Hubble: Monitoring Internet Reachability in Real-Time

CSE Home

About Us

Search

Contact Info

Having trouble accessing a favorite Web site? Perhaps the site was taken offline, or the computer hosting it is down for maintenance. However, the cause could be something more mysterious. At any given moment, a portion of Internet traffic ends up being routed into information "black holes." These are situations where advertised paths exist to the destination, but messages - a request to visit a Web site, an outgoing e-mail - get lost along the way.

Hubble is a system that operates continuously to find persistent Internet black holes as they occur. Hubble has operated continuously since September 17, 2007. During that time, it identified 1,971,375 black holes and reachability problems. In the most recent quarter-hourly round, completed at 14:32 PDT, 07/30/2009, Hubble issued 6,111 traceroutes to 247 prefixes it identified as likely to be experiencing problems (of 78,772 total prefixes monitored by the system). Of these, it found 66 prefixes to be unreachable from all its vantage points and 71 to be reachable from some vantage points and not others.

Hubble is not updating at this time as we need to replace some hardware. We are sorry for the inconvenience and appreciate your interest. Please check back for updates later in the month.

Below the following map, you'll find instructions on interpreting and navigating this page. You can go here for a more detailed description of the Hubble academic research project and its goals. Below, you can look up Hubble's current view of the reachability of the address of your choice. Feel free to send suggestions and other feedback to hubble-support.

Black hole duration (hrs): < 8 < 16 < 24 24-48

Hubble uses PlanetLab vantage points to monitor prefixes around the world. This page lists those prefixes experiencing ongoing problems with all the following properties:

• All Hubble vantage points previously were able to reach the prefix.
• Some vantage points can still reach the prefix, whereas others fail to reach even the ISP owning the prefix.
• The problem persists through at least two consecutive 15-minute trials and at most 48 hours.

• For each black hole, the table gives the prefix, the origin AS (the ISP owning the prefix), the country, the percentage of Hubble vantage points able to reach the prefix in the last quarter-hourly set of probes, and the duration of the problem so far.
• The map adjoining the table shows the locations of those prefixes that we are able to geographically map using iPlane or MaxMind GeoLite City.
• Clicking a link in the table or a marker on the map brings up information on the black hole, including a link to a map showing which vantage points can and cannot reach the prefix.
• The darker the shadow below a marker, the more problem prefixes in that city. Zooming in on the map will allow you to choose between them.

• Distributed probing from PlanetLab sites.
• A synthesis of multiple information sources and techniques, including:
  • A hybrid passive/active monitoring approach (details in Section 3.3).
  • Historical data (details in Section 3.5.1).
  • A novel technique using spoofed probes to distinguish between a failure on a path to a destination and a failure on the path from the destination back to a source (details in Section 3.5.4 and Section 5.3).

• Persistent black holes affecting more than 10,000 prefixes.
• One in five of these black holes lasted more than 10 hours.
• 2/3 of them were cases of partial reachability, which cannot be explained by hardware failure alone.

In the future, we plan to expand this page to publish Hubble's real-time classifications of the problems and more of its raw data. This page includes GeoLite data created by MaxMind, available from http://www.maxmind.com/.

	Computer Science & Engineering University of Washington Box 352350 Seattle, WA  98195-2350 (206) 543-1695 voice, (206) 543-2969 FAX [comments to hubble-support]