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Offered Load (offered + load)
Selected AbstractsGeneralized window advertising for TCP congestion control,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 6 2002Mario Gerla Congestion in the Internet is a major cause of network performance degradation. The Generalized Window Advertising (GWA) scheme proposed in this paper is a new approach for enhancing the congestion control properties of TCP. GWA requires only minor modifications to the existing protocol stack and is completely backward compatible, allowing GWA-hosts to interact with non-GWA hosts without modifications. GWA exploits the notion of end-host-network cooperation, with the congestion level notified from the network to end hosts. It is based on solid control theory results mat guarantee performance and stable network operation. GWA is able to avoid window oscillations and the related fluctuations in offered load and network performance. This makes it more robust to sustained network overload due to a large number of connections competing for the same bottleneck, a situation where traditional TCP implementations fail to provide satisfactory performance. GWA-TCP is compared with traditional TCP, TCP with RED and also ECN using the ns-2 simulator. Results show that in most cases GWA-TCP outperforms the traditional schemes. In particular, when compared with ECN, it provides smoother network operation and increased fairness. [source] A distributed adaptive guard channel reservation scheme for cellular networksINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 9 2007H.K. Pati Abstract In this paper, a distributed adaptive guard channel reservation (DAGCR) scheme is proposed to give priority to handoff calls. This scheme is built upon the concept of guard channels and it uses an adaptive algorithm to search automatically the optimal number of guard channels to be reserved at each base station. The quality-of-service (QoS) parameters used are the new and handoff call blockings. Simulation studies are performed to compare the present algorithm with the static guard channel policy. Simulation results show that this proposed algorithm guarantees the handoff call blocking probability to remain below the targeted threshold up to a substantially high offered load with a minimal blocking to new calls up to a moderate offered load and also shows significantly high channel utilization in all offered load conditions. This scheme is examined over a wide range of offered load. Thus, it seems the proposed scheme is very useful in controlling the blocking performances in wireless cellular networks. Copyright © 2006 John Wiley & Sons, Ltd. [source] On Estimation in M/G/c/c QueuesINTERNATIONAL TRANSACTIONS IN OPERATIONAL RESEARCH, Issue 6 2001Mei Ling Huang We derive the minimum variance unbiased estimator (MVUE) and the maximum likelihood estimator (MLE) of the stationary probability function (pf) of the number of customers in a collection of independent M/G/c/c subsystems. It is assumed that the offered load and number of servers in each subsystem are unknown. We assume that observations of the total number of customers in the system are utilized because it may be impractical or impossible to observe individual server occupancies. Both estimators depend on the R distribution (the distribution of the sum of independent right truncated Poisson random variables) and R numbers. [source] | ||||||||||