Optimization of network resource allocation for software-defined data center networks

As cloud computing and data center network flourishes, the network that was once designed to support traditional networking scenario must now satisfy new requirements to suit for the cloud environment and increasing demands. The Software-Defined Networking (SDN) paradigm, with the control plane separated from the data plane, is widely regarded as the next generation networking technique. The objective of this thesis is to optimize network resources allocation in the software-defined data center networks (DCN). The SDN resources considered here are the SDN switch to controller link bandwidth and the switch flow table size. First, a queueing model is developed to provision the SDN switches with an appropriate number of switch-to-controller connections. Second, a controller-level admission control mechanism is proposed to determine if a new flow should be admitted to the network when the flow table is congested. Third, we study the fair and high-satisfaction resources allocation problem with the routing path optimized in software-defined DCN. The delay guarantees for delay-sensitive flows are also provided. Finally, some practical issues are considered for the resources allocation algorithms. The provided theoretical analysis and simulation results in this dissertation improve the efficiency of resource allocation in software-defined DCN.Ph.D

QuickCast: Fast and Efficient Inter-Datacenter Transfers using Forwarding Tree Cohorts

Large inter-datacenter transfers are crucial for cloud service efficiency and are increasingly used by organizations that have dedicated wide area networks between datacenters. A recent work uses multicast forwarding trees to reduce the bandwidth needs and improve completion times of point-to-multipoint transfers. Using a single forwarding tree per transfer, however, leads to poor performance because the slowest receiver dictates the completion time for all receivers. Using multiple forwarding trees per transfer alleviates this concern--the average receiver could finish early; however, if done naively, bandwidth usage would also increase and it is apriori unclear how best to partition receivers, how to construct the multiple trees and how to determine the rate and schedule of flows on these trees. This paper presents QuickCast, a first solution to these problems. Using simulations on real-world network topologies, we see that QuickCast can speed up the average receiver's completion time by as much as $10\times$ while only using $1.04\times$ more bandwidth; further, the completion time for all receivers also improves by as much as $1.6\times$ faster at high loads.Comment: [Extended Version] Accepted for presentation in IEEE INFOCOM 2018, Honolulu, H

Portfolios of Exchange Relationships: An Empirical Investigation of an Online Marketplace for IT Services

Small firms face distinct problems and opportunities when procuring IT resources. Whereas previous work focused at the level of firm or buyer-supplier dyad, we address portfolios of buyer-supplier relationships at an online marketplace for IT services. Using the portfolio approach, we develop a buyers taxonomy and analyze properties of resulting clusters.Our investigation reveals four clusters of buyers with distinct mixes of long-term and short-term supplier relationships. Although reverse auctions are found to be associated with short-term relationships and negotiations support long-term relationships, buyers in different clusters use the two mechanisms in combination to a different extent.Performance;Buyer-supplier relationships;IT services;Online markets;Outsourcing;Reverse auctions

Performance Evaluation - Annual Report Year 3

This report describes the work done and results obtained in third year of the CATNETS project. Experiments carried out with the different configurations of the prototype are reported and simulation results are evaluated with the CATNETS metrics framework. The applicability of the Catallactic approach as market model for service and resource allocation in application layer networks is assessed based on the results and experience gained both from the prototype development and simulations. --Grid Computing