Resolution: The default TTL for TIBCO Rendezvous multicast packets is always 16. Beginning with RV 8.4, there is a new parameter, "-udp-ttl", which allows users to set the number of hops for UDP packets.
-udp-ttl <hops>
UDP TTL
Available only with TRDP daemons. When present, the daemon sends UDP packets with a TTL value of hops (a positive integer, less than or equal to 256). When absent, the default TTL is 16 hops.