IEEE 1588 PTP

Solutions with IEEE 1588 PTP for Network Switches, Routers, and Infrastructures

IEEE 1588 PTP-based network switches, routers, and data centre infrastructures are critical for time synchronisation across connected devices. PTP devices and network devices play a key role in achieving precise timing and synchronisation using the PTP protocol.

PTP enables packet-based two-way synchronisation with sub-microsecond accuracy when hardware timestamping is used. In software-only implementations, the accuracy is typically limited to tens or even hundreds of microseconds due to operating system and processing delays.

We enable the IEEE 1588 PTP support in software and hardware for diverse telecommunication devices. By integrating PTP devices for precise timing, and with advanced timestamping capabilities, our custom solutions align the clocks of various network elements with extremely low latency.

Clock Types in IEEE 1588 PTP

IEEE 1588 Precision Time Protocol (PTP) networks rely on several specialised clock types to achieve precise time synchronisation across all connected devices. Understanding the roles of these clocks — Grandmaster, Ordinary, Boundary, and Transparent Clocks — is essential for designing robust network infrastructures that require accurate timing. Each clock type serves a distinct function within the PTP system, ensuring that time information is distributed efficiently and reliably throughout the entire network.

Grandmaster Clock

The Grandmaster Clock serves as the root timing reference in a precision time protocol (PTP) network. As the primary source of time synchronisation, the Grandmaster Clock is typically connected to a highly accurate external time source, such as a GPS receiver or an atomic clock, to guarantee exceptional clock accuracy.

Boundary Clock

A Boundary Clock is designed to enhance the scalability and reliability of time synchronisation in complex PTP networks. Unlike Ordinary Clocks, Boundary Clocks operate on two or more network interfaces, allowing them to connect and synchronise multiple network segments.

Ordinary Clock

An Ordinary Clock is the most common type of clock found in a PTP network. It operates on a single network interface and can function either as a master or a slave, determined by the specific parameters and overall configuration of the network.

Transparent Clock

A Transparent Clock is another important element in IEEE 1588 PTP networks. It measures the residence time that PTP messages spend inside a switch or router and then corrects the timing information in those packets before forwarding them.

How Does It Work?

IEEE 1588 functions by exchanging two-way timing messages between the master and slave clocks. The synchronisation process involves the exchange of PTP messages, including sync messages, announce messages, and follow up messages, between two clocks (master and slave) to synchronise clocks and achieve accurate clock synchronisation.

In PTP messages, the slave receives information about the time the master is on. Announce messages are used to establish which device becomes the Grandmaster. The delay is easily determined in this process.

Sync packets and PTP packets play a crucial role in the synchronization process by transmitting timing information. The protocol estimates the one-way message delay by halving the round-trip delay, under the assumption that forward and reverse path delays are symmetrical. In practice, any network asymmetry (e.g., queuing, different routing paths) can reduce accuracy, which is why hardware timestamping and network design considerations are critical in PTP deployments.

Benefits of IEEE 1588 Synchronisation Protocol

IEEE 1588 synchronisation protocol is essential for coordinating and aligning various components or processes within a system. It provides real-time applications with the following information:

Precise time-of-day (ToD) information
Time-stamped inputs
Scheduled and synchronised outputs

PTP is the only widely standardized protocol for sub-microsecond synchronization over packet networks. Its application areas include mobile networks, industrial process control, audio/video networks, smart energy distribution, transportation, automotive, and IIoT.

How Promwad Adopts This Technology

To implement the IEEE 1588v2 PTP functionality, we utilise Microchip SparX-5i Ethernet switches enhanced with Microchip 1588v2 PHYs and 10G PHYs.

The model range we employ:

Ethernet switches: VSC7546TSN, VSC7549TSN, VSC7552TSN, VSC7556TSN, VSC7558TSN
PHYs/10G PHYs: VSC8572, VSC8574

PTP configuration is managed according to IEEE 1588v2 and the relevant PTP profiles, ensuring compatibility and precise synchronisation. Proper domain selection is critical, as all PTP devices within a domain must operate consistently. Redundancy options are also configured to maintain reliability if the primary Grandmaster becomes unavailable.

