Centric Systems Development and Its Application to a Blockchain Case-Study

Mind Your Outcomes: The ∆Q approach to Quality-Centric Systems Development and Its Application to a Blockchain Case-Study

Mind Your Outcomes: Quality-Centric Systems Development

Flexible Formality Practical Experience with Agile Formal Methods

Contact Info

Product

Resources

About