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178

Options List

C.19

Option 34: NTP/PTP Server

C.19.1

General Description

Option 34 provides Network Time Protocol (NTP) and Precision Time Protocol (PTP)

servers in

Arbiter Models 1084A/B/C, 1088A/B and 1093A/B/C GPS series clocks. These instructions will
assist you in the setup and configuration of the Option 34 NTP/PTP server. Configure Option 34
using the Web Interface or the SSH Console.

Standard configuration includes two copper Ethernet ports. Optionally, order fiber optic con-

nectors. Standard fiber connector is type LC, 62.5/125 m 50/125 m multimode fiber. Contact
factory for other connector types.

Option 34 has two independent server ports that can access either the NTP (versions 1, 2, 3 or

4 frames) or the PTP servers. This option has been designed in accordance with the latest NTP
and PTP standards and may be updated whenever new firmware is available.

PTP with hardware assist offers much better accuracy than with NTP, however to achieve

these accuracies requires PTP-enabled network components that provide for latency and jitter to
be determined between the clock and each component. When designing for the ultimate in PTP
accuracy, evaluate every component in the complete network.

Network Time Protocol (NTP) Server

Option 34 allows the clock to act as network (NTP) time server over an Ethernet network and
understands NTP version 1 – 4 frames, while optionally supporting authentication via DES and
MD5 cryptographic checksums as defined in RFC 5905

. Option 34 supports symmetric key au-

thentication. Time is distributed over the network interface to computers, controllers and other
equipment needing the correct time. Option 34 allows a secure connection to configure, using either
the preferred HTTPS Web Interface, or using the SSH Console.

Precision Time Protocol (PTP) Server

Option 34 allows the clock to act as a Precision Time Server (PTP) according to Standard IEEE
1588 2008. However for highest accuracy, the entire network where PTP is required must have
PTP-enabled network components. Without hardware assist through the physical interface, PTP
will provide time with the same accuracy as with NTP. Accuracy with hardware assist using PTP
should be better than 1 microsecond. Accuracy without hardware assist should be better than 100
microseconds.

Configuration Protocols

Three types of configuration protocols are allowed on the Option 34: HTTP, HTTPS and Secure
Shell (SSH). Of the three, HTTPS and SSH permit secure channels on the network between the
user and the Option 34. If a secure channel is required, choose either HTTPS using the Web
Interface, or SSH using the Console. HTTPS requires that a valid signed certificate (PEM file) be
uploaded into the Option 34. Use of Console does not require a signed certificate. Both of these
methods are discussed in the following pages, and both require a Username and Password to open
a connection. To access Option 34 using the Web Interface you will need Web browser. To access

IEEE 1588v2 – IEEE 1588-2008

Includes RFC 5906, 5907 and 5908