#Internet Time Servers, #GPS Time Server Appliances Internet Time Servers • Time from outside the network results in variability from the internet • Unknown time sources and unknown traceability • User unable to audit the time source GPS TIME SERVER APPLIANCES • Time from inside the network is at least 1,000 times more accurate • Direct connection to very accurate and traceable GPS time • Full logging of synchronization

1. Internet Time Servers
• Time from outside the network results in variability from the internet
• Unknown time sources and unknown traceability
• User unable to audit the time source
GPS Time Server Appliances
• Time from inside the network is at least 1,000 times more accurate
• Direct connection to very accurate and traceable GPS time
• Full logging of synchronization
Internet Time Servers,
GPS Time Server Appliances

3. The Traceability of Time Synchronization:
Inside vs Outside the Network
• Time from outside the
network results in variability
from the internet
• Unknown time sources and
unknown traceability
• User unable to audit
the time source
Internet
Time Servers
• Time from inside the
network is at least 1,000
times more accurate
• Direct connection to very
accurate and traceable GPS time
• Full logging of synchronization
GPS Time
Server Appliances
NTP-over-the-Internet Increases Synchronization
Variation
NTP is a mature network protocol for synchronizing a local
system to a time server. NTP time servers are widely available
on the internet. But you’ll need to carefully consider if inter-
net time servers are appropriate for your application. Even for
internet time servers operated by national authorities, such as
NIST or the US Naval Observatory that are based on extremely
accurate atomic clocks, there are many factors that impact trace-
ability. According to ntp.org, “If business, organization or human
life depends on having correct time or can be harmed by it being
wrong, you shouldn’t ‘just get it off the internet’.” [http://www.
pool.ntp.org/en/use.html, accessed Jan 15, 2016]
One problem with time synchronization is the variability of network
conditions. Network load, variable paths, and firewall settings can
impact time quality to the local system. To illustrate this effect we
can use the time quality monitoring feature of Spectracom’s
VelaSync™ time server. It has a built-in GPS receiver as its refer-
ence that is accurate to tens of nanoseconds. NTP can be used to
In today’s modern networking infrastructures, great care is taken
to ensure networks are reliable, highly available, and most of all,
secure. Cybersecurity has emerged as a critical area in all facets of
the internet. It’s an area that companies spend millions on each
year. Yet still, there are often overlooked areas which degrade
security. One example of this is time.
As simple as it sounds, time plays a critical role in synchronizing
core business and network systems. It supports authentication
protocols as well as accurate log files critical for an audit trail
necessary for any cyber forensics program. As such, synchroni-
zation is often a requirement for network security standards such
as the Payment Card Industry’s Data Security Standards. PCI DSS
section 10.4 requires a traceable time source for synchronization
of ecommerce systems.
This document briefly discusses the differences between a time
source from within the network compared to outside the
network with considerations for traceability for a network
deployment of network time protocol (NTP).

4. The Traceability of Time Synchronization: Inside vs Outside the Network
compare it to another GPS time server on a local area network.
The offset is around 15-20 microseconds (figure 1).
The VelaSync time server was then connected to some of the most
popular internet time servers. The variation result, shown in figure
2, is as high as tens of milliseconds — 1,000 times worse than NTP
across a local area network. If we assume all the time servers are
accurate then difference is solely due to greater path delay and
other dynamic conditions.
This variation is enough to question the traceability of time from
the internet.
The Internet Obscures Time Traceability
Perhaps more important, for a security-critical network, you need
to know the validity of the source used by the time server that dis-
tributes time to your network. Time from GPS signals is recognized
as the most accurate, available and traceable time source. GPS-
based time servers are easy and simple appliances to add to the
local network. Even when different GPS time servers are deployed
in different locations they will provide the same time regardless
of geographies. What’s more, GPS as a local time source can be
monitored so its logs can be part of the audit trail.
Internet time servers may utilize GPS (or similarly accurate time
sources) but you never know. To illustrate this point, we can use
another feature of the VelaSync time server software, known as
Time Map. The time map provides information available on the
source of the time servers. See figure 3.
Of the seven internet time servers monitored over a 24 hour period, 20
different time sources were identified. Less than half of the sources
could be identified as being directly from GPS. In one case, GPS time
was distributed through 3 different time servers. The best practice of
using NTP server pools is one reason why there are more sources than
time servers. Server pools rotate among various internet time servers,
each with their source of time, to reduce the chance of one bad or
unavailable time server catastrophically affecting the synchronization.
However, that is a problem for those requiring traceability. The source
of time is not known or predetermined.
Conclusion
Indeterminate source identification, indeterminate accuracy variation,
and the inability to log the resulting time synchronization calls to
question the use of time from the internet. What’s more, internet
time servers are subject to being spoofed (bad NTP data sent from
a faked IP address) and direct attacks including NTP poisoning,
replay, and denial of service. So don’t leave it to chance. When
there is a business-critical need to trace time to an accurate source,
the clear solution is GPS time server appliances deployed on the
local network.
HB TECHNOLOGIES with their partners offers several choices of high
performance time servers to meet a variety of requirements and
applications. Contact us to discuss which solution would be best for
solving your requirements.
Figure 1: The comparison between two GPS time servers on the same LAN using
NTP results in 15-20 microseconds offset.
Figure 2: The comparison of internet time servers as measured by NTP on a local
GPS time server. The scale is 1,000 times greater than figure 1.
Figure 3: A time map shows a graphical
diagram of NTP servers and their time
source. In one case, the time source was
distributed through 3 different servers
which can offset accuracy and obscures
traceability.

