UW network handles inauguration traffic (updated)
Wednesday, January 21, 2009
Traffic on the UW-Madison campus network roughly doubled during the presidential inauguration today. The new 21st Century Network easily handled over 1000 simultaneous on-campus viewers of the inauguration between all the DATN (Digital Academic Television Network) news channels.
Traffic peaked from roughly 30 minutes before the ceremony until several minutes after the acceptance speech. Some of these views were in classrooms and lecture halls with multiple people. Network traffic from Chicago peaked at 20% of capacity during this time. Internet2's commercial peering connections reached capacity during the same time. There was no impact to Internet2's research and education network.
Details
The Presidential Inauguration was made available on computers on the UW-Madison campus on DATN. Channels such as C-SPAN, CNN, Fox and MSNBC can be viewed via DATN on computers in classrooms, lecture halls, computer labs, libraries, guest rooms, and UW Housing rooms.
There are two ways to watch such network streams: Multicast (where many are able to watch one stream simultaneously, and Unicast (where each stream is carried separately). If 1000 users view the same unicast video stream, 1000 copies need to be carried across the network. With multicast, only a single copy of the stream is carried across the network and is replicated by the network out each user's network port.
The campus uses WiscNet, Wisconsin's research and education network, for its commercial Internet access. Inbound traffic peaked on WiscNet at 6.6 Gigabits/sec at about 11:00 am, approximately double the traffic expected on the first day of the semester if there was no presidential inauguration. WiscNet's external connections weathered the traffic well, except for peering with one popular video hosting network. WiscNet network engineering was able to quickly shift traffic before the inauguration so users experienced no problems.