512K Day was a Lucky Day
Many of us have driven a car past fuel stations while the fuel gauge points to empty, hoping to make it to our destination or favorite station. If you make it, you feel lucky. If you stall on the side of the road, you can only question what you were thinking. Those must have been the feelings that many IT administrators had on Tuesday, August 12th.
In May, Cisco published a notice regarding the prospect of reaching the 512k route mark for Internet routing tables. 512k is the maximum or default routing table size in many, generally older, routers and switches. Once the number of Internet routes exceeded 512k, equipment issues or missed routes would occur. As it turned out, the day that the number of routes exceeded 512k was August 12th, dubbed, "512k Day."
Fortunately, 512k Day issues were fairly isolated and limited in impact. It was a lucky day. While there were warnings like that from Cisco, they were not widespread and some went unheeded. SevOne co-founder and CTO, Vess Bakalov, put it this way as reported on ARS Technica:
The issue appears to have surprised many network engineers. Network-hardware vendors did not give much warning as to the dangers of the default configuration of older routers, and corporate executives likely put off resolving the issue.
The 512k issue is now being resolved, but is likely to appear sporadically for a while as routing tables continue to grow. Resolution comes from reallocation of available routing table memory space in older routers and servers from IPv6 use to IPv4. This reallocation, unfortunately, adversely affects the long-term resolution to "512k" which is to transition to IPv6 equipment and networks.
Vess Bakalov didn't mention it in his quote, but he has been preparing for the advent of all-IPv6 for some time. SevOne architected its performance monitoring platform to operate with and report on native IPv6, IPv4, and dual stack environments.
512k Day was a Lucky Day. But, paraphrasing Earnest Hemingway, it's better to make your own luck.