title: Measured impact of crooked traceroute

authors: Luckie, Matthew John

subjects: computer science

abstract: Data collected using traceroute-based algorithms underpins research into the Internet’s router-level topology, though it is possible to infer false links from this data. One source of false inference is the combination of per-flow load-balancing, in which more than one path is active from a given source to destination, and classic traceroute, which varies the UDP destination port number or ICMP checksum of successive probe packets, which can cause per-flow load-balancers to treat successive packets as distinct flows and forward them along different paths. Consequently, successive probe packets can solicit responses from unconnected routers, leading to the inference of false links. This paper examines the inaccuracies induced from such false inferences, both on macroscopic and ISP topology mapping. We collected macroscopic topology data to 365k destinations, with techniques that both do and do not try to capture load balancing phenomena.We then use alias resolution techniques to infer if a measurement artifact of classic traceroute induces a false router-level link. This technique detected that 2.71% and 0.76% of the links in our UDP and ICMP graphs were falsely inferred due to the presence of load-balancing. We conclude that most per-flow load-balancing does not induce false links when macroscopic topology is inferred using classic traceroute. The effect of false links on ISP topology mapping is possibly much worse, because the degrees of a tier-1 ISP’s routers derived from classic traceroute were inflated by a median factor of 2.9 as compared to those inferred with Paris traceroute.

text: Measured impact of crooked traceroute Data collected using traceroute-based algorithms underpins research into the Internet’s router-level topology, though it is possible to infer false links from this data. One source of false inference is the combination of per-flow load-balancing, in which more than one path is active from a given source to destination, and classic traceroute, which varies the UDP destination port number or ICMP checksum of successive probe packets, which can cause per-flow load-balancers to treat successive packets as distinct flows and forward them along different paths. Consequently, successive probe packets can solicit responses from unconnected routers, leading to the inference of false links. This paper examines the inaccuracies induced from such false inferences, both on macroscopic and ISP topology mapping. We collected macroscopic topology data to 365k destinations, with techniques that both do and do not try to capture load balancing phenomena.We then use alias resolution techniques to infer if a measurement artifact of classic traceroute induces a false router-level link. This technique detected that 2.71% and 0.76% of the links in our UDP and ICMP graphs were falsely inferred due to the presence of load-balancing. We conclude that most per-flow load-balancing does not induce false links when macroscopic topology is inferred using classic traceroute. The effect of false links on ISP topology mapping is possibly much worse, because the degrees of a tier-1 ISP’s routers derived from classic traceroute were inflated by a median factor of 2.9 as compared to those inferred with Paris traceroute.

year: 2011-01

title: They're not doing bad for their age: ageing, leisure and active living.

authors: Grant, Bevan C.

subjects: education

abstract: The article focuses on the life of elderly people. The majority of older people are fit and well, live independently and are actively engaged in their community. However, the time has come to view ageing in a more constructive way and in so doing liberate people in their last 10, 20 or 30 years of life from the negative effects of the labels--ageing, aged and old. In addition to personal characteristics, the positive ageing experience is also influenced by the way older people themselves interact with and negotiate the many forces in relationships, stereotypes and prejudices, economic conditions, social and cultural expectations, living arrangements and job opportunities. The evidence suggests that these forces take on greater significance with age because related inequalities experienced in earlier life tend to be accentuated in the later years , particularly for women.

text: They're not doing bad for their age: ageing, leisure and active living. The article focuses on the life of elderly people. The majority of older people are fit and well, live independently and are actively engaged in their community. However, the time has come to view ageing in a more constructive way and in so doing liberate people in their last 10, 20 or 30 years of life from the negative effects of the labels--ageing, aged and old. In addition to personal characteristics, the positive ageing experience is also influenced by the way older people themselves interact with and negotiate the many forces in relationships, stereotypes and prejudices, economic conditions, social and cultural expectations, living arrangements and job opportunities. The evidence suggests that these forces take on greater significance with age because related inequalities experienced in earlier life tend to be accentuated in the later years , particularly for women.

year: 2004

title: What land is included?

authors: Oppatt, Neil

abstract: Neil has served the Rotorua District as both a Rotorua District Councillor for 15 years and now 9 years as a BOP Regional Councillor. Throughout this time Neil has been actively involved in the cleanup of Rotorua's lakes. He is presently a BOPRC appointee on the Rotorua Te Arawa Lakes Strategy Group and was an RDC appointee on its predecessor.
He has held positions as Chairman of RDC’s Finance Committee, BOPRC’s Operations and Regulations Committee and the Special Projects Committee set up to address Rotorua lake issues. Neil chaired the Lake Okareka Action Plan Committee and was a BOPRC appointee on the Lake Tarawera Action Plan Committee. Presently he is the BOPRC appointee on the Rotorua catchment Stakeholders Advisory Group.

text: What land is included? Neil has served the Rotorua District as both a Rotorua District Councillor for 15 years and now 9 years as a BOP Regional Councillor. Throughout this time Neil has been actively involved in the cleanup of Rotorua's lakes. He is presently a BOPRC appointee on the Rotorua Te Arawa Lakes Strategy Group and was an RDC appointee on its predecessor.
He has held positions as Chairman of RDC’s Finance Committee, BOPRC’s Operations and Regulations Committee and the Special Projects Committee set up to address Rotorua lake issues. Neil chaired the Lake Okareka Action Plan Committee and was a BOPRC appointee on the Lake Tarawera Action Plan Committee. Presently he is the BOPRC appointee on the Rotorua catchment Stakeholders Advisory Group.

year: 2013