(
DIFFerentiated
SERVices) A method for adding quality of service (QoS) to IP networks from the IETF. Operating at layer 3 only, Diffserv uses the IP type of service (TOS) field as the Diffserv byte (DS byte). Diffserv does not provide traffic engineering or hard quality of service similar to ATM. When MPLS is deployed within the network, Diffserv can be used at the edge for classification and assignment to the right connection. See
MPLS.