I was reading my mails today and I bumped into some problems that Internet2 routers faced a couple of days ago with some multicast traffic sent from a host in France. Apparently the host was sending 44Mbit of traffic to a multicast group and that was more than enough to raise a very high load on some routers and cause problems to some firewalls too. Their solution was to either blacklist the host or to disable SAP listen on their routers.
To read more you can check the thread “Another SAP Storm?” from wg-multicast@internet2.edu All things related to multicast .
The same problem appeared on GrNET routers too, but unfortunately they don’t have any public archives of their exchanged mails on the problem. The only way to take a look at this problem from the GrNET point of view is to check on the GrNET router status page, click on the load of some routers and check the spike that appears on Wednesday night in the weekly graph.
Quite interesting…