Internetworking circuit and connectionless networks
ICACT'09 Proceedings of the 11th international conference on Advanced Communication Technology - Volume 1
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There is an increasing interest in optical connection-oriented networks to support the high-speed and predictable-service requirements of applications used in the scientific research community. Various experimental testbeds have been created. One area of networking research in these testbed projects is dynamic bandwidth sharing because the number of universities and national research laboratories involved in these scientific projects is large enough to make the use of dedicated circuits (leased lines) prohibitively expensive. We propose two new bandwidth-sharing mechanisms, both of which are book-ahead (BA) reservation schemes for high-speed connection-oriented networks. First, we define two types of reservation requests: (i) session-type requests, which specify the required bandwidth and duration, and (ii) data-type requests, which specify the amount of data to be transferred. For session-type requests, we propose two variants: a BA-n scheme, in which a user specifies n acceptable call-initiation time options, and a BA-First scheme, in which a user accepts any call-initiation time. We construct two novel analytical models for these two variants of BA schemes. Using the analytical and simulation models, we show that BA schemes overcome the limitation of the immediate-request (IR) mechanism, making it feasible to support applications even when the per-call bandwidth is large relative to link capacity. Our second book-ahead mechanism called Varying-Bandwidth Delayed Start (VBDS) is for data-type (file transfer) requests. By having applications specify file sizes in their reservation requests, a VBDS scheduler is able to assign a varying-bandwidth allocation for different time ranges instead of a single fixed-rate. Through simulations, we show that this approach improves system performance when compared to fixed-bandwidth schemes significantly. As a complement to the analytical and simulation studies used in the design of our two proposed BA schemes, we undertake an implementation and experimental study of the IR bandwidth-sharing mode in high-speed connection-oriented networks. We deployed a three-node connection-oriented network called CHEETAH, and implemented a software package to support the IR bandwidth-sharing mode in this network. We obtain measurements for end-to-end circuit setup delays and per-switch signaling message processing delays. These measurements are useful for analytical and simulation studies of connection-oriented networks, and in network design and configurations.