Maps of physical and logical Internet connectivity that are informed by and consistent with each other can expand scope and improve accuracy in analysis of performance, robustness and security. In this paper, we describe a methodology for linking physical and logical Internet maps that aims toward a consistent, cross-layer representation. Our approach is constructive and uses geographic location as the key feature for linking physical and logical layers. We begin by building a representation of physical connectivity using online sources to identify locations that house transport hardware (i.e., PoPs, colocation centers, IXPs, etc.), and approximate locations of links between these based on shortest-path rights-of-way. We then utilize standard data sources for generating maps of IP-level and AS-level logical connectivity, and graft these onto physical maps using geographic anchors. We implement our methodology in an open-source framework called the Internet Geographic Database (iGDB), which includes tools for updating measurement data and assuring internal consistency. iGDB is built to be used with ArcGIS, a geographic information system that provides broad capability for spatial analysis and visualization. We describe the details of the iGDB implementation and demonstrate how it can be used in a variety of settings.

Natural disasters can wreak havoc on Internet infrastructure. Short term impacts include impediments to first responders and long term impacts include requirements to repair or replace damaged physical components. In this paper, we present an analysis of the vulnerability of cellular communication infrastructure in the US to one type of natural disaster - wildfires. Three data sets are the basis for our study: historical wildfire records, wildfire risk projections, and cellular infrastructure deployment. We utilize the geographic features in each data set to assess the spatial overlap between historical wildfires and cellular infrastructure and to analyze current vulnerability. We find wide variability in the number of cell transceivers that were within wildfire perimeters over the past 18 years. In a focused analysis of the California wildfires of 2019, we find that the primary risk to cellular communication is power outage rather than cellular equipment damage. Our analysis of future risk based on wildfire hazard potential identifies California, Florida and Texas as the three states with the largest number of cell transceivers at risk. Importantly, we find that many of the areas at high risk are quite close to urban population centers, thus outages could have serious impacts on a large number of cell users. We believe that our study has important implications for governmental communication assurance efforts and for risk planning by cell infrastructure owners and service providers.