IP Convergence: Beyond VoIP, Beyond Cost Savings

As was stated, theoretically you could set the port ranges into the ACL and assign the TOS bit accordingly. Now we are talking about your RAS connection to Global Crossing's corporate network so even if you set the forward path and your service provider doesn't remark the packets, you will still have a forward/return path issue as the traffic is not traversing the service provider's network as priority. Also the return path isn't going to be marked as priority across GX's network (unless it is already tagged that way, I am not in GIS).

So yes, I agree, it is not looking good.