Dear All, C-BGP is an efficient and open-source simulation tool that allows to simulate the behavior of the intra- and interdomain routing protocols in large ISP networks. C-BGP is able to simulate networks with thousands of routers. A key feature ofco C-BGP compared to other simulators is that it is able to support the complex routing policies that are used by ISPs. Thanks to the support of France Telecom R&D, we have been able to use C-BGP to reproduce the behavior of BGP in a large Tier-1 ISP network. For this analysis, we have developped several tools to automatically convert the BGP configurations of Juniper (JUNOS) and Cisco (IOS) routers, the IGP topology and the BGP routes in the C-BGP format. With these tools, any network operator can easily build a C-BGP model of his/her network. With such a model, it is possible to perform different types of analysis on the ISP network, such as : - predicting the flow of the traffic through the network or determining the traffic matrix based on Netflow data (see article in January issue of ACM SIGCOMM Computer Communication Review) - predicting the impact of adding a new peering link on the BGP routes selected by the routers (see article in Nov/Dec issue of IEEE Network Magazine) - predicting the impact of link or router failures on the ISP network You can obtain C-BGP, the conversion tools and several papers describing the utilization of C-BGP to model an ISP network or compute traffic matrices from : http://cbgp.info.ucl.ac.be The website also contains several examples, such as a complete C-BGP model of the Abilene Network based on their publically available JUNOS configurations files. We believe that C-BGP could be very useful for ISPs willing to optimise the distribution and the selection of the BGP routes in their network. Comments, suggestions and questions from network operators are more than welcome. Best regards, Bruno Quoitin, Sebastien Tandel and Olivier Bonaventure -- CSE Dept. UCL, Belgium - http://www.info.ucl.ac.be/people/OBO/