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Managing NTP Servers for the CTPView Network (CTPView)

NTP servers are used to synchronize system clocks over an IP network. You can manage your NTP peers and clients from the NTP Server Settings window. This window displays the results of a query of the configured NTP peers. Table 1 describes the information provided in the results. From this window you can stop the NTP daemon, add and remove NTP peers, and synchronize to a particular peer. For more information about the information displayed in the summary, consult a reference on NTP.

Table 1: Summary Information for NTP Server Peers
Field Description

remote

Hostname or IP address of the reference clock source. LOCAL refers to the system time on the NTP server. Table 2 describes the meaning of a prefix to the name or address.

refid

Reference ID that identifies the type of the reference clock. Typically this is the primary clock to which that NTP server peer is synchronized. When the primary clock is unknown, 0.0.0.0 is displayed.

st

Stratum number of the NTP server peer.

t

Remote peer type: broadcast, local, multicast, or unicast.

when

Time since the last packet was received, in seconds. When this value matches the poll value, the reference clock is queried, and when is reset to zero.

poll

Polling interval, in seconds.

reach

Reachability register, displayed in octal format. Indicates whether data was readable from the NTP server peer at the last poll, and whether the peer was synchronized to another time source.

delay

Current estimated round-trip time for queries to the remote peer.

offset

Difference between the reference time value and the CTPView server clock.

jitter

Magnitude of the jitter between several time queries.

A prefix to the peer name or IP address indicates the fate of the peer in the clock selection process. Table 2 describes the possible values.

Table 2: Prefixes Designating Peer Clock Selection Status
Prefix Meaning

space

The peer is discarded as unreachable, synchronized to this server (I a synchronization loop), or having a very large synchronization distance.

x

Peer is discarded by the intersection algorithm as a false ticker.

-

Peer is discarded by the clustering algorithm as an outlier.

+

Peer is a survivor and a candidate for the combining algorithm.

#

Peer is a survivor, but is not one of the first six peers sorted by synchronization distance. If the association is ephemeral, it may be demobilized to conserve resources.

*

Peer has been declared the system peer and lends its variables to the system variables.

o

Peer has been declared the system peer and lends its variables to the system variables. However, the actual system synchronization is derived from a pulse-per-second (PPS) signal, either indirectly by means of the PPS reference clock drive or directly by means of the kernel interface.

A summary of NTP network client access lists the IP address and netmask for each network client. You can add and remove network clients and modify client netmasks.

Accessing the NTP Server Settings Window (CTPView)

To configure NTP servers:

  1. In the side pane, select Server > Administration.

    The Administrative Functions pane is displayed.

  2. Click NTP Server Configuration.

    The NTP Server Settings window is displayed.

Stopping the NTP Daemon (CTPView)

To stop the NTP sever daemon:

  • In the NTP Server Settings window, click Stop NTP Daemon.

    The connection to the listed NTP server peers is brought down, and the Summary of NTP Server Pairs table is cleared.

Adding an NTP Peer (CTPView)

To add an NTP peer to the summary table:

  1. In the NTP Server Settings window, type an IP address or fully qualified domain name in the Manage NTP Peers section.
  2. Click Add New NTP Peer.

    The peer address or name and information appear in the summary table.

Removing an NTP Peer (CTPView)

To remove an NTP peer from the list of configured peers:

  1. In the NTP Server Settings window, select a peer to remove in the Manage NTP Peers section.
  2. Click Remove Selected Peer.

    The peer is removed from the table, and the NTP daemon is restarted if it was running.

Synchronizing the CTPView Server to an NTP Peer (CTPView)

To manually synchronize the server to an NTP peer:

  1. In the NTP Server Settings window, select a peer for synchronization in the Manage NTP Peers section.
  2. Click Sync to Selected Peer.

Adding NTP Network Clients (CTPView)

To add a new network client:

  1. In the NTP Server Settings window, type an IP address or fully qualified domain name in the Manage NTP Client Access section.
  2. Click Add New Network Client.

    The client address or name and netmask appear in the summary table.

Removing an NTP Network Client (CTPView)

To remove an NTP network client from the list of configured clients:

  1. In the NTP Server Settings window, select a client to remove in the Manage NTP Client Access section.
  2. Click Remove Selected Network Client.

    The client is removed from the table, and the NTP daemon is restarted if it was running.

Modifying the Netmask of an NTP Network Client (CTPView)

To modify a client netmask:

  1. In the NTP Server Settings window, select a client in the Manage NTP Client Access section.
  2. Select a new netmask.
  3. Click Modify Client Netmask.

See Also