There are many limitations for the current IPv6 traceback technology advanced probabilistic packet marking scheme-v6 (APPM-v6). These limitations mainly include lack of marking space, fragmentation of marking information, easily to be recovered, a high price for path reconstruction and heavy load on routers. This thesis improved APPM-v6 and proposed improved probabilistic packet marking scheme-v6 (IPPM-v6). It redistributed marking area, which was divided into flag area and information area. Taking advantage of the "hop limit" field in IPv6 basic header, flag area can be used to tell the state of packets. Taking advantage of "routing extension header" field in IPv6 extension header, information area can be used to store the marking information. Besides, it made use of flag area to activate dynamic marking mechanism and differentiated unmarked packets and marked packets to prevent the information being covered, thus to reduce the rate of false positives. Theoretic analysis and experiment prove that IPPM-v6 is superior to APPM-v6 in the rate of false positives, convergence time, the weakest link, etc...
