Isolated Internet Outages Caused By BGP Spike

28 Aug 2014 • anandtech.com

Two days later, and there is a pretty clear understanding of what happened. Older Cisco core internet routers with a default configuration only allowed for a maximum 512k routes for their Border Gateway Protocol (BGP) tables. With the internet always growing, the number of routes surpassed that number briefly on Tuesday, which caused many core routers to be unable to route traffic.

BGP is not something that is discussed very much, due to the average person never needing to worry about it, but it is one of the most used and most important protocols on the internet. The worst part of the outage was that it was known well in advance that this would be an issue, yet it still happened.

Why?

Although you could be quick to jump and blame Verizon for the outage, it has to be noted that Cisco issued a warning to customers explaining that the memory which is allocated for the BGP table would be very close to being full, and gave specific instructions on how to correct it. This warning came several months ago. Unfortunately not all customers of Cisco heeded or received the warning, which caused the brief spike to cripple parts of the internet.

Sounds like those Cisco memos should really be mandatory reading.