title: An algorithmic approach to OpenFlow ruleset transformation

authors: Sanger, Richard

abstract: In an ideal development cycle for an OpenFlow application, a developer designs a pipeline to suit their application's needs and installs rules to that pipeline. Their application will run on any OpenFlow switch, whether software or hardware based. A network operator deploying this application would assess their network's requirements and purchase OpenFlow hardware to meet these requirements; such as bandwidth, port density, and flow table size. In reality, this level of interoperability does not exist as many OpenFlow switches are built on a fixed-function pipeline. Fixed-function pipelines limit the matches and actions available to rules depending on the table, but in doing so make more efficient use of expensive hardware resources such as TCAM.

This thesis investigates improving OpenFlow device interoperability by developing a method to rewrite existing rulesets to new complex fixed-function pipelines. Additionally, this thesis developed the tools to assess and verify the interoperability and equivalence of OpenFlow rulesets and pipelines. 

This thesis developed a library and tools for working with descriptions of fixed-function pipelines, specifically, the Table Type Pattern description. This library provides a method to check if an existing ruleset is compatible with a new pipeline. Additionally, this thesis designed and implemented a pragmatic approach to compare if the forwarding behaviour of two OpenFlow 1.3 rulesets is equivalent. Equivalence checking provides a tool to verify that an OpenFlow application rewritten to program a new pipeline maintains the correct forwarding behaviour.

Finally, this thesis investigates the problem of algorithmically rewriting an existing OpenFlow ruleset, programmed by an existing application, to fit a different fixed-function pipeline. Solving this problem allows an OpenFlow application to be written once and run on any OpenFlow switch. This research aimed to solve this problem in a comprehensive manner that did not rely on the target pipeline supporting features such as OpenFlow metadata. This thesis developed and implemented a general method to convert an OpenFlow 1.3 to a complex constrained fixed-function.

text: An algorithmic approach to OpenFlow ruleset transformation In an ideal development cycle for an OpenFlow application, a developer designs a pipeline to suit their application's needs and installs rules to that pipeline. Their application will run on any OpenFlow switch, whether software or hardware based. A network operator deploying this application would assess their network's requirements and purchase OpenFlow hardware to meet these requirements; such as bandwidth, port density, and flow table size. In reality, this level of interoperability does not exist as many OpenFlow switches are built on a fixed-function pipeline. Fixed-function pipelines limit the matches and actions available to rules depending on the table, but in doing so make more efficient use of expensive hardware resources such as TCAM.

This thesis investigates improving OpenFlow device interoperability by developing a method to rewrite existing rulesets to new complex fixed-function pipelines. Additionally, this thesis developed the tools to assess and verify the interoperability and equivalence of OpenFlow rulesets and pipelines. 

This thesis developed a library and tools for working with descriptions of fixed-function pipelines, specifically, the Table Type Pattern description. This library provides a method to check if an existing ruleset is compatible with a new pipeline. Additionally, this thesis designed and implemented a pragmatic approach to compare if the forwarding behaviour of two OpenFlow 1.3 rulesets is equivalent. Equivalence checking provides a tool to verify that an OpenFlow application rewritten to program a new pipeline maintains the correct forwarding behaviour.

Finally, this thesis investigates the problem of algorithmically rewriting an existing OpenFlow ruleset, programmed by an existing application, to fit a different fixed-function pipeline. Solving this problem allows an OpenFlow application to be written once and run on any OpenFlow switch. This research aimed to solve this problem in a comprehensive manner that did not rely on the target pipeline supporting features such as OpenFlow metadata. This thesis developed and implemented a general method to convert an OpenFlow 1.3 to a complex constrained fixed-function.

year: 2020

title: Mental Health Service Provision for the People of Cambridge: Are services facilitating recovery?

authors: Cleland, Hannah Nicole

subjects: mental health services

abstract: The purpose of the present research was to investigate consumer perspectives of mental health service provision in Cambridge and whether services were helpful in facilitating recovery. Cambridge is a small township in the Waikato region, approximately twenty-five kilometers south-east of Hamilton. The study aimed to: gain an understanding of consumers’ interpretations of recovery; identify consumer perspectives of service delivery in Cambridge; assess whether services in Cambridge are working from a recovery ethos; and determine how consumers’ think service delivery could be improved. Interviews with 14 consumers of mental health services were completed. The key findings of this study suggest that the mental health needs of Cambridge consumer’s were not being met. More specifically, consumers’ who had severe or mild mental illness were reasonably happy with service delivery. However, consumers whose mental illness impacted their life considerably, yet their symptoms were not deemed severe enough to access public services, identified significant discrepancies between service provision and recovery facilitation.

