{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/105636"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/105636","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Privacy-preserving network congestion control","abstract":"Cyber-physical technology is applied in various domains and connect computation with physical processes. Distributed cyber-physical networks have had a major impact in the area of networking and communications, more specifically on the Internet. The Internet nowadays is an important tool of communication, however one of the main challenges facing users on the Internet is maintaining privacy, especially when facing widespread surveillance. Anonymity networks have emerged as a solution to this problem by allowing users to conceal their identities online. The most successful anonymous communications network to date is currently the Tor network. It is operated by volunteers around the world and has many users worldwide. However, the trade off between performance and anonymity has always been a major problem for this type of networks. Users' traffic in Tor is routed across a series of servers; each user's path going through the network transits three of them. This process of path selection creates a load balancing problem that could lead to network congestion. Congestion may deteriorate the network performance and service quality resulting in queuing delay, data packet loss and the blocking of new connections. In this work, we study the problem of load-balancing in path selection in anonymous networks such as Tor. We first find that the current Tor path selection strategy can create significant imbalances. We then develop a (locally) optimal algorithm for selecting paths and show, using flow-level simulation, that it results in much better balancing of load across the network. Our initial algorithm uses the complete state of the network, which is impractical in a distributed setting and can compromise users' privacy. We therefore develop a revised algorithm that relies on a periodic and differentially private summary of the network state to approximate the optimal assignment. Our simulations show that the revised algorithm significantly outperforms the current strategy while maintaining provable privacy guarantees.","abstract_html":"Cyber-physical technology is applied in various domains and connect computation with physical processes. Distributed cyber-physical networks have had a major impact in the area of networking and communications, more specifically on the Internet. The Internet nowadays is an important tool of communication, however one of the main challenges facing users on the Internet is maintaining privacy, especially when facing widespread surveillance. Anonymity networks have emerged as a solution to this problem by allowing users to conceal their identities online. The most successful anonymous communications network to date is currently the Tor network. It is operated by volunteers around the world and has many users worldwide. However, the trade off between performance and anonymity has always been a major problem for this type of networks. Users' traffic in Tor is routed across a series of servers; each user's path going through the network transits three of them. This process of path selection creates a load balancing problem that could lead to network congestion. Congestion may deteriorate the network performance and service quality resulting in queuing delay, data packet loss and the blocking of new connections. In this work, we study the problem of load-balancing in path selection in anonymous networks such as Tor. We first find that the current Tor path selection strategy can create significant imbalances. We then develop a (locally) optimal algorithm for selecting paths and show, using flow-level simulation, that it results in much better balancing of load across the network. Our initial algorithm uses the complete state of the network, which is impractical in a distributed setting and can compromise users' privacy. We therefore develop a revised algorithm that relies on a periodic and differentially private summary of the network state to approximate the optimal assignment. Our simulations show that the revised algorithm significantly outperforms the current strategy while maintaining provable privacy guarantees.","abstract_has_math":false,"creators":["Darir, Hussein"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Mechanical Engineering","degree_department":null,"school":null,"contributors":["Dullerud, Geir"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019-11-26T20:33:48Z","date_published":"2019-11-26T20:33:48Z","updated_at":"2026-07-22T22:24:44Z","subjects":["Cyber-physical","Distributed cyber-physical networks","networking","communication","Internet","Privacy","Anonymity","Tor network","Congestion","load-balancing","Path selection","differential-privacy"],"languages":["en"],"rights":["Copyright 2019 Hussein Darir"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/105636","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dullerud, Geir"]},{"key":"dc:creator","label":"Author","values":["Darir, Hussein"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019-11-26T20:33:48Z","2019-07-03","2019-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Mechanical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Cyber-physical","Distributed cyber-physical networks","networking","communication","Internet","Privacy","Anonymity","Tor network","Congestion","load-balancing","Path selection","differential-privacy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2019 Hussein Darir"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/105636"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Cyber-physical technology is applied in various domains and connect computation with physical processes. Distributed cyber-physical networks have had a major impact in the area of networking and communications, more specifically on the Internet. The