5. Accurate Time Essential for Video Surveillance Applications...
1 | Timing & Synchronization
As video surveillance hardware becomes IP-based, systems are able to take advantage of the network to improve efficiency and
performance. Time synchronization, in which all the clocks in cameras, recording equipment, and computers have the same time, is
simple to implement on the network. It utilizes a standard protocol and a network appliance known as a time server. What’s more,
the time server can be legally traceable to a time authority. The result is low-cost investment protection for the video system
deployment.
Introduction
Security professionals thrive in a “What if?” world. What if a security system deployment is not synchronized? An employee in a
major corporation clearly compromises corporate security, but the legal department declines to prosecute. Why? Because the
physical security system shows him entering the area several minutes after a particular event was logged on the computer network.
Time synchronization could have preempted this problem.
Assuming clocks in electronic devices are set correctly, they are inherently inaccurate because they drift. The risk of re-setting clocks
at infrequent intervals, in separate systems, with different times compounded by normal clock drift is unnecessary and is a legal
liability. A municipality came under public scrutiny and threat of lawsuit for inadequate response to a medical emergency. The time
stamp on video shows a man collapsing at one time, but the 9-1-1 call was made much later. It was determined subsequently that
the video recorder was manually set incorrectly.
A few years ago, 9-1-1 call centers were facing these types of lawsuits for allegedly not responding to emergencies in reasonable
amounts of time. Time-stamped records, especially those logged on voice recorders, are often subpoenaed in court cases. It is
imperative that these time records be legally traceable to a national standards authority. Synchronizing clocks to traceable time has
proven to be a successful defense of time stamped evidence.
Best practices for the use of video surveillance have been published by The Scientific Working Group for Imaging Technology
(SWGIT) as Recommendations and Guidelines for the Use of CCTV in Security Systems for Commercial Institutions. For security system
data to hold up in a court of law, one must demonstrate the ability to accurately re-create the events surrounding a particular
action. Accurate time stamping is essential for event reconstruction. The SWGIT recommendations specify the use of Network Time
Protocol (NTP) for IP-based systems and GPS-based timing equipment as an industry-standard time synchronization method.
Legal issues aside, synchronizing clocks greatly improves the efficiency of
operations for both the end user and the system integrator. Applications work
as expected, interoperability is ensured, and the costs of troubleshooting and
manually re-setting clocks are eliminated. Unsynchronized clocks lead to finger
pointing. Synchronized clocks offer peace-of-mind for every IP video
deployment.
Synchronization to Legally Traceable Time
Time, as measured by the second, is one of the seven legally-defined units of
measure. Since the Treaty of the Meter of 1875, time has been coordinated
worldwide. Today, official time, known as Coordinated Universal Time (UTC), is
measured by vibrations of the cesium atom, an extremely accurate time
constant. (UTC replaced Greenwich Mean Time [GMT] in 1972.) UTC is kept by
national metrology institutes like the National Institute of Standards and
Technology (NIST) in Boulder, Colorado. In order to synchronize clocks to
accurate time, traceability to NIST is required.
Implementing a NIST-traceable time synchronization system is made easy thanks to the Global Positioning System (GPS). GPS
provides a secure and cost-effective way to provide a traceable time synchronization source to a facility. The GPS system includes 24

