On August 12th, Internet outages occurred as a result of a burst of temporary growth in the IPv4 routing table. This resulted in some routers crossing the important 512K mark, as many older routers are limited to routing tables smaller than this, and fail when the table grows too large. The addition of about 15,000 new IPv4 routes by Verizon to the roughly 500,000 current entries had the effect of clearly demonstrating the 512K effect. Those routes were later removed, but IPv4 routing table growth is inexorable, and will permanently reach 512K shortly. This table growth is further evidence of the continued value of the IPv4 Internet. In fact, last week more IPv4 prefixes were added to the table than IPv6 prefixes, meaning that IPv6, although trying to overtake IPv4, faces a Sisyphean task of catching something that is accelerating away. For example, last week IPv6 added about 72 prefixes to the routing table, and IPv4 added 1418. One author notes the absence of IPv6 NAT, and the requirements that multi-homed businesses begin running BGP themselves if they convert to IPv6. What will be the effect on the routing table then? It’s worth perusing the comments section for the above article for some lively and informed debate.