What is periodically multicasted (every 10 seconds) by the DIS on a LAN to ensure IS-IS Link
State Database accuracy?

A.
IIH

B.
LSP

C.
CSNP

D.
ISH

E.
PSNP

Explanation:
On broadcast networks, designated routers send complete sequence number PDU (CSNP)
packets to maintain database synchronization. The CSNP interval timer is the number of seconds
between transmissions of CNSP packets from this interface.