results: characteristics of traffic by ASes map IP addresses to their origin Autonomous Systems consider distribution of bytes, packets, flows - by source and destination ASes top source ASes: Microsoft-AS-Block also: Shawfiber, JNIC-ASN, Abovenet, ACTTG, Telus top destination ASes: Hanaro (Korea), Chinalink (China), Dacomnet (Japan), Thrunet (Korea) Abovenet, AOL-Primehost, Chinanet-core-wan-north, Backbone-Guangdone-AP Hotmail-AS: 5th by flows, 17th by bytes