IPv4 Routed /24 AS Links Dataset

This dataset is useful for studying the topology of the Internet at the level of Autonomous Systems (ASes), which are approximately network(s) under a single administrative control. ASes are an important abstraction because they are the "unit of routing policy" in the routing system of the global Internet. ASes peer with each other to exchange traffic, and these peering relationships define the high-level global Internet topology. For the purposes of analysis, these peering relationships are represented with an AS graph, where nodes represent ASes and links represent peering relationships.

The IPv4 Routed /24 AS Links dataset provides regular snapshots of AS links derived from the ongoing traceroute-like IP-level topology measurements that make up our IPv4 Routed /24 Topology Dataset. We have collected this IP-level topology data since September 2007 using our next generation Archipelago (Ark) measurement infrastructure. For AS links data prior to September 2007, please see the related Skitter AS Links Dataset (skitter AS links are no longer being collected).

Data from the IPv4 Routed /24 Topology Dataset are processed by using RouteViews BGP data to identify the Autonomous System (AS) associated with each responding IP address and collapsing the original probed IP paths into a set of links between ASes. The process of converting IP addresses into Autonomous Systems involves potential distortion due to:

• No AS mapping for the IP address: some IP addresses appear in topology probes but are not advertised by any AS;
• AS Sets: an aggregated set of ASes advertises the prefix;
• Multi-origin ASes (aka MOASes): several separate ASes advertise the same prefix).

Once IP addresses have been mapped to ASes, two types of AS links can be observed: direct links, in which two adjacent IP addresses map to two different ASes, and indirect links, in which two IP addresses in different ASes are separated by one or more hops for which we could not identify an AS (because some hops were non-responding or because we were not able to identify an AS for the IP address at a given hop). Indirect links are annotated with the size of the gap between ASes as measured in IP hops.

The current AS Links dataset fixes a few bugs in the skitter-based AS-links generation software:

• The previous generation technique reported the first known link between two ASes, so if both an indirect and a direct link between the ASes was observed, and the indirect link was seen first, only an indirect link between the ASes would be reported. The new version correctly reports direct links.
• The previous software also reported the first gap size it saw for an indirect link between two ASes. Now, if an indirect link with a smaller gap size is observed, the smaller gap size is reported.

Acceptable Use Agreement

Please read the terms of the CAIDA Acceptable Use Agreement (AUA) for Publicy Accessible Datasets below:

When referencing this data (as required by the AUA), please use:

The IPv4 Routed /24 AS Links Dataset - <dates used>,
https://www.caida.org/catalog/datasets/ipv4_routed_topology_aslinks_dataset/

You are required to report your publications using this dataset to CAIDA.

Data Access

This is a legacy dataset, provided for historical purposes only. We recently made some pretty significant advances in mapping IP addresses to AS-level paths, which makes this dataset look quite inaccurate in comparison.

Instead, we encourage people to use the AS Links found in the following datasets:

1. ITDK dataset
2. AS Relationship dataset

If you have specific reasons to use this legacy AS Links dataset, you may access the legacy public CAIDA Ark IPv4 Routed /24 AS Links Dataset (September 2007-present) or access the archived public CAIDA Skitter AS Links Dataset (January 2000 - February 2008)

Topology Datasets

• Freely Available Datasets
  • The Ark IPv4 Routed /24 Topology Dataset (data older than one year only)
  • The Ark IPv4 Routed /24 DNS Names Dataset (data older than one year only)
  • IPv4 TNT MPLS Topology Dataset (data older than one year only)
  • Ark Internet Topology Data Kits (ITDK) (data older than one year only)
  • The Ark IPv6 Topology Dataset
  • The Ark IPv6 DNS Names Dataset
  • The IPv6 Routed /48 Topology Dataset
  • IPv4 Routed /24 AS Links (September 2007 - ongoing)
  • IPv6 AS Links (December 2008 - ongoing)
  • AS Rank
  • AS Relationships
  • Skitter Macroscopic Topology Data
  • Skitter Internet Topology Data Kits (ITDK) - April 2002 and April/May 2003
  • Skitter AS Links (January 2000 - February 2008)
  • Skitter Router Adjacencies
  • AS Taxonomy
  • PAM 2010 "Improving AS Annotations" Supplement
• Restricted Access Datasets
  • The Ark IPv4 Routed /24 Topology Dataset (incl. most recent one year)
  • The Ark IPv4 Routed /24 DNS Names Dataset (incl. most recent one year)
  • IPv4 TNT MPLS Topology Dataset (incl. most recent one year)
  • The Ark IPv4 Prefix-Probing Dataset (incl. most recent one year)
  • Ark Internet Topology Data Kits (ITDK) (incl. most recent one year)
  • Complete Routed-Space DNS Lookups

References

For more information on Autonomous Systems:

• RFC1930: Guidelines for creation, selection, and registration of an Autonomous System (AS)

For more information on CAIDA topology measurements, see:

• Internet Topology Data Comparison
• The Archipelago Project (Ark)
• Macroscopic Topology Measurements

For more information on topology measurements in general see:

• University of Oregon Route Views Project
• Paris traceroute