System Management
200
Basic System Configuration Guide
3HE 11010 AAAC TQZZA Edition: 01
• authentication keys — both DES and MD5 authentication are supported as well
as multiple keys, to provide increased security support in carrier and other
networks
• server addressing — servers may be defined using IPv4 or IPv6 addresses
• broadcast or multicast modes — when operating in these modes, the node will
receive or send using either a multicast (default 224.0.1.1) or a broadcast
address. Multicast is supported on the CSM Management port. Only IPv4
addressing is supported.
• alert when NTP server is not available — when none of the configured servers
are reachable on the node, the system reverts to manual timekeeping and
issues a critical alarm. When a server becomes available, a trap is issued
indicating that standard operation has resumed.
• NTP and SNTP — if both NTP and SNTP are enabled on the node, then SNTP
transitions to an operationally down state. If NTP is removed from the
configuration or shut down, then SNTP resumes an operationally up state.
• NTP priority — if a higher-priority time source such as GNSS or PTP is selected
on the node, then NTP transitions to an operationally down state. If the higher-
priority time source is disqualified or disabled, then NTP resumes an
operationally up state.
• gradual clock adjustment — as several applications (such as Service Assurance
Agent (SAA)) can use the clock, and if a major (128 ms or more) adjustment
must be performed, the adjustment is performed by programmatically stepping
the clock. If a minor (less than 128 ms) adjustment must be performed, then the
adjustment is performed by either speeding up or slowing down the clock.
• in order to facilitate proper operation once the standby CSM takes over from the
active CSM, it is required that the time on the secondary CSM be synchronized
with the clock of the active CSM
• in order to avoid the generation of too many events and traps, the NTP module
will rate limit the generation of events and traps to three per second. At that
point, a single trap will be generated that indicates that event/trap squashing is
taking place.
NTP accuracy depends on the accuracy of NTP packet timestamping. By default,
NTP packets are timestamped by the CSM where the NTP protocol is executed.
However, an enhanced NTP mode is available where the timestamping is performed
on the adapter card by the network processor. This reduces variations introduced by
packet delay within the router as well as by a busy CPU in the CSM. This enhanced
mode is only available for in-band NTP over a network interface. When the enhanced
NTP mode is used, NTP authentication is not supported.
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