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Identifier 000443699
Title P4Debugger: tracing through network changes with table-version packet tainting
Alternative Title P4Debugger: παρακολούθηση αλλαγών δικτύου χρησιμοποιώντας προσαρμοσμένες κεφαλίδες και καταγραφή πινάκων
Author Χατζηβασιλείου, Αντώνιος Π.
Thesis advisor Δημητρόπουλος, Ξενοφώντας
Reviewer Μαγκούτης, Κωνσταντίνος
Λιάσκος, Χρήστος
Abstract The increasing consumer demands for network performance and flexibility have led enterprises to expand in Software Defined Networking (SDN). SDN is a technology that changes the way that networks work by separating the network's control logic from the underlying switches and routers, promoting centralization of network control, and introducing the ability to program the network. This allows Network administrators to use network devices and supervise them from a programmable controller. However, configuring these devices in combination with the significant growth of protocol headers increases the complexity and makes them prone to bugs. P4 is a language that works in conjunction with SDN, which expresses how packets are forwarded by the programmable network devices and have the ability to add custom headers to packets. In this thesis, we introduce P4debugger, a prototype network debugger for SDN developers which exploits the abilities of the P4. Our debugger is divided into two parts; The first part is that we taint each packet that passes through the switch with some information that allows us to backtrace them, detect loops, as well as inspect them for any policy violation. For inspecting the extra information, we use monitors that sample and analyze the packets that pass through each switch. Network administrators can preview from these monitors the behavior of the network based on the fields in the custom header of the packets. The second part of our implementation is that our controllers save the state of the flow tables before they make any changes to them. We implemented a web app to preview a visual representation of the network topology, and based on the flows the switch had at a specified time, the web app simulates its behavior. By employing this web app, the user is capable of observing the reachability as well as problems such as network loops. We evaluate our thesis by presenting three errors commonly seen by SDN programmers, which provide a solid example of how P4debugger helps a programmer find the source of the problem. Finally, we calculated the overhead that P4debugger applies to the network topology, concluding that we contribute a valuable tool to Network administrators.
Language English
Issue date 2021-11-26
Collection   School/Department--School of Sciences and Engineering--Department of Computer Science--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/b/1/4/metadata-dlib-1637056610-812738-17769.tkl Bookmark and Share
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