Honeywell Aerospace

Integrated Services (IntServ) and Differentiated Services (DiffServ) are two of the current approaches to provide Quality of Service (QoS) guarantees in the next generation Internet. IntServ aims at providing guarantees to end applications (individual connections) which gives rise to scalability issues in the core of the network. On the contrary, DiffServ is designed to provide QoS to aggregates, and does not suffer from scalability. It is therefore, believed that the combination of IntServ at the edge and DiffServ at the core will be able to provide QoS guarantees to end applications.1, 2 Although there have been several proposals on how to perform mapping of services between IntServ and DiffServ, there hasn’t been any study to quantitatively show the level of QoS that can be achieved when the two networks are connected. The objective of this paper is to quantitatively demonstrate the QoS guarantees that can be obtained by end applications when IntServ is run over DiffServ. We have used goodput, drop ratio and non-conformant ratio of packets from the different services and the queue size of DiffServ router to determine the QoS obtained by packets belonging to different traffic classes