title: High precision timing in passive measurements of data networks

authors: Donnelly, Stephen F.

abstract: Understanding, predicting, and improving network behaviour under a wide range of conditions requires accurate models of protocols, network devices, and link properties. Accurate models of the component parts comprising complex networks allows the plausible simulation of networks in other configurations, or under different loads. These models must be constructed on a solid foundation of reliable and accurate data taken from measurements of relevant facets of actual network behaviour.
As network link speeds increase, it is argued that traditional network measurement techniques based primarily on software time-stamping and capture of packets will not scale to the required performance levels. Problems examined include the difficulty of gaining access to high speed network media to perform measurements, the insufficient resolution of time-stamping clocks for capturing fine detail in packet arrival times, the lack of synchronisation of clocks to global standards, the high and variable latency between packet arrival and time-stamping, and the occurrence of packet loss within the measurement system. A set of design requirements are developed to address these issues, especially in high-speed network measurement systems.
A group at the University of Waikato including myself has developed a series of hardware based passive network measurement systems called ‘Dags’. Dags use re-programmable hardware and embedded processors to provide globally synchronised, low latency, reliable time-stamping of all packet arrivals on high-speed network links with sub-hundred nanosecond resolution. Packet loss within the measurement system is minimised by providing sufficient bandwidth throughout for worst case loads and buffering to allow for contention over shared resources. Any occurrence of packet loss despite these measures is reported, allowing the invalidation of portions of the dataset if necessary. I was responsible for writing both the interactive monitor and network measurement code executed by the Dag’s embedded processor, developing a Linux device driver including the software part of the ‘DUCK’ clock synchronisation system, and other ancillary software.
It is shown that the accuracy and reliability of the Dag measurement system allows confidence that rare, unusual or unexpected features found in its measurements are genuine and do not simply reflect artifacts of the measurement equipment. With the use of a global clock reference such as the Global Positioning System, synchronised multi-point passive measurements can be made over large geographical distances. Both of these features are exploited to perform calibration measurements of RIPE NCC’s Test Traffic Measurement System for One-way-Delay over the Internet between New Zealand and the Netherlands. Accurate single point passive measurement is used to determine error distributions in Round Trip Times as measured by NLANR’s AMP project.
The high resolution afforded by the Dag measurement system also allows the examination of the forwarding behaviour of individual network devices such as routers and firewalls at fine time-scales. The effects of load, queueing parameters, and pauses in packet forwarding can be measured, along with the impact on the network traffic itself. This facility is demonstrated by instrumenting routing equipment and a firewall which provide Internet connectivity to the University of Auckland, providing passive measurements of forwarding delay through the equipment.both the interactive monitor and network measurement code executed by the Dag’s embedded processor, developing a Linux device driver including the software part of the ‘DUCK’ clock synchronisation system, and other ancillary software. It is shown that the accuracy and reliability of the Dag measurement system allows confidence that rare, unusual or unexpected features found in its measurements are genuine and do not simply reflect artifacts of the measurement equipment. With the use of a global clock reference such as the Global Positioning System, synchronised multi-point passive measurements can be made over large geographical distances. Both of these features are exploited to perform calibration measurements of RIPE NCC’s Test Traffic Measurement System for One-way-Delay over the Internet between New Zealand and the Netherlands. Accurate single point passive measurement is used to determine error distributions in Round Trip Times as measured by NLANR’s AMP project.
The high resolution afforded by the Dag measurement system also allows the examination of the forwarding behaviour of individual network devices such as routers and firewalls at fine time-scales. The effects of load, queueing parameters, and pauses in packet forwarding can be measured, along with the impact on the network traffic itself. This facility is demonstrated by instrumenting routing equipment and a firewall which provide Internet connectivity to the University of Auckland, providing passive measurements of forwarding delay through the equipment.

