Publications 

As I write this, on the 23rd June 2009, I’ve been reminded that some 20 years ago, on the night of the 23rd June 1989, Robert Elz of the University of Melbourne and Torben Neilsen of the University of Hawaii completed the connection work that brought the Internet to Australia with a permanent connection via a 56kbps satellite circuit.

Since that day we’ve evidently connected some 56.8% of the local population, or 12,073,852 Australians, to the Internet (according to recent Internet user statistics published by the ITU-T). While that’s an impressive outcome, I suppose I should say at the outset that when we started down this path in Australia some twenty years ago we had no intention of achieving this scale of outcome. Indeed we never thought that this type of data networking would ever cross the boundary from an esoteric tool to assist a select group of computer literate researchers and academics into the mainstream of society, and current concepts like twitter and social networking were completely foreign to us. In truth all we were trying to do was to save a bit of money for the universities and have some fun experimenting with some pretty novel technology on the way. (more…)

For some years now I’ve been running a set of scripts that attempt to model the consumption of IPv4 addresses and then use this model to look forward in time and predict the date at which the pool of unallocated IPv4 addresses will be exhausted. The results of this model, together with a description of the process used in the model can be found at http://ipv4.potaroo.net. As the predicted date of exhaustion is getting to be a “right here and right now problem” rather than a “comfortably in the vague future, so its really someone else’s problem” its probably worth revisiting the model and the assumptions it makes so that you can choose for yourself whether to believe its predictions - or continue to press on with IPv4 and blithely ignore the entire problem for yet another day. (more…)

In this article I’d like to look at the topic that was presented at a session at the 74th meeting of the IETF in March 2009, on Address sharing (the SHARA BOF), and look at the evolution of NAT architectures in the face of the forthcoming depletion of the unallocated IPv4 address pool. (more…)

Here in my part of the world the season has well and truly turned from summer to autumn, which means that another year has come and gone. I thought that it might be time to give MTU examination a rest for a month or more and instead review the last 12 months in BGP-land and see what’s been happening there. (more…)

In the previous column I explored an error I had encountered where an IPv4-only web browser on my dual stack system could connect to a web server and retrieve the web pages, while a dual stack configured browser managed to get itself stuck displaying a white page. The Problem was a Path MTU “blackhole” and one possible method to avoid this is to reduce the local MTU size. But does a smaller packet size mean slower performance? (more…)

I have seen a number of commentaries and presentations in recent times that claim that IPv6 is identical to IPv4 in every respect except one: namely more addresses. Of course that’s not just “more” addresses in the sense that 128 addresses are “more” than 32 addresses, but that’s 2 to the power 96 times “more” addresses. Here we’re talking massively, unimaginably massively, “more” addresses in IPv6! I must admit to some sympathy for such a claim given that I find the assertions that IPv6 provides superior QoS capability, better, security, improved mobility support or better anything else, as compared to IPv4, to be an expression of largely wishful thinking. There have been some minor tweaks in IPv6 in this respect, but nothing very major.

But there is one rather critical difference, and that is the deliberate change in the IPv6 with respect to MTU handling and packet fragmentation, and this relatively minor change in IPv6 has some really quite critical implications. In this article I’d like to illustrate some of the implications of this change with respect to the IPv6 treatment of packet fragmentation by taking an in-depth look at the IPv6 packet flows and why and how this change to packet fragmentation management can cause service-level disruption. (more…)

In November 2008 APNIC publically released its resource certification toolkit. This system allows a holder of APNIC-allocated IP number resources (IP addresses and AS numbers) to have these resources certified by APNIC as being currently held by the entity through the issuance and publication of a digital resource certificate. The system also allows every such resource holder to generate signed attestations and digital authorities relating to the use of their allocated address space in a routing context, or within other administrative or technically focussed processes that can make use of verifiable attestations relating to a holder’s current “right-of-use” over such IP number resources. In this article I will look at resource certificates in some detail, looking at the technology that underpins certification structures, and the potential use of these instruments in securing inter-domain routing and potentially in the area of the emerging need to support address transfers in IPv4.
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All this talk of address exhaustion in IPv4 has prompted some reaction from the address communities in terms of the consideration of various forms of a “transfer policy for IPv4″ in the APNIC, ARIN and RIPE regions. I’d like to look at these transfer policies in a little more detail and take the opportunity to share some of my thoughts about the situation. (more…)

Throughout its relatively brief history the Internet has continually challenged our preconceptions about networking and communications architectures. For example, the concept that the network itself has no role in management of the network’s own resources, and that resource allocation is the result of interaction between competing end-to-end data flows was certainly a novel innovation, and for many it has been a very confronting concept. (more…)

The IETF’s developmental work on IPv6 has included the study of the particular issues associated with transition to IPv6 from the outset. The first initial effort in the transition space, at IETF29 in March 1994, was termed “TACIT”, an acronym of Transition and Coexistence including Testing. While this was admittedly a forced acronym, (more…)

If you have enabled IPv6 on your computer, and in an idle moment you’ve browsed through the interface configuration information for IPv6 addresses you may have been a little surprised by the fact that there’s not just one IPv6 address that’s been loaded, but many. With IPv4 there was a single address that was bound to each interface, but when using IPv6 its not so clear, and an interface can have a number of IPv6 addresses simultaneously. (more…)

On June 17th and 18th the Organization for Economic Co-operation and Development (OECD) hosted a Ministerial Meeting on the Future of the Internet Economy, attended by Ministers for communications from the 30 OECD member nations and some 15 other nations, all to talk about the future of the Internet Economy. (more…)