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Internet Topology

Drawings of the AS-Graph


A coarse clustering of the whole AS-graph. The big orange disk represents all the ASes at most two hops away from AS 701 (UUnet).


The structure of the Internet Core inside the giant cluster. Each disk represents a cluster with edge density > 70%


The Dense Core: a 43-AS cluster with with edge density > 70%

Free Software

GDTANG: The Geographic Directed Tel Aviv University Network Generator. This is a Perl program that generates synthetic Internet-like topologies using an improved Barabasi-Albert type model. It produces networks with a a power-law degree distribution (of course). However, it also produces:

A much more realistic "Dense Core",

A pretty accurate number of leaves,

More realistic maximal degrees.

Geographically meaningfull clusters

It is also surprisingly fast (in comparison to BRITE or Inet).

Download ZIP • 6KB

See our papers below for more details.

The older, undirected and non-geographic generator (TANG) can be found here.

Download ZIP • 4KB


1.S. Bar, M. Gonen, and A. Wool. A geographic directed preferential Internet topology model.

Technical report, 2005. arXiv:cs.NI/0502061.

2. S. Bar, M. Gonen, and A. Wool. An incremental super-linear preferential Internet topology model. In 5th Annual Passive & Active Measurement Workshop (PAM), Antibes Juan-les-Pins, France, April 2004.

3. G. Sagie and A. Wool. A clustering approach for exploring the Internet structure. In Proc. 23rd IEEE Convention of Electrical & Electronics Engineers in Israel (IEEEI), pages 149-152, September 2004. Here is the full technical report (postscript).

4. Y. Shavitt, X. Sun, A. Wool, and B. Yener. Computing the unmeasured: An algebraic approach to Internet mapping. IEEE Journal on Selected Areas in Communications, 22(1):67-78, 2004.

A preliminary version of this work appeared in IEEE INFOCOM'2001.

Useful Links

1.Cidr-report: an up-to-date BGP data repository.

2. The graphviz page at AT&T, home of the neato and dot graph layout programs.

3. CAIDA, home of the Skitter project and other cool Internet visualization tools.

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