Illustrated TCP/IP by Matthew G. Naugle Wiley Computer Publishing, John Wiley & Sons, Inc. ISBN: 0471196568   Pub Date: 11/01/98

Chapter 265
Leaves, Branches, and the Root

A few terms should be explained before we continue. Those familiar with spanning trees already understand about leaves, branches, and the root. For those who are not, read on.

Refer to the slide. It shows the leaves, branches, and the root of a spanning tree. The leaves are simply the endpoints of the tree. If there are no other forwarding paths beyond a router path, then the interface is considered a leaf interface. If there are more forwarding paths to a host group, then the interface is considered a branch. The root is the source of the multicast transmission. There can be many sources for a multicast network.

Picture a tree. A tree has a root, a trunk, branches, and leaves. Leaves are the outermost part of the tree; in fact, they are endpoints. The branches contain the leaves, but leaves cannot contain branches. The root is the source of all life in the tree. Lose the root and the tree dies.

Leaves, Branches, and the Root