TimeKeeper Grandmasters

The TimeKeeper Grandmaster is the combination of the capabilities of TimeKeeper with a powerful hardware platform. In this section we’ll go over what this combination lets you do, and also go over the Grandmaster features.

GPS/GNSS input

TimeKeeper Grandmasters will operate as stratum servers, boundary clocks, in addition to distributing time from GPS. In some deployments, a GPS/GNSS antenna may not be an option, or installation may still be in progress when the appliance is deployed.

By default, the primary time source is the GPS/GNSS input. If the GPS/GNSS isn’t available, TimeKeeper will automatically fail over to any other defined sources so there’s nothing that needs to be done. However, if you’d like to make sure the GPS/GNSS isn’t used at all until the installation is complete, the GPS/GNSS source can be dragged to be the last source option (lowest priority) in the web GUI.

Note that the Grandmaster will retain a GPS/GNSS input, even if the GPS/GNSS source is deleted entirely. In that case, TimeKeeper will automatically define a GPS/GNSS source for you, but place it last in the list of sources.

GPS/GNSS connector

TimeKeeper Grandmaster Generation 2 uses a female SMA connection for the antenna input. This provides 5v to the antenna. The input to the device after amplifier and antenna gain as well as cabling/connector signal loss should be between 5 dB and 20 dB. Higher or lower than that can cause the system to not achieve GNSS lock. Cabling, antenna and connectors should all be 50 ohm.

PPS input/output

The default configuration for the PPS connector is as a PPS output. It can be optionally configured as an input instead. To configure this, connect the pulse-per-second signal to the SMA connection labeled “PPS” on the back of the Grandmaster. Then navigate to the Configuration and Management tab, select Add new source then click on PPS Input. Select a “Major Time” that should be used for wall-clock time then save and restart TimeKeeper.

PPS connector

TimeKeeper Grandmaster Generation 2 uses a female SMA 50 ohm connection for the PPS connector. The output is a 3.3v square wave with a duty cycle of 40%. When the configurable PPS input/output is configured for input a duty cycle of 20% or greater is recommended with a input pulse of 3.3v to 5v.

User management

The primary interface to the Grandmaster is via the web-based GUI. It is possible to access via ssh (once enabled), RS232 console, and keyboard/monitor. Some user accounts are disabled by default and must be explicitly enabled via the web GUI in order to be used.

These logins may be authenticated with RADIUS/TACACS+. See this for details.

VLAN and bonding support

VLAN interfaces and bonded interfaces are supported with TimeKeeper. Both are configured as normal for your distribution using the normal Linux tools. (VLAN configuration is also available on the TimeKeeper Grandmaster via the web GUI.)

Once the device is present, TimeKeeper can use it just like any other network device. A configuration that tracks PTP on VLAN 36 attached to eth0 would look like this:

SOURCE0() { 

Similarly, a bonded interface can be named also. If the underlying device(s) behind the VLAN or bond support hardware timestamping, TimeKeeper will automatically use it.

RAID support

High availability storage is provided on the Grandmaster out of the box. This storage is monitored by TimeKeeper and alerted on as needed. For details on managing the RAID devices, please refer here.

Factory reset

The factory settings for network configuration and time service settings can be restored with a “factory reset”. To perform the factory reset you must be able to log into the device via RS232 console (using 57600 baud, 8n1) or through a connected keyboard/monitor. Log in with the account “factoryreset” and the password “timekeeper”. Note: In earlier versions of TimeKeeper the password was “fsmlabs”. Once that is done you will be asked to confirm twice that you wish to perform a factory reset, and whether you’d like to shut down the unit when the step is complete. Once that is done the settings will be restored and the system will reboot or shutdown as requested. Once booted the system is back to factory original settings.

Command line configuration

Some Grandmaster capabilities, like networking options, can be configured from the command line. This allows users to connect to a system via the console remotely and easily configure the system so that it’s accessible via the rest of the network.

In general, once the network is configured, much of the remaining configuration is done via the web interface, either over http or https.

To use the command line interface, login as the “admin” user, (detailed in this section), via keyboard/monitor, RS232 console, or ssh. Once logged in, run timekeeper_cli from the shell and follow the prompts.

Some of the options offered by the command line interface involve editing files. In those cases, the environment variable EDITOR guides which editor will be used. Editor options include vi (the default) and nano, for example. To use the nano editor, run this command before executing timekeeper_cli:

export EDITOR=nano

Advanced routing options

The web interface can be used to set up most networking configurations on the Grandmaster, including interface addresses, the default gateway, DNS settings, VLANs, bonded interfaces, and more.

However, some networks require more complex routing capabilities. Policy based routing is one example of this. For users that do require more advanced capabilities, the TimeKeeper CLI mentioned above can be used to configure the device.

To configure these options, login as the admin user on the console or via SSH, and run timekeeper_cli. This will give you an option to configure advanced networking capabilities, including per-device routes and routing tables.


TimeKeeper operates using the NTP, Time and PTP protocols using the standard assigned ports in each case. Because the Grandmaster has multiple network interfaces, it may be necessary to adjust your network’s routing to allow and/or correctly route these packets.

The TimeKeeper Grandmaster allows access via the timekeeper_cli command described earlier to editing Linux’s standard “/etc/sysconfig/network-scripts/route-device” files where device is the name of the interface on which the route is being added.

For instance, if you had a system or network which needed to be accessed other than by the default route, you would enter the timekeeper_cli application, and apply changes by selecting:

[admin@gm ~]$ timekeeper_cli
	2. Configure advanced routing options
 > 2
	3. Configure per-device routes
 > 3

Then selecting the device which may require advanced routing configuration and editing its configuration there, using the standard format for Linux per-device routes, e.g.: via dev eth0

with the format ‘NETWORK/NETMASK “via” ROUTER “dev” DEVICE’. The above would enable broadcast UDP to be sent to the network via a router at on device eth0.

In uncommon scenarios, packets destined for an address may not have a route to a device. In those cases, like with broadcast PTP (, you may need to configure a route specfically for that device.

TimeKeeper will send multicast UDP packets on a configured interface for a given source or server regardless of routing policies.

If you’re routing multicast it may also be necessary to add routes to your multicast routers using the method above in addition to enabling Protocol Independent Multicast (PIM) or a variety of IGMP switch management features which are beyond the scope of this documentation. For information on IGMP snooping and routing multicast UDP, please consult your router and/or switch documentation. Alternatively, if multicast routing becomes complex, TimeKeeper client and server can instead use unicast PTP or NTP.

If you have questions on whether this option applies to you, please contact support@fsmlabs.com.