Shared Trees

Shared Trees
There are two types of shared tree distribution:
 Unidirectional
 Bidirectional
Both of them work a little differently from source tree distribution. Shared tree architecture lies
in the possibility that there might be multiple sources for one multicast group. Instead of each individual
source creating its own SPT and distributing the data apart from the other sources, a shared
root is designated. Multiple sources for a multicast group forward their data to a shared root or
to a rendezvous point (RP). The rendezvous point then follows SPT to forward the data to the
members of the group. Figure 19.13 depicts how the shared tree distribution works.