The Pennsylvania State University The Graduate School School of Science, Engineering, and Technology CAFFEINE: CONGESTION AVOIDANCE FOR FAIRNESS & EFFICIENCY IN NETWORK ENTITIES A Thesis in Computer Science by Pattanapoom Phinjirapong ©2015 Pattanapoom Phinjirapong Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science August 2015 ii The thesis of Pattanapoom Phinjirapong was reviewed and approved* by the following: Jeremy J. Blum Associate Professor of Computer Science Thesis Advisor Thang N. Bui Associate Professor of Computer Science Chair, Mathematics and Computer Science Programs Sukmoon Chang Associate Professor of Computer Science Omar El Ariss Assistant Professor of Computer Science Linda M. Null Associate Professor of Computer Science Associate Chair, Mathematics and Computer Science Programs *Signatures are on file in the Graduate School. iii Abstract Software Defined Networking (SDN) enables the separation of the data forwarding plane and the control plane in network switches and routers. The control plane functionality is provided by a centralized network operating system. By moving this functionality to software, a range of new capabilities are possible in networks. This thesis describes and evaluates a new algorithm, called Congestion Avoidance For Fairness & Efficiency In Network Entities (CAFFEINE) that uses SDN provided capabilities. CAFFEINE provides dynamic routing in network topology for long-lived network traffic with goals of fully utilizing network capacity and maintaining fairness among traffic classes through Quality of Service (QoS) guarantees. CAFFEINE is designed to spread these long-lived traffic flows throughout an organization’s network. To achieve the goals, CAFFEINE periodically polls network devices in order to monitor the current network state. CAFFEINE routes traffic using a modified widest path algorithm, with path length constraints, to find a path in the network with maximum available bandwidth, and then it sets QoS guarantees on that path. From a service view, CAFFEINE consists of a network monitoring service, a rate limiting service, a queue management service, and a flexible routing service. The network monitoring service is responsible for polling the state of the network from the controller in SDN and calculating aggregate information. The flexible routing service periodically receives the aggregated network state information and re-calculates the new routes. The rate limiting service also receives that network state information and uses this state to set a minimum guaranteed bandwidth and a maximum allowed bandwidth for every class of traffic on each output port of every router in the topology. The queue management service then sets rules in the network switches to assign the new flow to a particular path in the network. The evaluation of CAFFEINE is simulated on virtual networks using Mininet, virtualization software that can simulate hosts and switches. The testing compares CAFFEINE against a conventional routing scheme that uses shortest path routing. Multiple tests, which represent variety of networks, show that CAFFEINE is able to utilize network spare capacity and can prioritize network flows from preconfigured rules. CAFFINE allows network administrators to categorize different flows to different priorities for weighted fairness and gain better throughput. iv Table of Contents List of Figures ............................................................................................................................................................................. v List of Tables ............................................................................................................................................................................. vi List of Algorithms .................................................................................................................................................................. vii Chapter 1: Introduction ........................................................................................................................................................ 1 Chapter 2: Preliminaries ....................................................................................................................................................... 4 2.1 Introduction ................................................................................................................................................................... 4 2.2 Shortest Path Uniform Routing ............................................................................................................................. 4 2.3 Pre-SDN Alternate Approaches ............................................................................................................................. 5 2.4 SDN Approaches .......................................................................................................................................................... 5 Chapter 3: Methodology ..................................................................................................................................................... 10 3.1 Overview of CAFFEINE ........................................................................................................................................... 10 3.2 CAFFEINE Network Services ................................................................................................................................ 11 3.2.1 Network Monitoring Service ........................................................................................................................ 13 3.2.2 Rate Limiting Service ...................................................................................................................................... 14 3.2.3 Flexible Routing Service ................................................................................................................................. 21 3.2.4 Queue Management Service ......................................................................................................................... 23 Chapter 4: Evaluation .......................................................................................................................................................... 24 4.1 Simulation System .................................................................................................................................................... 24 4.1.1 Assumptions ....................................................................................................................................................... 24 4.1.2 Simulation Details ............................................................................................................................................. 24 4.1.3 Fairness Testing ................................................................................................................................................ 26 4.1.4 Utilization Testing ............................................................................................................................................ 30 4.1.5 Variable Link Capacity Testing .................................................................................................................... 35 Chapter 5: Conclusions and Future Work ................................................................................................................... 39 5.1 Evaluation of CAFFEINE ......................................................................................................................................... 39 5.2 Future Work ................................................................................................................................................................ 39 References ................................................................................................................................................................................ 41 v List of Figures Figure 1: Data flow diagram of CAFFEINE .................................................................................................................. 12 Figure 2: Example scenario of weighted fairness .................................................................................................... 18 Figure 3: Example scenario for minimizing wasted effort ................................................................................... 19 Figure 4: The topology of fairness testing ................................................................................................................... 26 Figure 5: Comparison graph of downloaded data in fairness testing .............................................................. 27 Figure 6: Comparison graph of total downloaded data in fairness testing ................................................... 27 Figure 7: Comparison of average bandwidth in fairness testing ....................................................................... 28 Figure 8: The topology of utilization testing .............................................................................................................. 30 Figure 9: Comparison of possible paths for h1, h2 and h3 ................................................................................... 30 Figure 10: Comparison of possible paths for h4, h5 and h6 ................................................................................ 31 Figure 11: Comparison of possible paths for h7, h8