Next: Core-Based Trees
Up: Multicast Routing
Rather than flooding the data everywhere, or flooding the membership
information everywhere, algorithms in the center-based trees category
map the multicast group address to a particular unicast address of a
router, and they build explicit distribution trees centered around
this particular router. There are three main problems that need to be
solved to get this approach to work:
Different protocols have come up with different solutions to these
problems. There are three center-based tree protocols worth us
exploring in a little detail because they illustrate different
approaches: Core-Based Trees (CBT), Sparse-mode PIM (SM-PIM) and the
Border Gateway Multicast Protocol (BGMP).
- How to perform the mapping from group address to center-address?
- How to choose the location of the center so that the distribution trees are efficient?
- How to actually construct the tree given the center address.