1. NTP Solutions Intro to the NTP solution set
5/9/2018
NTP Solutions Intro to the NTP solution set

2. What are Network Time Servers?
5/9/2018
What are Network Time Servers?
What are Network Time Servers used for?
Synchronizing computers and other clients over a network using Network Time Protocol (NTP)
In full NTP mode an NTP timeserver does not create traffic, it responds to time packet requests from clients
Our NTP servers use GPS or Time Codes as sources of synchronization
Ease of use plug & play = set & forget

3. What is NTP? NTP = Network Time Protocol
5/9/2018
What is NTP?
NTP = Network Time Protocol
It is an Internet Protocol developed by Professor David L. Mills of the University of Delaware during the 1980s
It requires a reference clock source
It uses UTC as its reference timescale
Uses an Intersection Algorithm
NTPv3 is still the official version of NTP
NTPv0 developed in 1985 in both Fuzzball and UNIX OS
NTPv1 released in 1988 as RFC 1059
NTPv2 released in – RFC 1119 published
In 1992, RFC 1305 defined NTPv3.
In 2010, RFC 5905 was published containing a proposed specification for NTPv4.
Harlan Stenn – now leads the open source project following retirement of David Mills.

4. How Does it Work? Hardware Server with Software Client
5/9/2018
How Does it Work?
Hardware Server with Software Client
Client selects “best” time source from list of servers
Client polls chosen servers at regular intervals to request time of day (TOD) packet
Client calculates round trip delay from receipt time of TOD packet
Client estimates UTC offset and updates its internal time base
Clock synchronization algorithm
A typical NTP client will regularly poll three or more servers on diverse networks. To synchronize its clock, the client must compute their time offset and round-trip delay. Time offset θ is defined by
θ = ( t 1 − t 0 ) + ( t 2 − t 3 ) 2 {\displaystyle \theta ={(t_{1}-t_{0})+(t_{2}-t_{3}) \over 2}} , and the round-trip delay δ by
δ = ( t 3 − t 0 ) − ( t 2 − t 1 ) {\displaystyle \delta ={(t_{3}-t_{0})-(t_{2}-t_{1})}} , where
t0 is the client's timestamp of the request packet transmission, t1 is the server's timestamp of the request packet reception, t2 is the server's timestamp of the response packet transmission and t3 is the client's timestamp of the response packet reception.[1]:19 The values for θ and δ are passed through filters and subjected to statistical analysis. Outliers are discarded and an estimate of time offset is derived from the best three remaining candidates. The clock frequency is then adjusted to reduce the offset gradually, creating a feedback loop.[1]:20
The synchronization is correct when both the incoming and outgoing routes between the client and the server have symmetrical nominal delay. If the routes do not have a common nominal delay, there will be a systematic bias of half the difference between the forward and backward travel times.[17]

5. How do the Clients select the Servers?
5/9/2018
How do the Clients select the Servers?
Time Servers are rated in Stratum levels:
Stratum 0 sources are Primary Reference clocks such as Cesium or GPS Clocks that cannot be connected directly to a network
Stratum 1 sources derive time directly from Stratum 0 sources (Such as GPS Disciplined Oscillators)
Stratum 2 sources derive time from Stratum 1 sources e.g. via a time code
Stratum 3 sources derive time from Stratum 2 sources etc. etc.
If a timeserver is unsynchronised it is rated as Stratum 16
Stratum 0
These are high-precision timekeeping devices such as atomic clocks, GPS or other radio clocks. They generate a very accurate pulse per second signal that triggers an interrupt and timestamp on a connected computer. Stratum 0 devices are also known as reference clocks.
Stratum 1
These are computers whose system time is synchronized to within a few microseconds of their attached stratum 0 devices. Stratum 1 servers may peer with other stratum 1 servers for sanity check and backup.[13] They are also referred to as primary time servers.[2][3]
Stratum 2 These are computers that are synchronized over a network to stratum 1 servers. Often a stratum 2 computer will query several stratum 1 servers. Stratum 2 computers may also peer with other stratum 2 computers to provide more stable and robust time for all devices in the peer group.
Stratum 3
These are computers that are synchronized to stratum 2 servers. They employ the same algorithms for peering and data sampling as stratum 2, and can themselves act as servers for stratum 4 computers, and so on. The upper limit for stratum is 15; stratum 16 is used to indicate that a device is unsynchronized. The NTP algorithms on each computer interact to construct a Bellman-Ford shortest-path spanning tree, to minimize the accumulated round-trip delay to the stratum 1 servers for all the clients.[1]:20