6. 2 | Timing & Synchronization
satellites carrying onboard atomic clocks. The U.S. Naval Observatory monitors the satellites’ clocks and locks them to UTC for
accuracy and traceability to national and international standards. We are all familiar with the use of GPS to provide driving
directions. These systems use accurate time and the principle of triangulation to calculate the three-dimensional position anywhere
on earth. The same GPS signal can also be used to synchronize a local “master clock” that is used to distribute time to every clock in
the system.
Distribution of Network Time
Synchronization of security device clocks is a simple process for IP-based systems. Network Time Protocol (NTP) is an “open source”
time synchronization distribution standard sponsored by the Internet Engineering Task Force. Client software for NTP is widely
available for virtually any operating system and is typically preinstalled in IP-cameras, DVRs, computers, etc. Configuring an NTP
client is straightforward once the network has a master clock  also known as a time server.
Time servers are available for general use on the Internet.
The major benefit is they are free. Their primary liability is
their use requires and an open port in the firewall and free
sources of time cannot be guaranteed, nor traceable.
What’s more problematic, however, is they require
continuous internet connectivity so they can’t be used in
closed security systems. In any implementation, using a time
source “outside the network” is a liability and should be
considered only after thorough risk analysis.
A GPS time server provides an integrated solution that
enables accurate time stamps for video surveillance systems
as well as access control systems, time and attendance,
alarms, and other elements of the network infrastructure
(routers, firewalls, etc.). Legally traceable timestamps
provide necessary evidence and validation of events for
legal proceedings. For reliability and security, the time server synchronizes to the precision time code from GPS satellites. They
operate safely behind the firewall to synchronize all elements of network hardware and software (including system logs) down to
the millisecond over LANs or WANs, anywhere on the planet.
Improved Cyber Security
The convergence of security systems to the network does not distinguish between protecting physical assets and protecting data
assets. An integrated security program requires regular review and analysis of network activity. System logs and the log files created
by firewalls and intrusion detection systems are vital to the reduction of cyber security threats. If a network is not synchronized and
all the computer clocks keep a different time, it becomes almost impossible to detect and analyze malicious activity on the network.
Time synchronization allows analysts to determine accurately the effect of an intrusion so it can be dealt with efficiently.
Expanded Functionality. Network Security. Peace of Mind.
A GPS-based time server, such as the Spectracom NetClock® system, is a low cost and high reliability network element that offers
worry-free network time synchronization. It tracks up to twelve satellites simultaneously for precise synchronizing to atomic clocks
traceable to national and international standards. Installation and operation is simple; set-up and reporting are web-enabled. A
NetClock time server can be accessed, under appropriate security policies, anywhere within a network. Features include browser-
based remote diagnostics, configuration and control, and flash memory for remote software upgrades. Remote control and
monitoring can also be done through SNMP and Telnet.
Installing a GPS time server on your network establishes the essential hub for integrated security systems. In addition to the
Ethernet capability for IP networking, a NetClock time server features specialized time outputs for stand-alone devices like voice
recorders, display clocks, fire alarms, and much more.

7. 3 | Timing & Synchronization
Conclusion
In the world of security professionals, establishing time synchronization is becoming more crucial if efficiencies and economies of
scale of network convergence are to be realized, and as cyber threats to security continue to emerge. A GPS time server answers the
growing need for accuracy, reliability, and traceability in mission critical systems across IP networks.
References
1) Spectracom web site: http://www.spectracomcorp.com
2) The Scientific Working Group for Imaging Technology (SWGIT): http://www.theiai.org/guidelines/swgit/index.php
3) NTP Public Services Project: http://ntp.isc.org/bin/view/Main/WebHome
4) NIST Time and Frequency Division: http://tf.nist.gov/

8. Time Synchronization Solution
RS-485orNTP
Network #3
Server
Time & Attendance
Network #2
Hub/Switch
Domain
Controller
1PPS
NetClock
®
/NTP Time Server
RS-485
Ethernet Time Server
Gateway/Router
Hub/Switch
Workstations
DatabaseServer
Building Access Control
CCTVEvent Logging
Video Surveillance
DVR
Ethernet
Wireless Mesh Time Network
S P E C T R A C O M
S P E C T R A C O M
S P E C T R A C O M S P E C T R A C O M
12
1
2
3
4
5
6
7
8
9
10
11
S P E C T R A C O M
TimeView™
Displays
S P E C T R A C O M
IP Displays
Main Network
Wireless Transmitter
RS-485
Test
Equipment
GPS Satellites
GPS+GLONASS Antenna
GLONASS Satellites

