Time Sources are the fundamental dependency of the Timebeat application, and what we can do with those sources may be slightly different from what you are used to.
This is because Timebeat can be configured to use both the traditional BMCA (Best Master Clock Algorithm) steering method and our highly recommended MSSA (Multi-Source Synchronisation Algorithm) method.
To understand what model best suits your environment, contact one of our team here at TImebeat, and they can discuss everything you need to know. Alternatively, you might be interested in checking out our Squared guide for the best sync solution.
There are several reasons for using BMCA or MSSA. Typically, either model will work to the same effect, but utilising Timebeats' capabilities to operate as a Grandmaster or a Boundary clock allows for greater resiliency in your sync configuration and network.Â
In principle we always recommend having more than one source of UTC for each device, you can configure two separate instances of PTP sources using BMCA or MSSA without using multiple PTP domains, or similarly you can configure each source to have a different domain. If you are using multiple domains however and the Squared configuration please check out the guide as domains hold a specific purpose in Squared beyond just additional sources.
In short, 2 sources configured in the same domain, BMCA, will be used.
2 sources configured with different domains, MSSA, will be used.
Having multiple sources that are monitored and reported allows you to have a level of validation or traceability in your clock sync solution. This can be important for maintaining SLAs or complying with various regulations.
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When using MSSA Timebeat, it will utilise the median time source. This ensures your sync doesn't jump around but holds a consistent route forward, making for steady and stable sync.
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What this means in practice is that if you have three-time sources, it will synchronise to the source that is in the middle; an example:
Time source one is reading +4 microseconds, Â
Source 2 is reading -1 microseconds, and,
Source 3 is reading +2 microsecond
Timebeat would synchronise with source 3.
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This may appear to be counterproductive, as source 2 comes across as the most accurate to UTC reading -1 microseconds. However, it is our view that this is the source that disagrees the most with all other sources, therefore making it a "bad" source.
This system protects UTC's integrity, stability, and accuracy and provides triple redundancy.
Timebeat is flexible and can obtain UTC from a multitude of inputs, including PTP, NTP, PPS, and NMEA. If there is a source of UTC not present that you require, let us know, and we will see if we can make that happen for you.
For all Clock config information, check out our guides.