On the Role of Queue Length Information in Network Control

We study the role played by queue length information in the operation of flow control and server allocation policies. We first consider a simple model of a single server queue with congestion-based flow control. The input rate at any instant is decided by a flow control policy, based on the queue oc...

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Bibliographic Details
Main Authors: Jagannathan, Krishna Prasanna, Modiano, Eytan H., Zheng, Lizhong
Other Authors: Massachusetts Institute of Technology. Department of Aeronautics and Astronautics
Format: Article
Language:en_US
Published: Institute of Electrical and Electronics Engineers 2012
Online Access:http://hdl.handle.net/1721.1/69886
https://orcid.org/0000-0002-6108-0222
https://orcid.org/0000-0001-8238-8130
Description
Summary:We study the role played by queue length information in the operation of flow control and server allocation policies. We first consider a simple model of a single server queue with congestion-based flow control. The input rate at any instant is decided by a flow control policy, based on the queue occupancy. We identify a simple “two-threshold” control policy, which achieves the best possible exponential scaling for the queue congestion probability, for any rate of control. We show that when the control channel is reliable, the control rate needed to ensure the optimal decay exponent for the congestion probability can be made arbitrarily small. However, if control channel erasures occur probabilistically, we show the existence of a critical erasure probability threshold beyond which the congestion probability undergoes a drastic increase due to the frequent loss of control packets. We also determine the optimal amount of error protection to apply to the control signals by using a simple bandwidth sharing model. Finally, we show that the queue length based server allocation problem can also be treated using this framework and that the results obtained for the flow control setting can also be applied to the server allocation case.