Development of new protocols or new architectures often require some evaluation in term of their impact on the current or future Internet. GHITLE is a graphical tool to generate hierarchical, Autonomous System (AS) level, topologies of the Internet.

A typical topology generated by GHITLE shows customer-provider and peer-peer relationships; a small, highly connected, dense core consisting of so-called "tier-1" providers; a large level of loosely connected stub networks; and one or more intermediate levels of ASES.

A topology is generated level by level, from the dense core to the customer level. An AS belonging to a level may have peer-peer relationships with other ASes from the same level or customer-provider relationships with ASes from an upper level in the hierarchy.

Several parameters are proposed to generate the topologies : the number of levels, the number of nodes per level, the number of providers and peers per AS, the preference shown by an AS when it connects to a provider.

GHITLE also provides tools to analyze the generated topology. It can draw the graph, plot degree statistics, degree distribution, and customer-provider or peer-peer statistics.

The statistics and descriptions of the graph can be saved in a human readable form. The image of the graph can be saved in postcript format.