Internet nowadays is an important tool of communication, however one of the main challenges facing users on the Internet is maintaining privacy, especially when facing widespread surveillance. Anonymity networks have emerged as a solution to this problem by allowing users to conceal their identities online. The most successful anonymous communications network to date is currently the Tor network. It is operated by volunteers around the world and has many users worldwide. However, the trade off between performance and anonymity has always been a major problem for this type of networks. Users' traffic in Tor is routed across a series of servers; each user's path going through the network transits three of them. This process of path selection creates a load balancing problem that could lead to network congestion. Congestion may deteriorate the network performance and service quality resulting in queuing delay, data packet loss and the blocking of new connections. In this work, we study the problem of load-balancing in path selection in anonymous networks such as Tor. We first find that the current Tor path selection strategy can create significant imbalances. We then develop a (locally) optimal algorithm for selecting paths and show, using flow-level simulation, that it results in much better balancing of load across the network. Our initial algorithm uses the complete state of the network, which is impractical in a distributed setting and can compromise users' privacy. We therefore develop a revised algorithm that relies on a periodic and differentially private summary of the network state to approximate the optimal assignment. Our simulations show that the revised algorithm significantly outperforms the current strategy while maintaining provable privacy guarantees.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-11-26 without embargo terms","The student, Hussein Darir, accepted the attached license on 2019-07-02 at 14:25.","The student, Hussein Darir, submitted this Thesis for approval on 2019-07-02 at 14:42.","This Thesis was approved for publication on 2019-07-03 at 16:42.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14133 on 2019-11-26 at 12:50:28","Made available in DSpace on 2019-11-26T20:33:48Z (GMT). No. of bitstreams: 2 DARIR-THESIS-2019.pdf: 1751698 bytes, checksum: a8e24300d9cb5ed1d06b17cb1dfba613 (MD5) LICENSE.txt: 4210 bytes, checksum: 6512fba46b0661379e977dda5f548d62 (MD5) Previous issue date: 2019-07-03"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Privacy-preserving network congestion control"]}]}],"canonical_facts":{"dc:contributor":["Dullerud, Geir"],"dc:creator":["Darir, Hussein"],"dc:date":["2019-11-26T20:33:48Z","2019-07-03","2019-08"],"dc:description":["Cyber-physical technology is applied in various domains and connect computation with physical processes. Distributed cyber-physical networks have had a major impact in the area of networking and communications, more specifically on the Internet. The Internet nowadays is an important tool of communication, however one of the main challenges facing users on the Internet is maintaining privacy, especially when facing widespread surveillance. Anonymity networks have emerged as a solution to this problem by allowing users to conceal their identities online. The most successful anonymous communications network to date is currently the Tor network. It is operated by volunteers around the world and has many users worldwide. However, the trade off between performance and anonymity has always been a major problem for this type of networks. Users' traffic in Tor is routed across a series of servers; each user's path going through the network transits three of them. This process of path selection creates a load balancing problem that could lead to network congestion. Congestion may deteriorate the network performance and service quality resulting in queuing delay, data packet loss and the blocking of new connections. In this work, we study the problem of load-balancing in path selection in anonymous networks such as Tor. We first find that the current Tor path selection strategy can create significant imbalances. We then develop a (locally) optimal algorithm for selecting paths and show, using flow-level simulation, that it results in much better balancing of load across the network. Our initial algorithm uses the complete state of the network, which is impractical in a distributed setting and can compromise users' privacy. We therefore develop a revised algorithm that relies on a periodic and differentially private summary of the network state to approximate the optimal assignment. Our simulations show that the revised algorithm significantly outperforms the current strategy while maintaining provable privacy guarantees.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2019-11-26 without embargo terms","The student, Hussein Darir, accepted the attached license on 2019-07-02 at 14:25.","The student, Hussein Darir, submitted this Thesis for approval on 2019-07-02 at 14:42.","This Thesis was approved for publication on 2019-07-03 at 16:42.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14133 on 2019-11-26 at 12:50:28","Made available in DSpace on 2019-11-26T20:33:48Z (GMT). No. of bitstreams: 2 DARIR-THESIS-2019.pdf: 1751698 bytes, checksum: a8e24300d9cb5ed1d06b17cb1dfba613 (MD5) LICENSE.txt: 4210 bytes, checksum: 6512fba46b0661379e977dda5f548d62 (MD5) Previous issue date: 2019-07-03"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/105636"],"dc:language":["en"],"dc:rights":["Copyright 2019 Hussein Darir"],"dc:subject":["Cyber-physical","Distributed cyber-physical networks","networking","communication","Internet","Privacy","Anonymity","Tor network","Congestion","load-balancing","Path selection","differential-privacy"],"dc:title":["Privacy-preserving network congestion control"],"dc:type":["text"],"thesis:degree_discipline":["Mechanical Engineering"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:44Z"}