You might have heard something about Internet Protocol version 4 (IPv4) causing possible connectivity problems in future if web users don’t begin using the newer IPv6. Well, those problems have arrived, with numerous websites including eBay, Amazon, LinkedIn and others hit by outages yesterday. Also affected were major network providers like AT&T, Comcast, Time Warner and Verizon, as well as BT and Virgin in the UK.

At first, several ISPs thought that the outage was due to local flooding, but apparently that’s not the case. Rather, older routers and their inability to cope with the web’s ever-growing routing table is to blame.

The problem is that Border Gateway Protocol (BGP) routers have to store a map of the web that defines which range of IP addresses belongs to which network. But because Ipv4 space is becoming increasingly scarce (due to the millions of new “things” added online each week), ISPs and registrars have been assigning smaller netblocks to their customers, which makes everything more fragmented. Some older routers can only store 512k entries, and the Internet’s routing table has now outgrown this limit.

IPv4 is the most common protocol for routing traffic online, but in recent months concerns have been raised over a phenomenon called “address exhaustion”. The problem is that with the rapid proliferation of the Internet of Things, the number of IP addresses in the world is growing rapidly, and IPv4 simply doesn’t have enough to go round.

For those with older routers who’ve been affected by the problems, Cisco has published guidelines on how to fix the issue. But this is just a fix, the real solution is to update your router. The routing table is only going to get larger over the next few years, until networks finally catch on to IPv6 and rely less on IPv4.

photo credit: nicolasnova via photopin cc