Hello. During last decade much attention was paid to topology discovery at inter-domain routing level. But most of these projects are only targeted on physical links discovery; at the same time there was little opportunity to check the real use of links by single AS. The knowledge of Autonomous System relationships from single AS view could be used in many cases. For example it could be used during designing AS or for traffic flow engineering purposes. In case to solve this problem we have invented several active probing algorithms for discovering real routing policy map from single AS view. One of them is based on using spoofed source IP. We send an echo request with record route option and source IP from our address space and as the result we can see the part of reverse trace from destination. This helps to understand which links are used by our AS. It is a kind of snapshot. This information is used in iteration process and the all data results in model of AS relationships which could be reversed to single view for every AS. At the current moment we cover with help of our nodes about 40% of transit AS, but with help of RIPE Atlas we will be able to cover more than 90%, and give back to community a tool for traffic flow prediction at interdomain routing level. Spoofing is obviously bad in most of cases, but not this time. We need opportunity to strictly spoof only one IP from our address space. The list technical requirements of our proposal: 1. 178.248.239.238 always will be used as spoofed address; 2. There will be about 15 experiments every day; 3. Each experiment will last not more than 10 minutes; 4. The total approximate packet generation activity from all nodes will be about 500 packets per second; 5. We need opportunity to have different measurement plans (list of destinations) on different nodes. We work with Planet Lab nodes in the same way: every day there is a new .gz archive with list of targets for all nodes, every node unpacks it and use then only a sublist of destinations, but the packet generation script is same on all nodes. We're open to discussion on procedures described above. Best regards, Alexader Asimov