An Analytical Model for Torus Networks in the Presence of Batch Message Arrivals with Hot-spot Destinations

Interconnection networks are hardware fabrics supporting communications between individual processors in multi- computers. The low-dimensional k-ary n-cubes （or torus） with adaptive wormhole switching have attracted significant research efforts to construct high-performance interconnection networks in contemporary multi-computers. The arrival process and destination distribution of messages have great effects on network performance. With the aim of capturing the characteristics of the realistic traffic pattern and obtaining a deep understanding of the performance behaviour of interconneetion networks, this paper presents an analytical model to investigate the message latency in adaptive-routed wormhole-switched torus networks where there exists hot-spot nodes and the message arrivals follow a batch arrival process. Each generated message has a given probability to be directed to the hot-spot node. The average degree of virtual channel multiplexing is computed by the GE/G/1/V queueing system with finite buffer capacity. We compare analytical results of message latency with those obtained through the simulation experiments in order to validate the accuracy of the derived model.

On the Performance of Traffic Locality Oriented Route Discovery Algorithm with Delay

In MANETs, traffic may follow certain pattern that is not necessarily spatial or temporal but rather to follow special needs as a part of group for collaboration purposes. The source node tends to communicate with a certain set of nodes more than others regardless of their location exhibiting traffic locality where this set changes over time. We introduce a traffic locality oriented route discovery algorithm with delay, TLRDA-D. It utilises traffic locality by establishing a neighbourhood that includes the most likely destinations for a particular source node. The source node broadcasts the route request according to the original routing used. However, each intermediate node broadcasts the route request with a delay beyond this boundary to give priority for route requests that are travelling within their own source node’s neighbourhood region. This ap-proach improves the end-to-end delay and packet loss, as it generates less contention throughout the network. TLRDA-D is analysed using simulation to study the effect of adding a delay to route request propagation and to decide on the amount of the added delay.