Research on PIM-SM multicast routing improvement

PIM-SM multicast routing opposed to unicast technology has great advantages in multicast applications, but this routing technology has some flaws in the specific network topology. This article talks about the improvement for PIM-SM which is in the exceptional circumstances. For example, if SPT overlaps some or all of RPT, the DR of the source host will send the redundant data packets and the end-to-end delay among group members will be relatively large. Compared with before, the performance of improved PIM-SM doesn't reduce but also overcome these shortcomings.