Microsoft patch Tuesday impact on university network edge links

The second Tuesday of every month Microsoft releases patch bundles for its software product line. Depending on the size of the organization, this may have significant impact on the Internet and networking infrastructure.

Washington University in St. Louis has 3 x 10G and 1 x 20G links to the commodity and research Internet through Cogent, Lumen, Spectrum, and Internet2. In November of 2020, the patch cycle hit the Internet links pretty hard.

WashU is normally a moderate sized campus. Due to COVID-19, the number of active devices is down by 25% - 50% due to remote classes and work. To put this into perspective, there were approximately 45K devices online during the patch Tuesday event:

washu clients

Looking at the edge links between 1 - 3AM all four of the Internet links started to reach their maximum capacities:

microsoft patch tuesday impact on network edge links

It is not often network engineers pull the covers back and show off internal network utilization statistics. The nice thing about working for a university, transparency is encouraged.