Embedded Appliances for Precision Time Protocol Services
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23 July 2018

The rapid growth of the Internet of Things (IoT) makes network time synchronization a pressing issue. As more and more network-based devices come online, network-based timing becomes critical and with many emerging applications demanding far more accuracy, guaranteeing precise timing across LAN/MAN/WAN networks has become essential.

While Ethernet has become a pervasive and cost-effective means for data communications across local and wide-areas, it has not been optimal for applications requiring precise time synchronization. Specifically, Ethernet is nondeterministic, which creates challenges for real-time applications such as IoT-based real-time data acquisition and control applications, audio/video communications, defense related applications, and high-frequency trading which require precise time synchronization.

While time synchronization may be considered vital for Ethernet networks, network engineers may believe that all that is required is simply syncing their servers to a public internet clock. While perfectly suitable for consumer devices like smartphones, internet clocks are poorly suited for business networks for one key reason: security. To connect servers to an internet clock requires opening up port 123 on enterprise firewalls. 

IEEE 1588 Preciseion Time Protocol (PTP) surmounts the Ethernet latency and jitter issues throughhardware time-stamping at the Ethernet physical layer while keeping networks secure. The result is unprecedented accuracy in the 10-nanosecond to 100- nanosecond range that is achieved using an
Ethernet network to carry the timing packets, allowing for remarkable cost savings.

The Ethernet Timekeeping Challenge: Time Transfer Latency

A major challenge that must be surmounted for network-based timekeeping for Ethernet real-time applications is time transfer latency. The time transfer latency problem has two aspects: there is latency associated with processing of time packets by the operating system, as well as network latency created by the hubs, switches, cables, and other hardware that exist between clocks. It is in addressing operating system and network-based latencies where PTP is most successful.

PTP brings together time-stamping units with an innovative method for exchanging time-stamp detail between grandmaster (server) and slave (client) clocks. Slave clocks stay synchronized with grandmaster clocks by continuously exchanging timing packets with them — thereby compensating for the delays inherent within any Ethernet, packet-based network. A high level of accuracy is assured by using hardware time-stamping to mark each packet. Hardware time-stamping mitigates the normal delays that are incurred as packets traverse the operating systems, network and numerous routers and switches as they travel from their source to their destination. 

Ethernet-based Real-Time Data Acquisition/Control

Through enabling remarkable accuracy, PTP simplifies the deployment of IoT-based real-time data acquisition systems over Ethernet, each of which may have hundreds to thousands of independent sensors deployed using Ethernet networking. Each sensor can have an onboard 1588 slave clock that may be synchronized with the other sensors on the network to an accuracy of 1 microsecond. Every 5 milliseconds, each sensor may take a measurement and sends the information back to the controller, using the Ethernet LAN that is also used for time synchronization among the sensors. The result is that data is acquired synchronously from the entire system at precise intervals, without any trigger variation caused by propagation delay between the near and far sensors.

Grandmaster Servers: Foundation of PTP

PTP utilizes a client/server architecture to ensure precise timing and synchronization between PTP master servers — “grandmaster” clocks — and PTP clients that are distributed throughout the network. A grandmaster is the primary time source for its network domain and will typically get time from a GPS or cesium atomic clock, and grandmaster clocks are required to continue to provide timing synchronization services and maintain accurate time-stamping even in face of disruptions of connectivity with GPS satellites or other inputs.

There may be a single or multiple grandmaster clocks within the same network. PTP grandmasters can be deployed as standalone, dedicated embedded devices that can be integrated into an interface timing server shelf. Grandmasters are as important as their name implies. They are an essential component of any PTP solution because they are the primary reference source for all other PTP elements within their network domain.

Interface Masters Technologies: High-Performance, Low-Latency and CostEffective Precision Time Synchronization

Interface Masters Technologies is an innovator with an extensive portfolio of embedded appliances for Precision Time Protocol (PTP) deployments. Interface Masters’ Linux-based embedded networking appliance offerings equipped with PTP adapters can enable IT managers to seamlessly manage time
synchronization utilizing standard Linux management tools remotely at all worldwide locations. These solutions enable PTP grandmaster servers to be architected with simple, low-cost, low-power configurations providing PTP building blocks with support of range of computing and wireless/wired
networking features. Interface Masters’ appliances provide the flexibility, power, efficiency, and cost savings that are essential for success in today’s challenging PTP market, making them ideal for a range of applications requiring precision time synchronization.

Interface Masters Technologies has for over 20 years been providing off-the-shelf innovative network security solutions with customization services to OEMs, Fortune 100 and startup companies. Our headquarters are located in San Jose, California in the heart of Silicon Valley where we are proud to design and manufacture all of our products.  Based on MIPS, ARM, PowerPC and x86 processors, Interface Masters appliance models enable OEMs to significantly reduce time-to-market with reliable, pre-tested and pre-integrated networking solutions that can meet the most challenging security requirements. 

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