text: Mental Health Service Provision for the People of Cambridge: Are services facilitating recovery? The purpose of the present research was to investigate consumer perspectives of mental health service provision in Cambridge and whether services were helpful in facilitating recovery. Cambridge is a small township in the Waikato region, approximately twenty-five kilometers south-east of Hamilton. The study aimed to: gain an understanding of consumers’ interpretations of recovery; identify consumer perspectives of service delivery in Cambridge; assess whether services in Cambridge are working from a recovery ethos; and determine how consumers’ think service delivery could be improved. Interviews with 14 consumers of mental health services were completed. The key findings of this study suggest that the mental health needs of Cambridge consumer’s were not being met. More specifically, consumers’ who had severe or mild mental illness were reasonably happy with service delivery. However, consumers whose mental illness impacted their life considerably, yet their symptoms were not deemed severe enough to access public services, identified significant discrepancies between service provision and recovery facilitation.

year: 2010

title: 'The voices caused him to become porangi': Maori Patients in the Auckland Lunatic Asylum, 1860-1900

authors: Burke, Lorelle J.

abstract: Histories of the asylum have raised a number of important questions about the way 'race' intersects along colonial, medical and legal boundaries. The experience of Maori patients at the Auckland Lunatic Asylum was a site where colonial attitudes towards 'race' were played out along such lines. By employing 'race' as a category of historical analysis, one can attempt to investigate how the asylum processes in Aotearoa/New Zealand exemplified the question of 'race' in an effort to make more visible the experiences, attitudes and responses of Maori asylum patients. 
This thesis examines colonial 'madness' by investigating the experiences of Maori patients at the Auckland Lunatic Asylum from 1860-1900. Using patient case records from this period this thesis interrogates the experiences of Maori patients in a colonial asylum, away from their whanau, communities, and tribal networks; what factors contributed to this, and how colonial attitudes towards these patients were acted out. The first chapter therefore, explores the 'medico-legal' management of these Maori patients, followed in Chapter Two by a broad overview of the Maori patients themselves. Chapter Three analyses the case records in more depth illustrating the complex interplay between 'race', gender, 'whiteness' and culture. Chapter Four looks at the way Maori dealt with the insane away from European institutions such as the asylum, emphasising how colonial histories of medicine now paying attention to Indigenous peoples in their context, and to medical pluralism, which reflects European models on one hand and on the other, Maori modes. 
In considering Maori patients, this thesis reflects on the very 'human experience' that can be revealed by using asylum case files, and what such sources may suggest about 'race' as an implicit part of colonial asylum administration. More widely, the paper also reflects on colonisation, Maori and the asylum, and the ways in which Maori used the asylum.

text: 'The voices caused him to become porangi': Maori Patients in the Auckland Lunatic Asylum, 1860-1900 Histories of the asylum have raised a number of important questions about the way 'race' intersects along colonial, medical and legal boundaries. The experience of Maori patients at the Auckland Lunatic Asylum was a site where colonial attitudes towards 'race' were played out along such lines. By employing 'race' as a category of historical analysis, one can attempt to investigate how the asylum processes in Aotearoa/New Zealand exemplified the question of 'race' in an effort to make more visible the experiences, attitudes and responses of Maori asylum patients. 
This thesis examines colonial 'madness' by investigating the experiences of Maori patients at the Auckland Lunatic Asylum from 1860-1900. Using patient case records from this period this thesis interrogates the experiences of Maori patients in a colonial asylum, away from their whanau, communities, and tribal networks; what factors contributed to this, and how colonial attitudes towards these patients were acted out. The first chapter therefore, explores the 'medico-legal' management of these Maori patients, followed in Chapter Two by a broad overview of the Maori patients themselves. Chapter Three analyses the case records in more depth illustrating the complex interplay between 'race', gender, 'whiteness' and culture. Chapter Four looks at the way Maori dealt with the insane away from European institutions such as the asylum, emphasising how colonial histories of medicine now paying attention to Indigenous peoples in their context, and to medical pluralism, which reflects European models on one hand and on the other, Maori modes. 
In considering Maori patients, this thesis reflects on the very 'human experience' that can be revealed by using asylum case files, and what such sources may suggest about 'race' as an implicit part of colonial asylum administration. More widely, the paper also reflects on colonisation, Maori and the asylum, and the ways in which Maori used the asylum.

year: 2006