问题：

[多选] Which of the following are shared distribution tree characteristics（）

A . Memory requirements are higher for shared distribution tree than for source distributiontree.
B . Creates a tree from a central RP to all last-hoprouters.
C . Uses a rendezvous point.
D . An optimal path is created between each source router and each last-hoprouter.
E . Place（S，G）entry in each router’smulticast routing table.
F . Place（*，G）entry in a router’smulticast routing to table.