Yesterday, at around 11:50am, we had some reports of unusual activity on our ring network.
We traced this down to elevated levels of CPU usage on our switches. Further investigation pointed to a high level of IGMP traffic being received.
We further traced this to our LINX Extreme peering port in London and shut the port down. This resolved the issue instantly.
We contacted our Connexions provider, who provide our LINX ports. They did investigation to ensure the traffic was not originating internally and then passed the query onto LINX.
LINX confirmed this morning that they had a member port injecting IGMP traffic to the peering LAN yesterday and that this has now been resolved.
We have re-enabled our LINX Extreme port and confirmed the issue no longer exists.
We will re-enable our peering connections via this LAN shortly.