PTP clocks, including master and slave roles, synchronise through standard PTP message exchanges (Sync, Follow_Up, Delay_Request, Delay_Response, and Announce). While software timestamps can be used, hardware timestamping on PHYs and switches is preferred to achieve sub-microsecond accuracy. Monitoring clock quality is essential, particularly during holdover or when integrating third-party Grandmasters.

Software Development with IStaX SDKs by Microchip

IEEE 1588v2 PTP is integrated as an application-level module within the IStaX SDKs. It operates on Microchip Ethernet switch hardware and is supported by a rewriter, egress port modules, and timing-aware PHYs.

IEEE 1588v2 is integrated as a module within the IStaX SDK, operating on Microchip SparX-5i Ethernet switches with hardware timestamping from timing-aware PHYs. Supported features include:

Ordinary and Boundary Clocks with end-to-end and peer-to-peer delay mechanisms
One-step and two-step Transparent Clocks
Local clock servo and BMCA (Best Master Clock Algorithm) for Grandmaster selection
Configurable sync intervals to balance message overhead and timing precision
IPv4 multicast/unicast transport, with support for multiple masters in unicast mode
Optional OCXO integration for slave holdover stability
Partial timing support (e.g. G.8275.2) for networks without full timing at every node

The design may incorporate an OCXO to provide IEEE 1588 slave functions and timing holdover capability. Partial timing support is available for profiles such as G.8275.2, enabling synchronisation over networks without full timing support at every node. The default PTP profile is used to set clock-port parameters for synchronisation unless a specific alternative profile is configured. Timing failover operation can be either revertive or non-revertive.

Additionally, we provide IT security audit services to assess network infrastructures comprehensively. This includes identifying potential vulnerabilities, implementing safety measures, and ensuring compliance with industry standards.

Supported Applications

Boundary Clock in IEEE 1588 Networks

PTP synchronisation profiles, introduced in IEEE 1588-2008, facilitate the adoption of PTP by various standards bodies (e.g. ITU-T, IETF, SMPTE, AES, IEC, Avnu, AUTOSAR, LXI, AIA) for specific applications such as financial/enterprise, professional broadcast, power industry, and test and measurement. Some profiles, such as G.8275.2, are designed to provide partial timing support, enabling accurate synchronization over networks without requiring full timing support from every node.

Our engineers enable support of the following profiles:

IEEE Std 1588-2019 for generic applications
G8275.1, G.8265.1 for telecom industry
IEEE Std 802.1AS for audio/video, industrial automation, and automotive applications

Our Tech Stack

Profiles

PTP blocks

Applications

5G/6G telecom systems | Multimedia broadcasting | Financial trading | Industrial automation

Configurable options

HW vendors and SW implementations

Our Case Studies in Telecom

Enterprise-Class Managed Switch Design

Telecom

Software Development, Hardware Design

Ethernet

Faster Processing & Transfer for NVMe Devices

Data Сentres, Telecom

Malware Analysis with Automatic File Scanning

Data Сentres, Network Security, Cybersecurity, Telecom

Software Development, Backend

Enterprise Data Storage System Development

Data Сentres, Telecom

Hardware Design

Antenna System for Improved Signal Reception

Telecom

FPGA Design

Wireless

Network Switch for Data Acquisition System

Industrial Automation, Telecom

Firmware Development, Hardware Design, Industrial Design, Manufacturing

Wireless

Low-cost ADC-MCU Integration for SDR Device

Telecom

Firmware Development, FPGA Design, Hardware Design

Mobile Application Design for Communications

Consumer Electronics, Telecom

Software Development, Android Mobile, Business Analysis, iOS, QA

Do you want to implement IEEE 1588 functionality for your project?

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FAQ

What are the key areas of implementation for PTP?

PTP is implemented in the hardware and software of Ethernet switches, routers, audio/video equipment, automotive systems, and various network management solutions.

How does IEEE 1588 PTP work?

The protocol determines the server and client operating modes, as well as the master and slave parts synchronisation messages. The slave synchronises with the master, which is the source of time. A master synchronised to a time reference, such as GPS or CDMA, is called a grandmaster.

The protocol includes:

Master sync messages
Master delay response messages
Slave delay request messages

The BMC technique enables several masters to agree upon the best clock for the network in addition to the messages.

At least one master and one slave are needed for synchronisation via LAN. A single master can synchronise with several slaves. The slaves use synchronisation messages from the masters to adjust their local ones. All of them record exact timestamps.