Vulnerability analysis of the physical part of the internet

The internet, one of the most important critical information infrastructures (CII), compasses both, the physical and cyber part. Industrial network operators and service providers often draw more attention to the protection of the cyber part. However, some recent incidents, especially those causing cascading failures and big disruptions in social functions, are reminders that physical part may be most vulnerable and deserve adequate protection efforts. Therefore, this paper put the vulnerability of the physical part of the internet in focus. Most important outage causes of the internet backbones, like cable cuts and (inter-)dependency among different networks, are presented. Analysis approaches based on network theory are introduced and applied in a case study to the Swiss research and educational network (SWITCH). Recommendations on good practices are offered finally.