text: High precision timing in passive measurements of data networks Understanding, predicting, and improving network behaviour under a wide range of conditions requires accurate models of protocols, network devices, and link properties. Accurate models of the component parts comprising complex networks allows the plausible simulation of networks in other configurations, or under different loads. These models must be constructed on a solid foundation of reliable and accurate data taken from measurements of relevant facets of actual network behaviour.
As network link speeds increase, it is argued that traditional network measurement techniques based primarily on software time-stamping and capture of packets will not scale to the required performance levels. Problems examined include the difficulty of gaining access to high speed network media to perform measurements, the insufficient resolution of time-stamping clocks for capturing fine detail in packet arrival times, the lack of synchronisation of clocks to global standards, the high and variable latency between packet arrival and time-stamping, and the occurrence of packet loss within the measurement system. A set of design requirements are developed to address these issues, especially in high-speed network measurement systems.
A group at the University of Waikato including myself has developed a series of hardware based passive network measurement systems called ‘Dags’. Dags use re-programmable hardware and embedded processors to provide globally synchronised, low latency, reliable time-stamping of all packet arrivals on high-speed network links with sub-hundred nanosecond resolution. Packet loss within the measurement system is minimised by providing sufficient bandwidth throughout for worst case loads and buffering to allow for contention over shared resources. Any occurrence of packet loss despite these measures is reported, allowing the invalidation of portions of the dataset if necessary. I was responsible for writing both the interactive monitor and network measurement code executed by the Dag’s embedded processor, developing a Linux device driver including the software part of the ‘DUCK’ clock synchronisation system, and other ancillary software.
It is shown that the accuracy and reliability of the Dag measurement system allows confidence that rare, unusual or unexpected features found in its measurements are genuine and do not simply reflect artifacts of the measurement equipment. With the use of a global clock reference such as the Global Positioning System, synchronised multi-point passive measurements can be made over large geographical distances. Both of these features are exploited to perform calibration measurements of RIPE NCC’s Test Traffic Measurement System for One-way-Delay over the Internet between New Zealand and the Netherlands. Accurate single point passive measurement is used to determine error distributions in Round Trip Times as measured by NLANR’s AMP project.
The high resolution afforded by the Dag measurement system also allows the examination of the forwarding behaviour of individual network devices such as routers and firewalls at fine time-scales. The effects of load, queueing parameters, and pauses in packet forwarding can be measured, along with the impact on the network traffic itself. This facility is demonstrated by instrumenting routing equipment and a firewall which provide Internet connectivity to the University of Auckland, providing passive measurements of forwarding delay through the equipment.both the interactive monitor and network measurement code executed by the Dag’s embedded processor, developing a Linux device driver including the software part of the ‘DUCK’ clock synchronisation system, and other ancillary software. It is shown that the accuracy and reliability of the Dag measurement system allows confidence that rare, unusual or unexpected features found in its measurements are genuine and do not simply reflect artifacts of the measurement equipment. With the use of a global clock reference such as the Global Positioning System, synchronised multi-point passive measurements can be made over large geographical distances. Both of these features are exploited to perform calibration measurements of RIPE NCC’s Test Traffic Measurement System for One-way-Delay over the Internet between New Zealand and the Netherlands. Accurate single point passive measurement is used to determine error distributions in Round Trip Times as measured by NLANR’s AMP project.
The high resolution afforded by the Dag measurement system also allows the examination of the forwarding behaviour of individual network devices such as routers and firewalls at fine time-scales. The effects of load, queueing parameters, and pauses in packet forwarding can be measured, along with the impact on the network traffic itself. This facility is demonstrated by instrumenting routing equipment and a firewall which provide Internet connectivity to the University of Auckland, providing passive measurements of forwarding delay through the equipment.

year: 2002

title: The effects of foreign direct investment on domestic firms: The case of Vietnam

authors: Ha, Van Thi Cam

subjects: Foreign direct investment

abstract: Thanks to the economic reform after the launch of “Doi moi” in 1986, Vietnam has made significant gains and has transformed from an economically poor country in the 1980-90s towards a middle-income country by the 2010s. A dynamic market deeply integrated into the global economy has helped pave the way for foreign investment inflows to Vietnam. While it is clear that foreign direct investment plays a crucial role in the economy as a whole, the debate continues on whether foreign direct investment has positive or negative effects on domestic firms. In developing countries, foreign investment can be supportive to local enterprises where the former provides technological advantages that are beneficial. However, there are examples of where foreign presence negatively impacts on the development of local firms if they do not have adequate resources to absorb spillovers. This thesis examines whether the presence of foreign direct investment contributes to the development of Vietnamese firms from different angles including productivity, export activity, R&D and innovation and investment during the 2010-15 period. The thesis comprises four papers.
The first paper examines the impacts of foreign presence on domestic enterprise productivity within and between industries through horizontal and vertical channels. Panel data models are employed to investigate the linkage between foreign investment and local firm total factor productivity. The results indicate the presence of positive spillovers from foreign investment in downstream sectors to domestic firm productivity in upstream sectors through backward linkages, while a negative impact is found in the same sectors through horizontal linkages.
In the second paper, Heckman selection estimation is employed to investigate whether foreign investment has any influence on the exporting activity of domestic firms. The results suggest that while foreign investment in downstream sectors is found to encourage the export decision of local firms in the same and upstream sectors through horizontal and backward linkages, the export intensity of local firms only benefits from backward linkages. The linkages between exporting activity of local firms and the presence of foreign investment appears to be different when comparing low- and high-tech firms. 
While it is argued that foreign investment in a host country can encourage domestic firms to invest in R&D and innovation, there are few studies that consider the case of Vietnam. The third paper of the thesis fills this gap. The results suggest that there is a weak positive association between foreign investment and local firms R&D activity and innovation through forward linkages, while there is no significant evidence to support the view that multinational enterprises help improve local firms R&D behaviour through horizontal and backward linkages. 
The final paper in this thesis investigates the possibility of crowding-effects from foreign investment to local investment. System General Method of Moments estimation is employed to a sector-level balanced panel dataset to account for dynamic effects.  The results indicate that foreign investment significantly encourages domestic investment, and export-oriented sectors appear to be more sensitive to the impact from multinational investment.

