Have you experienced random issues on the Internet in the last 24 hours or so? If so you are not alone…
It has been well publicised that the world is running out of IP addresses – the unique addresses used to identify devices connected to the Internet. The IPv4 addressing scheme was designed as far back as the early 1980’s, which is an age in computing terms. Its successor, IPv6 has been around for many years but is not (yet) widely used. To give a little more breathing room IANA, the authority responsible for IPv4 address allocation, regularly make more classes of IPv4 addresses available for use, and as a result the Global Routing Table that all ISP’s use in their datacentres to route traffic around the Internet has grown to over 500,000 routes.
So what’s the issue?
Well, some older networking kit used by ISP’s only has a limited amount of memory available to hold the Global Routing Table and associated data, and that means a limit of approximately 500,000 routes (for the techies out there you can do the maths – start with the size of the memory allocated which is 219). The effect of this is that some routes have to get dropped, but there is no consistency between the different routers as to which routes get dropped, and this is why the problems appear to be sporadic and random in nature. Note this issue only affects ISP equipment, not your average home user router.
The fix is fairly straightforward for the ISP’s; they just need to change some settings and possibly reboot a few pieces of equipment, but getting round to it may take some time, and while the work is in progress we can all expect some random disruption to Internet traffic. The big question is didn’t anyone know this was going to happen? And the answer is yes, they did, but very few ISP’s adequately prepared for it. The event is unofficially known as 512k day (did you do the maths?), and was widely predicted (within technical networking circles) to hit on August 12th 2014. The similarity with Y2K bug is striking but unlike the preparation for Y2K, the response from the large ISP’s over 512K day has been found wanting, and as a result the effect has been more widely felt by the users of the Internet.
Canadian ISP Shaw stumbles around internet with mystery ‘routing’ sickness – The Register
Happy 512k day! This is why the Internet is broken. – Reddit
Internet hiccups today? You’re not alone. Here’s why – ZDnet
512KDay: Why the internet is BROKEN – The Register
Follow the story unfolding on Twitter – #512k