Dbeacon is a distributed multicast monitoring tool. The main purpose of a
beacon is to monitor other beacons' reachability and to collect statistics
such as loss, delay, and jitter between beacons. Dbeacon supports both
IPv4, and IPv6 multicast, and supports collecting information using both
Any Source Multicast (ASM) and Source-Specific Multicast (SSM).

WWW: http://fivebits.net/proj/dbeacon