What are three circumstances under which a router sends link-state PDUs (LSPs)?
(Choose three)
A.
LSPs are sent periodically every 9 seconds
B.
LSPs are sent when there is a network change
C.
LSPs are sent during adjacency formation
D.
LSPs are sent in response to CSNP messages
E.
LSPs are sent in response to PSNP messages
Explanation:
Partial sequence number PDUs (PSNPs): A receiver multicasts these PDUs when it detects that it is missing a link-state PDU or when its link-state PDU database is out of date. The receiver sends a PSNP to the system that transmitted the CSNP, effectively requesting that the missing link-state PDU be transmitted. That router, in turn,
forwards the missing link-state PDU to the requesting router.