The value of tmnxNtpMulticastAuthKeyId specifies the key-id of
the authentication key and its authentication type used by this
node when acting as an NTP server to receive and transmit NTP
packets to and from an NTP node. When an NTP packet is received
by this node the authentication key type, key id, and key must
be valid otherwise the packet will be rejected and an
tmnxNtpAuthMismatch notification generated. When the value of
tmnxNtpMulticastAuthKeyId has a value of '0', no authentication
is performed.