I have a strange problem and I don't know if it is specific to the Windows Vista operating system or my network configuration. Here is my scenario, I have 2 Windows Vista Ultimate clients that causes all other users on the network to not be able to connect to the internet when either of the Windows Vista clients are downloading files from the internet. During my testing I would open a command prompt from one of the clients and perform a transient ping to the inside interface of the 2651XM router that is used to terminate a DSL connection to the internet. During the download process the ping packets begin to become increasingly worse with response times until the Windows Vista client reaches over 500KB/s and then the router becomes completely unresponsive or I begin to see severe packet loss.
I have all clients connecting to a 3560G switch and their gateways are set for a PIX515E that has its E1 interface configured on a vlan'd interface (VLAN200) on the 3560G and its E0 configured on another switchport but configured for a different vlan (VLAN300). The PIX515E is configured to use the 2651XM router as its gateway to the internet and the 2651XM's Fa0/0 is configured on the same vlan as the PIX515E's E0 (VLAN300) and the 2651XM's interface Fa0/1 is configured for the same vlan as all connecting clients and the PIX515E's E1 (VLAN10). Hope this makes sense.
What kind of tools/commands can be run on each device (Vista client, 3560G, PIX515E, 2651XM) to find out what is causing this issue?