AS-level Topology Collection Through Looking Glass Servers

Akmal Khan, Ted "Taekyoung" Kwon, Hyun-chul Kim, Yanghee Choi
ACM IMC 2013, Barcelona, Spain, Oct. 23-25, 2013.


While accurate and complete modeling of the Internet topology at the Autonomous System (AS) level is critical for future protocol design, performance evaluation, simulation and analysis, still it remains a challenge to construct its accurate representation. In this paper, we collect BGP route announcements of ASes from Looking glass (LG) servers. By querying LG servers, we build an AS topology estimate of around 116 K AS links, from which we discover 11 K new AS links and 686 new ASes. We conclude that collecting BGP traces from LG servers can help enhance the current view of the AS topology from the BGP collector projects (e.g., RouteViews).
[PDF (0.7MB)]

Measurement Methodology

We design a tool to automate querying Looking glass (LG) servers. Collecting data from an LG server is a multi-step process. First, for each LG server our tool learns, by parsing LG server websites, the supported LG commands and its LG routers to which our tool sends queries to collect the data. Second, to each LG router, our tool sends the show ip bgp summary command to the LG server. Third, from the returned response of show ip bgp summary, our tool extracts IP address(es) of the neighboring router(s) of the LG router. Fourth, by using the IP addresses of the neighboring routers, our tool sends a query of BGP neighbor ip advertised routes to collect the BGP routes advertised by the LG router to its neighboring routers. Finally, all the responses of the show ip bgp summary and BGP neighbor ip advertised routes commands from the LG server are stored in text files for constructing the AS topology.


LG lists
  • LG servers supporting BGP Summary command
  • LG servers supporting BGP Neighbors command

    AS Link Datasets
    We queried 245 LG servers that provide the option of running show ip bgp summary command from around 1.9 K locations (distributed across 110 countries), twice a week in the month of March 2013. We also queried 59 LG servers (out of the 245 ones) that provide the option of running BGP neighbor ip advertised routes command, once a week in the month of March 2013. Their LG routers are located in 250 locations distributed across 40 countries. To evaluate the unique contribution to AS topolgoy from our collected LG datasets, we have collected other AS topology datasets such as IRL, IRR, CAIDA Ark, and iPlane.
  • AS Links collected using BGP Neighbors Command
  • AS Links collected using BGP Summary Command
  • Interent Routing Registry(IRR)
  • CAIDA Ark
  • iPlane

  • Contact

    The scripts are not shared publicly to avoid excessive querying to LG servers. However, researchers can get these scripts by emailing to the following contact.