A path to a new receiver is grafted onto the tree whereas an existing path in the tree is pruned once it is no longer used to reach receivers. A path to a new receiver is grafted onto the tree whereas an existing path in the tree is pruned once it is no longer used to reach receivers. The use of a core as a meeting place for sources and receivers facilitates creation of the multicast tree. Two of the most popular sparse mode protocols are described below. The tree is rooted at a core.
All sources send their data to the core and all receivers send explicit join messages to the core.
As the MBone has evolved, new protocols have been deployed. The eventual goal of multicast researchers is to make the MBone obsolete by making native multicast communication ubiquitous throughout the Internet. The use of a core as a meeting place for sources and receivers facilitates creation of the multicast tree. Two of the most popular sparse mode protocols are described below. The tree is rooted at a core.