Model: MC-1-M (2U)
Doc. Ref. no. : - m05/om/101
Issue no. 14
Page 75 of 103
User’s Manual
MC-1-M NTP Clock output accuracy during holdover conditions (when device is Unlock as per ppm of
internal clock crystal) etc.
Since NTP client sends NTP request to NTP server at fixed intervals which can be from few seconds to
minutes, as during the interval, time of NTP client depends on its own local clock ppm. If there is too
much network load and congestion, there is possibility that NTP request as well as NTP responses to and
fro from NTP clients to NTP servers can be delayed by significant milliseconds at irregular intervals or
NTP packets may be discarded by network (as NTP packet is UDP based transmission packet) since it
may cross packet TTL (Time To Live) value in network.
11.3.4 NTP Hierarchical Time Distribution:
NTP architecture model consists of number of primary reference sources, synchronized by wire or radio
clock. There are other several multiple secondary time sources/clients which are arranged in hierarchal
manner in network which request time from primary reference sources. Under normal circumstances it is
intended that the synchronization subnet of primary and secondary servers assumes a hierarchical-
master-slave configuration with the primary servers at the root and secondary servers of decreasing
accuracy at successive levels toward the leaves.
NTP Server-client architecture are generally arranged in hierarchical arrangement in network. Refer
below figure 11.3 to understand time distribution model in hierarchical arrangement.
Figure 11.3: NTP Time distributions in Hierarchical Arrangement
As shown in figure 11.3, GPS Master Clock MC-1-M receives time form GPS Satellites. According to NTP
protocol, GPS satellites are considered to be operating at stratum level 0 as most accurate time source.
As the devices passes down to other levels of network architecture, stratum level increases by 1. GPS
