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Perspective Access Networks Perspective Access Networks The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Goodell, Geoffrey Lewis. 2006. Perspective Access Networks. Harvard Computer Science Group Technical Report TR-12-06. Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:34310066 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Other Posted Material, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#LAA Perspective Access Networks Geoffrey Lewis Goodell TR-12-06 Computer Science Group Harvard University Cambridge, Massachusetts Perspective Access Networks A dissertation presented by Geoffrey Lewis Goodell to The Division of Engineering and Applied Sciences in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the subject of Computer Science Harvard University Cambridge, Massachusetts July 2006 to my mother, Elaine c 2006 - Geoffrey Lewis Goodell All rights reserved. Thesis advisor Author Mema Roussopoulos Geoffrey Lewis Goodell Perspective Access Networks Abstract Perspective Access Networks provide an infrastructure from which users can spec- ify the location from which they wish to view the Internet. The ability to specify location has become necessary as the Internet has become increasingly inconsistent. An increasing preponderance of middleboxes, location-dependent services, and large- scale content filtering have contributed to this situation. Our work offers the following contributions. First, we propose an infrastructure that routes traffic to a location from which a given resource can be viewed, taking instructions from user-specified attributes describing the desired location. Second, we analyze the tradeoff between the expressivity of user requests and the finite resources available within the network for propagating metadata about available perspectives. Third, we stipulate a set of real scenarios that fall within the limits of what can reasonably be handled by a system appropriately tuned to manage the tradeoff, and we argue that the specific algorithm we propose can handle the scenarios effectively. Contents Title Page . i Abstract . iii Table of Contents . iv List of Figures . viii List of Tables . xiv Acknowledgments . xvi 1 Introduction 1 1.1 Motivation . 4 1.1.1 Fragmentation Defined . 5 1.1.2 Causes of Fragmentation . 8 1.2 End-To-End System Design . 19 1.3 Addressing Fragmentation . 21 1.3.1 Primary Contributions . 23 1.3.2 A “Coreless” Internet . 25 1.3.3 Contrasting PAN and VPN . 26 1.4 High-Level System Overview . 28 1.4.1 Components . 28 1.4.2 Accessing Resources . 29 1.4.3 Directory Functionality . 31 1.5 Design Considerations . 34 1.5.1 Objectives . 35 1.5.2 Tradeoffs . 40 1.6 Outline . 42 2 Related Work 44 2.1 Routing . 46 2.1.1 Interdomain Routing . 46 2.1.2 Overlay Routing . 48 2.2 Indirection . 49 2.2.1 Internet Indirection Infrastructure . 49 iv Contents v 2.2.2 TRIAD . 50 2.3 Interoperating with Middleboxes . 51 2.3.1 Host Identity Protocol . 52 2.3.2 Delegation-Oriented Architecture . 53 2.3.3 Unmanaged Internet Protocol . 55 2.3.4 IPNL . 56 2.4 Decoupling Policy from Mechanism . 57 2.4.1 FARA/NewArch . 57 2.4.2 Platypus . 58 2.5 Anonymity Networks . 60 2.5.1 Tor................................. 61 2.5.2 ANON . 64 2.6 Covert Communication . 65 2.6.1 Psiphon . 65 2.6.2 Infranet . 66 2.7 Embracing Heterogeneity . 66 2.7.1 Semantic-Free Referencing . 67 2.7.2 Plutarch . 69 2.8 Distributed Directories . 69 2.8.1 Domain Name System . 70 2.8.2 Filesharing Networks . 70 2.8.3 Cooperative Web Caching . 71 3 Network Architecture 73 3.1 Design Challenges . 74 3.1.1 Infrastructure Components . 76 3.1.2 Forwarding Traffic . 82 3.1.3 Privacy . 87 3.1.4 Identification of Resources . 90 3.1.5 Separation of Roles . 93 3.1.6 Control Plane . 94 3.2 Deployment Challenges . 96 3.2.1 Resource Discovery . 97 3.2.2 Network Arrangement . 99 3.2.3 Forwarder Discovery . 101 3.2.4 Unidirectional Links . 101 3.2.5 Namespace Collisions . 102 3.3 Managing Perspectives . 103 3.3.1 Defining Perspectives . 104 3.3.2 Selecting Perspectives . 107 3.4 Implementation (Blossom) . 109 3.4.1 Transport Layer Requirements . 110 Contents vi 3.4.2 Integrating Blossom and Tor . 112 3.4.3 Advertising Perspectives . 114 3.4.4 Transport Layer Interface . 117 3.5 Authentication . 121 3.6 Practical Applications . 125 3.6.1 Circuits with Multiple Forwarders . 126 3.6.2 Routing . 129 4 Directory Service 133 4.1 Directory Architecture . 135 4.1.1 Master Records . 136 4.1.2 Directory Records . 137 4.1.3 Forwarder Records . 141 4.1.4 Client Interaction . 143 4.1.5 Directory Protocol . 147 4.2 Design Tradeoffs . 152 4.2.1 Structured versus Unstructured . 153 4.2.2 Propagating Forwarder Information . 154 4.2.3 Responding to Queries . 158 4.2.4 Repeated Queries and Circuit Length . 159 4.3 Configuration . 161 4.3.1 Filtering and Aggregation . 161 4.3.2 Peering Arrangements . 162 4.3.3 Propagation of Perspectives . 167 4.4 Policy Framework . 168 4.4.1 Modifications to RPSL . 169 4.4.2 Examples . 173 4.5 Dynamic Learning . 177 4.5.1 Exponential Problem in Managing Perspectives . 177 4.5.2 Hysteresis Approach . 179 4.5.3 Algorithm . 184 5 Evaluation 190 5.1 Client Performance . 191 5.1.1 Circuit Setup . 192 5.1.2 Data Plane . 197 5.2 Directory Performance . 201 5.2.1 Infrastructure Performance . 201 5.2.2 Traffic Profiles . 208 5.2.3 Comparison to Interdomain Routing . 211 5.3 Deployability and Incentives . 214 5.3.1 Aggregation Strategies . 215 Contents vii 5.3.2 Resource Management Strategies . 221 5.4 Usefulness of Perspective Access Networks . 225 5.4.1 Essential Applications . 225 5.4.2 Security Considerations . 228 5.5 Scalability . 231 5.5.1 Case Study: Political Filtering . 231 5.5.2 Concrete Example . 236 5.6 Determining Attribute Categories . 240 6 Conclusion 244 6.1 Principal Contributions . 245 6.2 Misuse of Location Information . ..
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