9. Synchronized Communication Center
Workstations
Server
Voice/Dictation Recorder
IRIG
GPS Satellites
NetClock
®
/NTP Time Server
RS-485
Hub/Switch
Ethernet
S P E C T R A C O M
TimeView™
Displays
S P E C T R A C O M
IPSync™
Displays
Wireless Mesh Time Network
(For Multiple Display Clock Systems)
S P E C T R A C O M
S P E C T R A C O M
S P E C T R A C O M S P E C T R A C O M
Test
Equipment
10 MHZ
1 PPS
Fire Alarm
Event Relay
Workstations
Domain
Controller
Workstations
Domain
Controller
Radio
Network
VoIP 911 Telephony
Network
CAD
Network
Optional 3X Ethernet
(10/100/1000)
10/100 Ethernet
Legacy CAD/
Telephony
RS-232
Time & Attendance
Workstations
DatabaseServer
Building Access Control
CCTVEvent Logging
Video Surveillance
DVR
12
1
2
3
4
5
6
7
8
9
10
11
Agency Network - Main
Ethernet
Wireless Transmitter
GPS+GLONASS Antenna
GLONASS Satellites

10. The Legal EHR(Electronic Health Record)

11. HB TECHNOLOGIES: GPS: geolocalization, tracking system, Master Clock, Time synchronized,
QU'EST-CE QU'UN MASTER CLOCK? (HORLOGE MAITRE)
Les Horloges Maîtres prennent normalement un ou plusieurs signaux précis de référence de synchronisation en
entrée, puis convertir et distribuer ces références de temps à d'autres appareils pour que leurs horloges soient
presque aussi précises que l'horloge maître.
Les systèmes d'horloge Maîtres sont utilisés dans une grande variété d'applications et d'industries, notamment
l'aérospatiale et de la défense, la diffusion, la radio et les télécommunications, les systèmes de réseau, les
services financiers, les opérations d'urgence et de centres d'appels, et les soins de santé - essentiellement partout
la fiabilité des données et des signaux sont primordiaux.
Les horloges Maîtres du réseau distribuent leurs références de temps sur des réseaux locaux ou étendus. Il existe
également des solutions d'horloge de base et de haute précision qui utilisent des connexions en cuivre ou en fibre
optique pour la distribution de signaux numériques tels que IRIG, Havequick analogique précise, et timecodes
STANAG.
Les Horloges Maîtres peuvent également différer dans la source de leur référence temporelle. Il est un cas rare
pour une horloge maître soit en free-running et non synchronisé, ou au moins par rapport à une référence
externe en continu ou régulièrement. Ainsi, une caractéristique essentielle de tous les systèmes d'horloge maître
est qu'ils sont acceptés en précisant les références de synchronisation des signaux comme entrées. Le
SecureSync à système modulaire de synchronisation temps et fréquence peut accepter plus de 14 différents types
de signaux pour discipliner son horloge locale qui peut générer un nombre similaire de types de signaux pour
synchroniser d’autres appareils. En cas de perte de la référence externe (ou plus d'un pour la redondance),
l'horloge locale maintient la précision temporelle jusqu'à ce que la référence (s) soit restauré. Plusieurs options
d’horloge locale d'oscillateur sont offerts en fonction de la précision requise au cours de la période de "hold
over".
Utilisations courantes des Master clock
Les horloges maître offrent une signalisation précise et heure Légalement traçable à toutes les fonctions de
garde-temps dans un réseau.
Les horloges sont utilisées pour enregistrer les événements de secours pour améliorer les temps de réponse et de
régler les différends juridiques.
Les Systèmes de diffusion numériques comptent sur des horloges maître pour assurer la fiabilité des
transmissions sans fil en alignant la fréquence et le temps. La précision des plates-formes militaires C4ISR (radar,
satcom, simulation, guerre électronique) exige sur le calendrier précis. Les systèmes de télémesure et de test en
vol ne peuvent corréler capteur et d'autres données, si le temps est précisément synchronisé sur l'ensemble du
système. Les entreprises commerciales bénéficient opérations synchronisées de réseau pour les enregistrements
de précision, le dépannage, la sécurité, et pour permettre aux applications sensibles au temps aux niveaux
extrêmement élevés de précision.

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