A.Session Close B.PPPSession Close C.Connect Close D.PPP Connection Close
A.ConnectClose B.A11-Registration-Request C.A9-Release-A8 D.A11-Registration-Reply
A.后者需要重新建立A8連接 B.后者不需要建立A10連接 C.后者需要建立A10連接 D.后者不需重新建立A8連接