Provision of deterministic services for voice over IP using priority queues

This paper discusses an approach for resource allocation and management in IP networks, particularly in the context of IP telephony. We show that it is possible to provide deterministic real time services without substantial changes to the current Internet infrastructure using static priority scheduling. All IP telephony traffic is mapped to (unidirectional) virtual channels that allow simple aggregation schemes and subdivision in two parts. We present a calculus to compute the effective bandwidth needed to serve reviewed by simulations. It is used for access control purposes and has the benefit that is can be applied to each node of a network not depending on the other nodes. The virtual channels can logically be subdivided in two parts. Thus, signaling does not need to run from one end to the other, but from both ends simultaneously to the point of aggregation in between. It is shown that the approach can fulfill the requirements of a network build from campus networks connected via a backbone network

Towards Provisioning Diffserv Intra-Nets

The question of our study is how to provision a diffserv (differentiated service) intra-net serving three classes of traffic, i.e., voice, real-time data (e.g. stock quotes), and best-effort data. Each class of traffic requires a different level of QoS (Quality of Service) guarantee. For VoIP the primary QoS requirements are delay and loss; for real-time data response-time. Given a network configuration and anticipated workload of a business intranet, we use ns-2 simulations to determine the minimum capacity requirements that dominate total cost of the intra-net. To ensure that it is worthwhile converging different traffic classes or deploying diserv, we cautiously examine capacity requirements in three sets of experiments: three traffic classes in i) three dedicated networks, ii) one network without diffserv support, and iii) one network with diffserv support. We find that for the business intra-net of our study, integration without diffserv may need considerable over-provisioning depending on the fraction of real-time data in the network. In addition, we observe significant capacity savings in the diffserv case; thus conclude that deploying diffserv is advantageous. The relations we find give rise to, as far as we know, the first rule of thumb on provisioning a diffserv network for increasing real-time data