This control can be accomplished in many ways and for many reasons; however traffic shaping is always achieved by delaying packets.
Shaping is widely used for teletraffic engineering, and appears in domestic ISPs' networks as one of several Internet Traffic Management Practices (ITMPs).
[7] Some ISPs may use traffic shaping to limit resources consumed by peer-to-peer file-sharing networks, such as BitTorrent.
[8] Data centers use traffic shaping to maintain service level agreements for the variety of applications and the many tenants hosted as they all share the same physical network.
Nodes in an IP network which buffer packets before sending on a link which is at capacity produce an unintended traffic shaping effect.
Metered packets or cells are then stored in a FIFO buffer, one for each separately shaped class, until they can be transmitted in compliance with the associated traffic contract.
Transmission may occur immediately (if the traffic arriving at the shaper is already compliant), after some delay (waiting in the buffer until its scheduled release time) or never (in case of packet loss).
Traffic shaping is thus a good means for companies to avoid purchasing additional bandwidth while properly managing these resources.
Traffic shaping defines bandwidth rules whereas application acceleration using multiple techniques like a TCP performance-enhancing proxy.
WAN optimization, on the other hand, compresses data streams or sends only differences in file updates.