text: The effects of foreign direct investment on domestic firms: The case of Vietnam Thanks to the economic reform after the launch of “Doi moi” in 1986, Vietnam has made significant gains and has transformed from an economically poor country in the 1980-90s towards a middle-income country by the 2010s. A dynamic market deeply integrated into the global economy has helped pave the way for foreign investment inflows to Vietnam. While it is clear that foreign direct investment plays a crucial role in the economy as a whole, the debate continues on whether foreign direct investment has positive or negative effects on domestic firms. In developing countries, foreign investment can be supportive to local enterprises where the former provides technological advantages that are beneficial. However, there are examples of where foreign presence negatively impacts on the development of local firms if they do not have adequate resources to absorb spillovers. This thesis examines whether the presence of foreign direct investment contributes to the development of Vietnamese firms from different angles including productivity, export activity, R&D and innovation and investment during the 2010-15 period. The thesis comprises four papers.
The first paper examines the impacts of foreign presence on domestic enterprise productivity within and between industries through horizontal and vertical channels. Panel data models are employed to investigate the linkage between foreign investment and local firm total factor productivity. The results indicate the presence of positive spillovers from foreign investment in downstream sectors to domestic firm productivity in upstream sectors through backward linkages, while a negative impact is found in the same sectors through horizontal linkages.
In the second paper, Heckman selection estimation is employed to investigate whether foreign investment has any influence on the exporting activity of domestic firms. The results suggest that while foreign investment in downstream sectors is found to encourage the export decision of local firms in the same and upstream sectors through horizontal and backward linkages, the export intensity of local firms only benefits from backward linkages. The linkages between exporting activity of local firms and the presence of foreign investment appears to be different when comparing low- and high-tech firms. 
While it is argued that foreign investment in a host country can encourage domestic firms to invest in R&D and innovation, there are few studies that consider the case of Vietnam. The third paper of the thesis fills this gap. The results suggest that there is a weak positive association between foreign investment and local firms R&D activity and innovation through forward linkages, while there is no significant evidence to support the view that multinational enterprises help improve local firms R&D behaviour through horizontal and backward linkages. 
The final paper in this thesis investigates the possibility of crowding-effects from foreign investment to local investment. System General Method of Moments estimation is employed to a sector-level balanced panel dataset to account for dynamic effects.  The results indicate that foreign investment significantly encourages domestic investment, and export-oriented sectors appear to be more sensitive to the impact from multinational investment.

year: 2021

title: Succeeding as Māori: Māori students’ views on our Stepping Up to the Ka Hikitia Challenge

authors: Berryman, Mere

subjects: Ka Hikitia

abstract: This paper examines the vision and intent of New Zealand’s Māori education policy, Ka Hikitia, and its implications on the daily lives of Māori students in New Zealand’s education system. Extensive information on the secondary school experiences of rangatahi Māori (youth) have been gathered—originally in 2001 and at the end of 2015, through Kia Eke Panuku: Building on Success (Kia Eke Panuku: Building on Success is a secondary school reform initiative that is fully funded by the Ministry of Education, however, this paper represents the view of the authors and is not necessarily the view of the Ministry). Based on the messages from these two points in time, the paper concludes that the promises of Ka Hikitia are yet to be fully realised. If we, as educators, are to leave a legacy of more Māori students fashioning and leading our future, the need for the system to step up still remains.

text: Succeeding as Māori: Māori students’ views on our Stepping Up to the Ka Hikitia Challenge This paper examines the vision and intent of New Zealand’s Māori education policy, Ka Hikitia, and its implications on the daily lives of Māori students in New Zealand’s education system. Extensive information on the secondary school experiences of rangatahi Māori (youth) have been gathered—originally in 2001 and at the end of 2015, through Kia Eke Panuku: Building on Success (Kia Eke Panuku: Building on Success is a secondary school reform initiative that is fully funded by the Ministry of Education, however, this paper represents the view of the authors and is not necessarily the view of the Ministry). Based on the messages from these two points in time, the paper concludes that the promises of Ka Hikitia are yet to be fully realised. If we, as educators, are to leave a legacy of more Māori students fashioning and leading our future, the need for the system to step up still remains.

year: 2017