Perhaps information regarding gmond on networks set up through cisco catalyst switches should be mentioned in the ganglia documentation. I think by default multicast traffic on the catalyst will flood all devices unless configured properly. Here is a relavent snipet from a message forum, with a link to cisco document.
-- If what you are trying to do, is minimizing the impact on your network due to a multicast application, this link may describe what you want to do: http://www.cisco.com/warp/public/473/38.html We set up our switches according to this after a consultant came in and installed an application multicasting several hundred packets per second. This made the network functional again. -- Lester
