Hi Freek/All; As promised here is the running instance of the Internet2 Topology Service, currently used for ION network: http://dcn-ts.internet2.edu:8012/perfSONAR_PS/services/topology Example messages are here: http://anonsvn.internet2.edu/svn/perfSONAR-PS/trunk/perfSONAR_PS-TopologySer... And if you need a quick and dirty client, that is available here: http://anonsvn.internet2.edu/svn/perfSONAR-PS/trunk/Shared/client/client.pl Thanks; -jason