PING

In his regular monthly spot on PING, APNIC’s Chief Scientist Geoff Huston discusses the question of subnet structure, looking into the APNIC Labs measurement data which collects around 8 million discrete IPv6 addresses per day, worldwide. Subnets are a concept which "came along for the ride" in the birth of Internet Protocol, and were baked into the address distribution model as the class-A, class-B and class-C subnet models (there are also class-D and class-E addresses we don't talk about much). The idea of a sub-net is distinct from a routing network, many pre-Internet models of networking had some kind of public-local split, but the idea of more than one level of structure in what is "local" had to emerge when more complex network designs and protocols came into being. Subnets are the idea of structure inside the addressing plan, and imply logical and often physical separation of hosts, and structural dependency on routing. There can be subnets inside subnets, its "turtles all the way down" in networks. IP had an ability out-of-the-box to permit subnets to be defined, and when we moved beyond the classful model into classless inter-domain routing or CIDR, the idea of prefix/length models of networks came to life. But IPv6 is different, and the assumption we are heading to a net-subnet-host model of networks may not be applicable in IPv6, or in the modern world of high speed complex silicon for routing and switching. Geoff discusses an approach to modelling how network assignments are being used in deployment, which was raised by Nathan Ward in a recent NZNOG meeting. Geoff has been able to look into his huge collection of IPv6 addresses and see what's really going on.

This time on PING Doug Madory from Kentik discusses his recent measurements of the RPKI system worldwide, and it's visible impact on the stability and security of BGP. Doug makes significant use of the Oregon RouteViews repository of BGP data, a collection maintained continuously at the University of Oregon for decades. It includes data from back to 1997, originally collected by the NLANR/MOAT project and has archives of BGP Routing Information Base (RIB) dumps taken every two hours from a variety of sources, and made available in both human-readable and machine readable binary formats. This collection has become the de-facto standard for publicly available BGP state worldwide, along with the RIPE RIS collection. As Doug discusses, research papers which cite Oregon RouteViews data (over 1,000 are known of, but many more exist which have not registered their use of the data) invite serious appraisal because of the reproducibility of the research, and thus the testability of the conclusions drawn. It is a vehicle for higher quality science about the nature of the Internet through BGP. Doug presented on RPKI and BGP, at the APOPS session held in February at APRICOT/APNIC57 Bangkok, Thailand

In this episode of PING, APNIC’s Chief Scientist Geoff Huston discusses Starlink again, and the ability of modern TCP flow control algorithms to cope with the highly variant loss and delay seen over this satellite network. Geoff has been doing more measurements using starlink terminals in Australia and the USA, at different times of day exploring the system behaviour. Starlink has broken new ground in Low Earth Orbit internet services. Unlike Geosynchronous satellite services which have a long delay but constant visibility of the satellite in stationary orbit above, Starlink requires the consumer to continuously re-select a new satellite as they move overhead in orbit. In fact, a new satellite has to be picked every 15 seconds. This means there's a high degree of variability in the behaviour of the link, both between signal quality to each satellite, and in the brief interval of loss ocurring at each satellite re-selection window. Its a miracle TCP can survive, and in fact in the case of the newer BBR protocol thrive, and achieve remarkably high throughput, if the circumstances permit. This is because of the change from a slow start, fast backoff model used in Cubic and Reno to a much more aggressive link bandwidth estimation model, which continuously probes to see if there is more room to play in.

This time on PING, Dr Mona Jaber from Queen Mary University of London (QMUL), discusses her work exploring IoT, Digital Twins and Social Science led research in the field of networking and telecommunications. Dr Jaber is a senior lecturer in QMUL and is the founder and director of the Digital Twins for Sustainable Development Goals (DT4SDG) at QMUL. She was one of the invited Keynote speakers at the recent APRICOT/APNIC57 meeting held in Bangkok, and the podcast explores the three major themes explored in her keynote presentation. The role of deployed fibre optic communication systems in measurement for sustainable green goals Digital Twin Simulation platforms for exploring the problem space Social Sciences led research, an inter-disciplinary approach to formulating and exploring problems which has been applied to Sustainable Development-related research through technical innovation in IoT, AI, and Digital Twins. The Fibre Optic measurement method is Distributed Acoustic Sensor or DAS: "DAS reuses underground fibre optic cables as distributed strain sensing where the strain is caused by moving objects above ground. DAS is not affected by weather or light and the fibre optic cables are often readily available, offering a continuous source for sensing along the length of the cable. Unlike video cameras, DAS systems also offer a GDPR-compliant source of data." The DASMATE Project at theengineer.co.uk This Episode of PING was recorded live in the venue and is a bit noisy compared to the usual recordings, but it's well worth putting up with the background chatter!

In this episode of PING, APNIC’s Chief Scientist Geoff Huston discusses the European Union's consideration of taking a role in the IETF, as itself. Network engineers, policy makers and scientists from all around the world have participated in IETF but this is the first time an entity like the EU has considered participation as itself in the process of standards development. What's lead to this outcome? What is driving the concern that the EU as a law setting and treaty body, an inter-governmental trade bloc needs to participate in the IETF process? Is this a mis-understanding of the nature of Internet Standards development or does it reflect a concern that standards are diverging from society's needs? Geoff wrote this up in a recent opinion piece on the APNIC Blog and the podcast is a conversation around the topic.

This time on PING we have Phil Regnauld from DNS Operations Analysis & Resource Center (DNS-OARC) talking about the three distinct faces OARC presents to the community. Phil came to the OARC presidents role, replacing Keith Mitchell who was the founding president since 2008 through to this year. Phil previously has worked with the Network Startup Resource Centre (NSRC) and with AFNOG, and the Francophone Internet community at large. DNS OARC has at least 3 distinct faces. It is a community of DNS operators and researchers, who maintain an active ongoing dialogue face to face in workshops and online in the OARC Mattermost community hub. Secondly it is a home, repository and ongoing development environment for DNS related tools such as DNSVIZ (written by Casey Deccio) hosting the AS112 project, and development of the DSC systems amongst many other tools. Thirdly it is the organiser and host of the Day In The Life or DITL activity, the periodic collection of 48-72 hours of DNS traffic from the DNS root operators, and other significant sources of DNS traffic. Stretching back over 10 years DITL is a huge resource for DNS research, providing insights in the use of DNS and its behaviour on-the-wire.