att_abstract={{Virtualized cloud-based services can take advantage of statistical
multiplexing across applications to yield significant cost savings. However, achieving similar savings with real-time services can be a challenge. In this paper, we seek to lower a provider's costs for real-time IPTV services through a virtualized IPTV architecture and through intelligent time-shifting of selected services.

Using Live TV and Video-on-Demand (VoD) as examples, we show that we can
take advantage of the different deadlines associated with each service to effectively multiplex these services.  We provide a generalized framework for computing the amount of resources needed to support multiple services, without missing the deadline for any service. We construct the problem as an optimization formulation that uses a generic cost function. We consider multiple forms for the cost function (e.g., maximum, convex and concave functions) reflecting the cost of providing the service. The solution to this formulation gives the number of servers needed at different time instants to support these services. We implement a simple mechanism for time-shifting scheduled jobs in a simulator and study the reduction in server load using real traces from an operational IPTV network. Our results show that we are able to reduce the load by $sim24\%$ (compared to a possible $sim31.3\%$ as predicted by the optimization framework). We also show that there are interesting open problems in designing mechanisms that allow time-shifting of load in such environments.}},
	att_authors={va037f, vg7777, rj2124, kr2812, vv9482},
	att_copyright_notice={{This version of the work is reprinted here with permission of IEEE for your personal use. Not for redistribution. The definitive version was published in 2012. {{, 2013-01-01}}
	author={Vaneet Aggarwal and Vijay Gopalakrishnan and Rittwik Jana and Kadangode Ramakrishnan and Vinay Vaishampayan},
	institution={{Special Issue of IEEE Transactions on Multimedia: Cloud-Based Mobile Media: Infrastructure, Services}},
	title={{Optimizing Cloud Resources for Delivering IPTV Services through Virtualization}},