Agilent Measurement Journal - Issue 4 - 2008 - (Page 6)

Overview: The 1588 PTP Trying Early Device Implementations at the IEEE 1588 PlugFest A report on the 2007 International IEEE Symposium on Precision Clock Synchronization for Measurement, Control and Communication Martin Curran-Gray Research Engineer, Agilent Technologies martin_curran-gray@agilent.com The PTP is commonly known as just “1588,” which is the speciﬁcation number originally assigned by the IEEE during its development. Its tagline is “precision clock synchronization protocol for networked measurement and control systems,” a description that conveys its twofold purpose: to enable different pieces of equipment to collaborate and to create a means of providing control or measurement in the operation or characterization of a system. The protocol describes a set of messages and behaviors that allow devices with inherently different levels of precision to operate concurrently by orienting them — within the deﬁned accuracy and precision — to a common clock. In operation, the PTP provides a means for devices connected by some form of network (usually a LAN) to establish and distribute a shared notion of time. This allows creation of spatially dispersed or “distributed” systems that use a more decentralized operating paradigm than traditional, collocated, controller-centric test systems. While approaches such as Network Time Protocol (NTP) enable millisecond synchronization across a LAN, 1588 was created to achieve synchronization of a microsecond or better. INDUSTRY BRIEF H Held October 1-3, 2007, in Vienna, Austria, the 2007 International IEEE Symposium on Precision Clock Synchronization (ISPCS) for Measurement, Control and Communication was the year’s main conference event for the IEEE 1588 precision time protocol (PTP).1 The hosting organization was the Austrian Academy of Sciences Research Unit for Integrated Sensor Systems.2, 3 As at previous annual conferences, a “plugfest” was held to allow informal implementation testing of various devices running the protocol. During the three-day conference, the PlugFest occurred during the entire ﬁrst day and part of the second. Bugs were found and bugs were ﬁxed, but that’s what PlugFests are about. Engineers from a wide variety of companies, organizations, agencies and education institutions convene to try out early implementations of their devices in what is usually a friendly, intelligent and helpful environment. Infused with a spirit of mutual cooperation, seemingly everyone was eager to help one another ﬁnd and resolve problems — and thereby move the standard closer to commercial realization. Upconverter and eight-port splitter Downconverter GPS signal distribution (~100 m coax) Antenna on patio of roof pavilion Version 1 network Equipment running V1 Version 2 Ethernet network Equipment running V2 using direct-to-Ethernet mapping Version 2 IP network #1 Equipment running V2 using end-to-end transparent clocks Version 2 IP network #2 Equipment running V2 using peer-to-peer transparent clocks Version 2 IP network #3 Equipment running V2 using “telecom profile” Figure 1. A conceptual diagram of the PlugFest test network 6 Agilent Measurement Journal

Table of Contents Feed for the Digital Edition of Agilent Measurement Journal - Issue 4 - 2008

Agilent Measurement Journal - Issue 4 - 2008 Delivering Confidence through Compliance with Standards Contents Emerging Innovations Trying Early Device Implementations at the IEEE 1588 PlugFest Achieving Greater Confidence in Measurement Accuracy through Consistency in Calibration Services Overcoming the Challenges of RFID Component Testing 3GPP LTE: Introducing Single- Carrier FDMA Ensuring Reliable Operation and Performance in Converged IP Networks Testing Storage Area Networks and Devices at 8.5-Gb/s Fibre Channel Rates Choosing an Appropriate Calibration Method for Vector Network Analysis Making Traceable EVM Measurements with Digital Oscilloscopes Exploring Terahertz Measurement, Imaging and Spectroscopy: The Electromagnetic Spectrum’s Final Frontier Interpreting Quoted Specifications when Selecting Digitizers

Agilent Measurement Journal - Issue 4 - 2008

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