A.LCP is used for basic PPP link setup and operation.
B.LCP is used for PPP CHAP authentication.
C.LCP is used for PPP over ATM （PPPoA） setup.
D.LCP is used for PPP over Ethernet （PPPoE） setup.
E.LCP is used for PPP over Frame Relay （PPPoFR） setup

A.The peer router sends an end-of RIB message to the restarting router
B.The peer router immediately removes the BGP routes that it learned from the restarting router from its BGP routing table
C.The restarting router does not remove any stale prefixes after the timer for stale entries expires
D.The router establishes BGP sessions with other routers and relearns the BGP routes from other routers that are also capable of graceful restart. The restarting router waits to receive updates from the neighboring routers. When the neighboring routers send end-of-RIB messages to indicate that they are done sending updates， the restarting router starts sending its own updates
E.The restarting router removes any stale prefixes after the timer for stale entries expires