iMAP Myanmar 2023 Internet Censorship Report | Page 54 Network measurements The types of network measurements that OONI collects depend on the types of tests that are run. Specifications about each OONI test can be viewed through its git repository, and details about what collected network measurements entail can be viewed through OONI Explorer or through OONI’s measurement API. In order to derive meaning from the measurements collected, OONI processes the data types mentioned above to answer the following questions: ● Which types of OONI tests were run? ● In which countries were those tests run? ● On which networks were those tests run? ● When were the tests run? ● What types of network interference occurred? ● In which countries did network interference occur? ● In which networks did network interference occur? ● When did network interference occur? ● How did network interference occur? To answer such questions, OONI’s pipeline is designed to answer such questions by processing network measurement data to enable the following: ● Attributing measurements to a specific country. ● Attributing measurements to a specific network within a country. ● Distinguishing measurements based on the specific tests that were run for their collection. ● Distinguishing between “normal” and “anomalous” measurements (the latter indicating that a form of network tampering is likely present). ● Identifying the type of network interference based on a set of heuristics for DNS tampering, TCP/IP blocking, and HTTP blocking. ● Identifying block pages based on a set of heuristics for HTTP blocking. ● Identifying the presence of “middle boxes” within tested networks. According to OONI, false positives may occur within the processed data due to a number of reasons. DNS resolvers (operated by Google or a local ISP) often provide users with IP addresses that are closest to them geographically. While this may appear to be a case of DNS tampering, it is actually done with the intention of providing users with faster access to websites. Similarly, false positives may emerge when tested websites serve different content depending on the country that the user is connecting from or when websites return failures even though they are not tampered with. Furthermore, measurements indicating HTTP or TCP/IP blocking might actually be due to temporary HTTP or TCP/IP failures; they may not conclusively be a sign of network interference. It is therefore important to test the same sets of websites across time and to cross-correlate data before reaching a conclusion on whether websites are in fact being blocked.