Macroscopic Topology Measurements

CAIDA researchers have been collecting connectivity and latency data for a wide cross-section of the commodity Internet since 1998 for the IPv4 address space and since 2003 for the IPv6 address space. We use these data to derive maps of the Internet at various granularity levels: IP, router, AS.

The archive of raw IPv4 data and raw IPv6 data, topology measurement tools, and sample analysis code are available to the research community. The AS adjacencies derived daily from our active connectivity measurements are also available.

An analysis of Macroscopic IPv6 Topology Measurements is available.

Motivation

Topology maps of the Internet are an important tool for characterizing this critical infrastructure and understanding its properties, dynamic behavior, and evolution. They are also crucial for realistic modeling, simulation, and analysis of Internet infrastructure and other large-scale complex networks. These maps can be constructed for different layers (or granularities), e.g., fiber/copper cable, IP address, router, Points-of-Presence (PoPs), autonomous system (AS), ISP/organization. Router-level and PoP-level topology maps can powerfully inform and calibrate vulnerability assessments. ISP-level topologies, sometimes called AS-level or interdomain routing topologies (although an ISP may own multiple ASes so an AS-level graph is a slightly finer granularity) provide insights into technical, economic, policy, and security needs of the largely unregulated peering ecosystem.

CAIDA has been conducting measurements of the Internet macroscopic topology since 1998. Our tools - first skitter (1998-2008), now scamper (2007-present) have been tracking global IP level connectivity by sending probe packets from a set of source monitors to millions of geographically-distributed destinations in the IPv4 address space. Since 2003, we have been continuously probing IPv6 address space as well.

The gathered data:

characterize macroscopic connectivity and performance of the Internet,
allow various topological and geographical representations at multiple levels of aggregation granularity,
provide a valuable input for empirically-based modeling of the Internet behavior and properties,
improve situational awareness of the critical cyberinfrastructure for government agencies.

Data sources

We use two sources of data for Macroscopic Topology studies: forward Internet (IP) path information from traceroute-like active measurements and routing data from inter-domain BGP routing tables.

Active measurement data

Co-funded by DHS and NSF, we have created a powerful and versatile distributed measurement infrastructure Archipelago (Ark) that makes use of measurement nodes located in various networks worldwide and connected via the Internet to a central server at CAIDA. Ark has pioneered new features and functionality of distributed measurement infrastructure, including flexible and efficient measurement and data collection methods. Ark topology datasets (described below) available to academic researchers and government agencies via the