title: Light, camera, actions: characterizing the usage of IXPs' action BGP communities

authors: Mazzola, Fabricio

subjects: computer science

abstract: Border Gateway Protocol (BGP) communities, an optional message attribute, allow network operators to tag BGP announcements and act on routing decisions. Although widely used, it is so far unclear how prevalent the different types of communities are and the degree to which the different traffic engineering actions have been used. There are two major reasons for this gap: few community values have been standardised and the limited visibility at route collectors. In this paper, leveraging the fact that Internet eXchange Points (IXPs) have sets of well-documented BGP communities, we use their BGP Looking Glasses (LGs) to inspect their route servers and shed light on how IXP members are using action BGP communities. During twelve weeks, we collected and analysed routing data from eight IXPs worldwide, focusing the analysis on the four largest IXPs. We observe that i) over one-third of IXP members (>35.7%) use action communities in at least one route; ii) two-thirds (66.6%) of them are intended to avoid propagating routes, mostly to content providers (CPs); iii) nearly one-third (31.8%) are targeting Autonomous Systems (ASes) that are not present at the IXPs' route servers, resulting in no practical routing effect and only increasing processing and memory storage overheads.

text: Light, camera, actions: characterizing the usage of IXPs' action BGP communities Border Gateway Protocol (BGP) communities, an optional message attribute, allow network operators to tag BGP announcements and act on routing decisions. Although widely used, it is so far unclear how prevalent the different types of communities are and the degree to which the different traffic engineering actions have been used. There are two major reasons for this gap: few community values have been standardised and the limited visibility at route collectors. In this paper, leveraging the fact that Internet eXchange Points (IXPs) have sets of well-documented BGP communities, we use their BGP Looking Glasses (LGs) to inspect their route servers and shed light on how IXP members are using action BGP communities. During twelve weeks, we collected and analysed routing data from eight IXPs worldwide, focusing the analysis on the four largest IXPs. We observe that i) over one-third of IXP members (>35.7%) use action communities in at least one route; ii) two-thirds (66.6%) of them are intended to avoid propagating routes, mostly to content providers (CPs); iii) nearly one-third (31.8%) are targeting Autonomous Systems (ASes) that are not present at the IXPs' route servers, resulting in no practical routing effect and only increasing processing and memory storage overheads.

year: 2022-12-06

title: Using collaborative CoRe design in chemistry education to promote effective partnerships between associate and student teachers

authors: Hume, Anne Christine

abstract: This article is a follow-up to my paper published in 2010 (Hume, 2010). In that paper I reported on the use of Content Representations (CoRes) in a chemistry education course to give student teachers insights into the professional knowledge of experienced practitioners: notably their pedagogical content knowledge (PCK), which is “… [the] understanding of how particular topics, problems, or issues are organised, represented, and adapted to the diverse interests and abilities of learning, and presented for instruction” (Shulman, 1987, p. 8). introduced by Shulman (1987) as an academic construct to describe a tacit category of teachers’ professional knowledge base, the exact nature of PCK has been extensively explored and debated. From this debate some agreement has emerged about the components that comprise a teacher’s PCK. This has been identified by Magnusson et al. (1999) as a teacher’s:
• orientations towards science teaching (since teachers’ knowledge and beliefs related to their teaching goals and approaches will influence their classroom practice);
• knowledge of curriculum;
• knowledge of assessment (since what is to be assessed, how and why also influences a teacher’s practice);
• knowledge of students’ understanding of science;
• knowledge of instructional strategies.

text: Using collaborative CoRe design in chemistry education to promote effective partnerships between associate and student teachers This article is a follow-up to my paper published in 2010 (Hume, 2010). In that paper I reported on the use of Content Representations (CoRes) in a chemistry education course to give student teachers insights into the professional knowledge of experienced practitioners: notably their pedagogical content knowledge (PCK), which is “… [the] understanding of how particular topics, problems, or issues are organised, represented, and adapted to the diverse interests and abilities of learning, and presented for instruction” (Shulman, 1987, p. 8). introduced by Shulman (1987) as an academic construct to describe a tacit category of teachers’ professional knowledge base, the exact nature of PCK has been extensively explored and debated. From this debate some agreement has emerged about the components that comprise a teacher’s PCK. This has been identified by Magnusson et al. (1999) as a teacher’s:
• orientations towards science teaching (since teachers’ knowledge and beliefs related to their teaching goals and approaches will influence their classroom practice);
• knowledge of curriculum;
• knowledge of assessment (since what is to be assessed, how and why also influences a teacher’s practice);
• knowledge of students’ understanding of science;
• knowledge of instructional strategies.

year: 2011

title: Mentoring and teaching in academic settings:  Professional and cultural identities from one Pākehā’s perspective

authors: Middleton, Sue

subjects: biculturalism

abstract: When invited to respond to the paper on “Mentoring Māori in a Pākehā framework” by Hook, Waaka and Raumati (2007), I hesitated. Mentoring was not a term I had previously used in my professional thinking or academic writing: unlike Barbara Grant (Ratima & Grant, 2007), I had not been involved in formal mentoring programmes or immersed myself in the mentoring literature. As a Pākehā, I was not qualified to evaluate the authors’ definition of a Māori framework. At first glance, the target paper’s focus seemed to be on mentoring in commercial, rather than academic workplaces. My experience had been as a teacher, the last 30 years having been in a university School of Education. I was persuaded to undertake this commentary on the grounds that academic work involves nurturing, advising and supporting younger or less experienced colleagues, as well as students – tasks identified as mentoring in the Hook et al. paper. The following comments are informed by my everyday practices as teacher, thesis supervisor and researcher, and by my former management roles as an assistant dean of graduate studies and head of department. My angle of vision and conceptual resources are those of a (Pākehā and feminist) sociologist of education.

text: Mentoring and teaching in academic settings:  Professional and cultural identities from one Pākehā’s perspective When invited to respond to the paper on “Mentoring Māori in a Pākehā framework” by Hook, Waaka and Raumati (2007), I hesitated. Mentoring was not a term I had previously used in my professional thinking or academic writing: unlike Barbara Grant (Ratima & Grant, 2007), I had not been involved in formal mentoring programmes or immersed myself in the mentoring literature. As a Pākehā, I was not qualified to evaluate the authors’ definition of a Māori framework. At first glance, the target paper’s focus seemed to be on mentoring in commercial, rather than academic workplaces. My experience had been as a teacher, the last 30 years having been in a university School of Education. I was persuaded to undertake this commentary on the grounds that academic work involves nurturing, advising and supporting younger or less experienced colleagues, as well as students – tasks identified as mentoring in the Hook et al. paper. The following comments are informed by my everyday practices as teacher, thesis supervisor and researcher, and by my former management roles as an assistant dean of graduate studies and head of department. My angle of vision and conceptual resources are those of a (Pākehā and feminist) sociologist of education.

year: 2007-12