{'fraction_non_alphanumeric': 0.014619883040935672, 'fraction_numerical': 0.0, 'mean_word_length': 5.5807692307692305, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
ATMEN: a triggered network measurement infrastructure

Web performance measurements and availability tests have been carried out using a variety of infrastructures over the last several years. Disruptions in the Internet can lead to Web sites being unavailable or increase user-perceived latency. The unavailability could be due to DNS, failures in segments of the physical network cutting off thousands of users, or attacks. Prompt reactions to network-wide events can be facilitated by local or remote measurement and monitoring. Better yet, a distributed set of intercommunicating measurement and monitoring entities that react to events dynamically could go a long way to handle disruptions.We have designed and built ATMEN, a triggered measurement infrastructure to communicate and coordinate across various administrative entities. ATMEN nodes can trigger new measurements, query ongoing passive measurements or historical measurements stored on remote nodes, and coordinate the responses to make local decisions. ATMEN reduces wasted measurements by judiciously reusing measurements along three axes: spatial, temporal, and application.We describe the use of ATMEN for key Web applications such as performance based ranking of popular Web sites and availability of DNS servers on which most Web transactions are dependent. The evaluation of ATMEN is done using multiple network monitoring entities called Gigascopes installed across the USA, measurement data of a popular network application involving millions of users distributed across the Internet, and scores of clients to aid in gathering measurement information upon demand. Our results show that such a system can be built in a scalable fashion.