design related question

Hi there, Just want to hear your thoughts (pros and cons) on placing qos appliance between the below choke points. (a) appliance sitting between internal lan<->appliance<->dmz<->pix<->edge router<->wan cloud. or (b) appliance sitting between wan cloud<->edge router<->appliance<->dmz<->pix<->internal lan Currently this appliance supports the following qos components w/ 45mbps support on eth0 and eth1: -- shaping -- buffering -- policing Any pointers to white papers, similar deployment, lesson learned or simply your feedback will be appreciated. regards, /vicky