Multicast Scoping

Thu, 30 Aug 2018 | Routing TCP IP

You have seen in the preceding discussions of multicast routing issues that although multicast routing certainly uses fewer network resources than other strategies, such as replicated unicast or simple flooding, it can still be wasteful in some circumstances This is particularly true of broadcast-and-prune protocols when used in sparse topologies In some instances, a multicast source and all group members can be found close together in relation to the size of the entire internetwork In such a case, a mechanism that limits the multicast traffic to the general area on the internetwork in which the members are located would help conserve resources There also may be cases in which, for security or other policy reasons, the extent of the multicast traffic must be limited

When multicast traffic is confined to "islands," the traffic is scoped Put another way, multicast scoping is the practice of putting boundaries on the reach of multicast traffic