We recently encountered a problem after upgrading to Catalyst 3750X switches in several of our buildings. The complaints came from the desktop support groups that were attempting to re-image workstations using Symantic ghost imgaging using multicast. The semester before, with Catalyst 2950 (layer 2) switches in the closets the re-imaging worked very well. Since then the buildings we upgraded to the Catalyst 3750X (still running at layer 2) switches, the performance of re-imaging has dropped to near use-less. They report if they simultaneously do only 6 workstations at a time it works ok, but if they try to do more than 6 the performance drops significantly to the point where things start timing out. The layer 3 device is an upstream Catalyst 6500 where the Vlan is created and PIM is configured. The layer 3 configuration has not changed prior to the switch replacements, all we did was replace the 2950's with 3750X's and the multicast performance changed for the worse. It doesn't appear to have any unicast problems.
Any information or if anyone has encountered this kind of problem, feedback would be greatly appreciated.
Thanks!
