Recent Articles
Stateless and DNSperate!
November 2009
I've often heard it said that the world is full of bad ideas. But no matter how many bad ideas there may be, the good news is that there is always room for one more! So in the spirit of "more is better" I'd like to offer the following as yet another Bad Idea (http://bert.secret-wg.org/BIF/index.html). There is also the intriguing possibility that this flawed concept could be made to work, making this a thoroughly Useless Tool (http://bert.secret-wg.org/Tools/index.html) at the same time! more...
RIPE at 59!
October 2009
RIPE, or Réseaux IP Européens, is a collaborative forum open to all parties interested in wide area IP networks in Europe and beyond. The objective of RIPE is to ensure the administrative and technical coordination necessary to enable the operation of a pan-European IP network. RIPE has been a feature of the European Internet landscape for some twenty years now, and it continues to be a progressive and engaged forum. These days RIPE meets twice a year, and the most recent meeting was held at Lisbon, Portugal, from the 5th to the 9th of October 2009. In this column I'd like to share some of my impressions of this meeting. more...
Is the Transition to IPv6 a "Market Failure?"
September 2009
Many views of the transition to IPv6 assume that the combination of the factors of the imminent exhaustion of the unallocated pool of IPv4 addresses and the conventional dynamics of an open competitive marketplace in the ISP sector will be sufficient to propel the transition to IPv6. The question I would like to pose here is: Is this an appropriate view of the transition to IPv6? An alternative view is that this transition to IPv6 has already stalled over the past decade, and we should be prepared to view the current situation as an instance of a "market failure" in economic terms, where the transition will require the impetus of some form of response associated with the distribution of a "public good", and that conventional market dynamics are in and of themselves incapable of sustaining such a transition. more...
AS Numbers - Again
August 2009
IPv6 is not the only number resource that is running out in the coming couple of years. The same fate awaits the pool of Autonomous System numbers, used to support the inter-domain routing protocol, BGP. In the original design of BGP. In this article I'd like to update the situation that was originally reported here some fours years ago, and look at we are doing about AS Number exhaustion. more...
The State of SIDR
July 2009
In the last week of July the IETF held its 75th meeting in Stockholm. Most of the active working groups hold meetings in the week to review progress, debate current issues in their work and possibly consider the next steps to take in meeting their objectives. The work has been underway for some years now, and in this column I'd like to take a look at where the SIDR work has got to and where it is heading. more...
Twenty Years Later
June 2009
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 bought 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. At best this was all just an experiment and if there was ever going to be some mainstream commercial outcome, then that was the for the telephone companies to work on, and was certainly none of our business. So how and why did all this get started? more...
Predicting the End of the World
May 2009
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...
NAT++: Address Sharing in IPv4
April 2009
It looks like we will need to operate a dual stack Internet for many years yet, and the associated implication is that that we are going to have to make the existing IPv4 Internet span a billion or more new deployed services, and do so without any additional address space. So how are we going to make the IPv4 address pool stretch across an ever-larger Internet? Given that the tool chest we have today is the only one available, then it looks like there is only one answer to this question: Network Address Translation, or NATs. more...
BGP in 2008
March 2009
BGP has been toiling away, literally holding the Internet together, for close to two decades now, and nothing seems to be falling off the edge of the Internet. In October 2006 a workshop convened by the Internet Architecture Board can to the conclusion that: "routing scalability is the most important problem facing the Internet today and must be solved [...] The routing scalability problem includes the size of the DFZ RIB and FIB [and] the implications of the growth of the RIB and FIB on routing convergence times." The question I'd like to ask here is whether anything has changed in this perspective on BGP since late 2006? Are the prospects of the medium term collapse of BGP through scaling overload still a realistic option for the routing environment? Should we still be concerned about routing scaling? Is the BGP sky about to fall on our heads? Lets look at BGP across 2008 to see if any answers to these questions are lurking in the data. more...
Mutterings on MTUs
February 2009
When looking at network performance the conventional belief is that larger parkets are far better than smaller packets. So whenever and however possible you should raise your packet size, or MTU, as larger as possible. "Conventional beliefs" always intrigue me, in that while sometimes these beliefs express basic constraints and truths, at other times they are misleading and just plain wrong. So the question I'd like to look at in this article is: Just how bad is a smaller MTU setting? more ...
A Tale of Two Protocols: IPv4, IPv6, MTUs and Fragmentation
January 2009
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. But there is one more 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 ...
