My setup is cable modem->Palo Alto Networks 200 FW->Juniper EX2200 main switch. Data line is 20 down, 4 up. I have successfully setup a site to site tunnel with an offsite vendor. If the tunnel is not up, and only inet traffic is flowing, ping times are very low, and there is no packet loss. If I bring the tunnel up, but run only ping traffic across it, ping times are still low, and there is no packet loss. As soon as I begin to run "real" traffic across the tunnel (traffic in question is Mimix backing up our iSeries server to the offsite vendor), I get bad packet loss to the internet - in the 24%-35% range, and ping times go through the roof. It makes the internet all but unusable, and no one from outside can get to our internal web facing sites.
I thought perhaps that I was running into my upload bandwidth cap, but even with rate limiting on the tunnel, I am still seeing significant packet loss. The ISP observed that signal loss and line noise goes up when the tunnel is traffic traverses the tunnel. Resource/CPU usage look fine on the firewall and main switch, and I'm pretty stumped at this point. Cable modem issue perhaps? Any insights would be greatly appreciated!