Several thousands of interconnected autonomous systems form the Internet, which is regarded as the most powerful communication infrastructure today. Measuring the network and monitoring its vital parameters is crucial for securing continuous availability and steady performance of the Internet. This paper introduces AS-Analyzer, a tool for gathering and analyzing data related to autonomous systems and their interconnection. Using AS-Analyzer’s modules for collecting data from different sources, calculating key figures and creating reports, we present a vivid example by analyzing the G-20’s key autonomous systems and their intermeshing. A brief discussion of key figures related to autonomous system, IPv4 addresses, connections, categories and malware will complete the presentation.