Conclusions and Outlook

Abstract

The major conclusion that can be drawn from this book is that accepting heterogeneity with regard to network QoS provision as a fact or even a design principle of large-scale internetworks allows to achieve more generic and efficient solutions to interworking problems between heterogeneous network QoS systems. As presented in the preceding chapters, we have shown this for several areas of interworking (an illustrative summary of these is given in Figure 68). Therefore, we argue for a more ambitious and fundamental approach towards interworking of heterogeneous network QoS systems. Much of the existing work in heterogeneous network QoS systems has been focussing on easy-to-implement ad hoc solutions for the interworking of specific pairs of network QoS systems. This yielded rather inefficient and non-reusable results from our point of view. The underlying assumption of this work has been that such interworking solutions are only of a temporary character, and thus need not be dealt with in the most careful way. However, if one accepts our arguments for internetwork QoS being inherently heterogeneous, then such an approach can no longer be adhered to, but a more fundamental approach towards the interworking of heterogeneous network QoS systems is required. The phenotype approach presented and followed in this book is an attempt at such a fundamental treatment of interworking between heterogeneous network QoS systems. It has allowed us to first concentrate on those issues which promise the highest potential to be dealt with generically and then advance to problems which are strongly linked to Qos technologies and can therefore not be dealt with in an absolutely generic fashion.