Traffic shaping is needed when the circuit size is smaller than the interface speed, or with frame relay when the hub port size is larger than the remote site port. An example would be a 100mb interface connecting to an ISP who is limiting you to 10mb end to end. Traffic shaping would smoothly feed out the packets at a 10mb rate, and allow the router to queue packets exceeding the rate. The queuing could be weighted fair, FIFO, or CBWFQ. Without traffic shaping the router would send at a 100mb rate, and the ISP would throw away any packets over 10mb.
So if your bandwidth is 100mb, and your interface is 100mb,you do not need traffic shaping for your 10mb class. If you have less bandwidth, traffic shaping and CBWFQ can be used together.
