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Edwards Air Force Base, United States

Fecko M.,Applied Communication science | Chang K.,Applied Communication science | Cichocki A.,Applied Communication science | Wong L.,Applied Communication science | And 4 more authors.
Proceedings of the International Telemetering Conference | Year: 2015

We developed priority-aligned flow control between the queuing system and the radio for IPbased telemetry systems. The approach provides the unified flow control across all nodes and traffic classes in telemetry links to better regulate bandwidth usage without creating oscillations. It combines multiple features: Volume-based flow control ensures consistency between a traffic queue's drain rate and the TDMA slot allocations for this queue. The allocations are translated into the number of packets to be sent to the radio from the router for each QoS class and test mission. In the case of iNET, the necessary capacity allocations are provided by the Link Manager on the ground. Fine-grained queue management allows flow control algorithms to adjust dynamically multiple parameters at the Traffic Engineering Queues as needed. Router-radio interface enhances the existing IETF standard Data Link Exchange Protocol (DLEP) to provide the signaling required for our solution. We defined the queue throughput shortage as the key evaluation metric. Our approach performed significantly better in comparison with the coarse-grained queue control available in Linux kernel. When averaged across links/queues, the reduction was 2-6% and 4-28% for high (8Mbps) and low (1Mbps) channel capacities, respectively. When averaged across multiple channel capacities, the maximum per-queue shortage was reduced from 47% to 4.5%. Source


Fecko M.,Applied Communication science | Chang K.,Applied Communication science | Cichocki A.,Applied Communication science | Kim H.,Applied Communication science | And 11 more authors.
Proceedings of the International Telemetering Conference | Year: 2014

In an iNET telemetry network, Link Manager (LM) dynamically allocates capacity to radio links to achieve desired QoS guarantees. Under the T&E S&T iMANPOL program, we developed an enhanced capacity allocation algorithm that can better cope with severe congestion and misbehaving users and traffic flows. We compare the E-LM with the LM baseline algorithm (B-LM), which employs priority-weighted allocation. The B-LM is expected to perform well for the majority of traffic patterns, but does not prevent an ill-behaved traffic class from causing excessive latency on other radio links. The E-LM ensures that each class has a "guaranteed" portion of the total available bandwidth that is proportional to the weight of the class. If the traffic loading of a class is lower than its quota, the difference can be flexibly shared by other classes across multiple links. If the traffic loading of a class is higher than its quota, its demand may still be satisfied, provided that the capacity is not taken away from well-behaved traffic classes that stay below their quotas. The qualitative analysis shows the E-LM provides lower latencies for the well-behaved links in overloading conditions and increases the overall system throughput when the traffic is unbalanced. We conducted extensive experiments to confirm that analysis, with the E-LM reducing latency of well-behaved flows up to 90%, and increasing overall throughput up to 65% over the B-LM. Source

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