An Opinion in Defence of NATs

Network Address Translation has often been described as an unfortunate aberration in the evolution of the Internet, and one that will be expunged with the completion of the transition of IPv6. I think that this view, which appears to form part of today’s conventional wisdom about the Internet unnecessarily vilifies…


IPv6 Fragmentation Extension Headers, Part 2

The first part of this article looked at what happens when an authoritative DNS server delivers fragmented UDP responses to DNS resolvers using IPv6. The result from this experiment was that: Some 37% of endpoints used IPv6-capable DNS resolvers that were incapable of receiving a fragmented IPv6 response over UDP.…


IPv6, Large UDP Packets and the DNS

The IPv6 protocol introduced very few changes to its IPv4 predecessor. The major change was of course the expansion of the size of the IP source and destination address fields in the packet header from 32-bits to 128-bits. There were, however, some other changes that apparently were intended to subtly…


Notes from IETF 99 – The Other Bits

After pulling out the notes from the IEPG meeting and aspects of the DNS, here are the rest of the items that I personally found to be of interest at IETF 99 last week. IPv6 Operations – Apple’s Happier Eyeballs? The way in which browsers leverage the potential opportunities offered…


Notes from IETF99 – DNS Activity

Interest in the DNS appears to come in waves. It’s quiet for a few years, then there is a furious burst of activity. We appear to be in the middle of a burst of activity, and there is probably enough material presented at the recent IETF meeting to cover the…


Notes from IETF 99 – The IEPG Meeting

It’s hard to classify the IEPG meetings that occur at the start of the IETF week. Many years ago they had a role in allowing network operators to talk to other operators about what they were seeing and what they were thinking about. Those days are long since over, and…


BGP More Specifics

The Border Gateway Protocol (BGP) is the routing protocol that literally keeps the Internet glued together. The public Internet is composed of some 58,000 component networks (BGP calls them “Autonomous Systems” (AS’s)), many of which are very small, while some are very large both in terms of geographical coverage and…


DNS OARC 26

OARC 26 was held in May in Madrid. Here are my impressions of the meeting, drawn from some presentations that I found to be of personal interest. All the presentations can be found at OARC’s web site.


RIPE 74

RIPE 74 was held in May in Budapest, and as usual it was a meeting that mixed a diverse set of conversations and topics into a very busy week. Here are my impressions of the meeting drawn from a number of presentations that I found to be of personal interest.…


BBR TCP

The Internet was built using an architectural principle of a simple network and agile edges. The basic approach was to assume that the network is a simple collection of buffered switches and circuits. As packets traverse the network they are effectively passed from switch to switch. The switch selects the…