Total Number Of Flows Research Articles

Novel dynamic delay allocation adjustment for improving bandwidth efficiency

End-to-end delay guarantees are critical to many delay-sensitive applications. To ensure such a guarantee on a flow path, the existing approaches usually statically divide its end-to-end delay requirement into per-hop delay requirements. However, such static path-level resource allocations often cause unbalanced resource reservations and bottlenecks in a network as shown in this paper, limit the total number of sessions accommodated in the network, and result in low network utilization. To address this issue, we propose a Dynamic Allocation Adjustment (DAA) approach to improve bandwidth efficiency by spreading loads over a flow path and other related links not on the path. Our simulation results show that DAA is able to significantly increase the total number of flows admitted into a network by 30% or more, compared with the best existing solution. Furthermore, it efficiently utilizes bandwidth by greatly reducing the average flow reservation at a link and the total resources reserved for a flow on its entire path.

Technique for Estimating the Number of Active Flows in High-Speed Networks

The online collection of coarse-grained traffic information, such as the total number of flows, is gaining in importance due to a wide range of applications, such as congestion control and network security. In this paper, we focus on an active queue management scheme called SRED since it estimates the number of active flows and uses the quantity to indicate the level of congestion. However, SRED has several limitations, such as instability in estimating the number of active flows and underestimation of active flows in the presence of non-responsive traffic. We present a Markov model to examine the capability of SRED in estimating the number of flows. We show how the SRED cache hit rate can be used to quantify the number of active flows. We then propose a modified SRED scheme, called hash-based two-level caching (HaTCh), which uses hashing and a two-level caching mechanism to accurately estimate the number of active flows under various workloads. Simulation results indicate that the proposed scheme provides a more accurate estimation of the number of active flows than SRED, stabilizes the estimation with respect to workload fluctuations, and prevents performance degradation by efficiently isolating non-responsive flows.

Impact of fairness on Internet performance

We discuss the relevance of fairness as a design objective for congestion control mechanisms in the Internet. Specifically, we consider a backbone network shared by a dynamic number of short-lived flows, and study the impact of bandwidth sharing on network performance. In particular, we prove that for a broad class of fair bandwidth allocations, the total number of flows in progress remains finite if the load of every link is less than one. We also show that provided the bandwidth allocation is "sufficiently" fair, performance is optimal in the sense that the throughput of the flows is mainly determined by their access rate. Neither property is guaranteed with unfair bandwidth allocations, when priority is given to one class of flow with respect to another. This suggests current proposals for a differentiated services Internet may lead to suboptimal utilization of network resources.