6. Other Timeserver Protocols
5/9/2018
Other Timeserver Protocols
SNTP – A simplified version of NTP that doesn’t include the delay compensation algorithm
Broadcast or Multicast NTP - clients passively listen to time updates after an initial round-trip calibrating exchange
Daytime & Time protocols – used for recording the time of events

7. What does NTPv4 do for you?
5/9/2018
What does NTPv4 do for you?
Use of floating-point arithmetic instead of fixed-point arithmetic.
Redesigned clock discipline algorithm that improves accuracy, handling of network jitter, and polling intervals.
Support for the nanokernel kernel implementation that provides nanosecond precision as well as improved algorithms.
Public-Key cryptography known as autokey that avoids having common secret keys.
Automatic server discovery (manycast mode)
Fast synchronization at startup and after network failures (burst mode)
New and revised drivers for reference clocks
Support for new platforms and operating systems

8. Accuracy and Capacity NTP is a nondeterministic time format
5/9/2018
Accuracy and Capacity
NTP is a nondeterministic time format
Dependent upon network symmetry and oscillator accuracy
Network traffic or traffic loading is also a factor
Internal oscillator – the more accurate the clock (Oscillator) in the client the longer it can go between updates and the greater the accuracy between those updates.
Typical Performance
Internet ~100ms
LAN ~1-5ms
Note that NTP is designed to produce very little network traffic, so almost any server can service thousands of clients. Server capacity is normally more about specmanship than actual need

9. 5/9/2018
Why use NTP?
Basic synchronization of all network compatible appliances on the network
Audit trails:-
logging time of events or actions
Legal time requirements – time stamping events that may later be relied upon in litigation
Time stamping of financial transactions or stock buying/selling
Time stamping of events or actions for safety purposes
NTP provides a low-cost solution to all of these applications

10. But NTP is Free from the Internet - why buy your own timeserver?
5/9/2018
But NTP is Free from the Internet - why buy your own timeserver?
Security.
Opening the NTP port on a company firewall adds to vulnerability
Management
Having your own server allows it to be managed
Traceability
Using the internet makes it harder to show traceability of a time source to UTC

11. 5/9/2018
NTP Server Overview
Almost every product that Brandywine make that has an Ethernet port includes the NTP server function
Some products are primarily designed as NTP Servers
Other products are focused on other functions, but NTP is included as a utility
Modular products can be configured with multiple NTP server ports and include and other functions

12. Stand – alone NTP Timeservers
5/9/2018
Stand – alone NTP Timeservers

13. NTV-100xG & IDC-100 Low cost, entry level products
5/9/2018
NTV-100xG & IDC-100
Low cost, entry level products
100 BaseT Ethernet NTPv3
NTV100 = GPS Ref - Rack Mount “RG”- Desktop “DG”
IDC-100 = IRIG B Ref
Web Page management
Simple crystal, oscillator

14. NTP80plus GPS Synchronized 3 independent Ethernet Ports
5/9/2018
NTP80plus
GPS Synchronized
Peer to Peer Capability
Long antenna cable length option available.
3 independent Ethernet Ports
100 BaseT Ethernet Interface
NTP V3/V4
Internal Oscillator choices – Rb, OCXO & TCXO (std)
1PPS on time output

15. ENTA-II GPS and IRIG B Synchronization (user configured)
5/9/2018
ENTA-II
GPS and IRIG B Synchronization (user configured)
Dual 100baseT Ethernet Ports
High stability OCXO as standard
Additional I/O (IRIG, Have Quick, 5x user programmable serial, analog clock driver)
UL listed

16. See “Brandywine Future Products” for details
5/9/2018
NTP800
Next Generation Utility NTP Timeserver
4 x Gb Ethernet Ports
GNSS Capability
Timecode Input
Dual Power Supplies – front loaded
1PPS, 10MHz, Timecode & Serial outputs
See “Brandywine Future Products” for details

17. Modular Systems with NTP
5/9/2018
Modular Systems with NTP

18. Modular Master Clock (MMC)
5/9/2018
Modular Master Clock (MMC)
2U or 1 U Versions (5 or 12 User Slots)
Redundant Power, Master Clock Modules available
Dual Port NTP OSM
Ethernet 100BaseT
NTPv3 (RFC-1305)
NTPv4 (RFC-5905)
Authentication: SHA-1, MD5
Hot-swappable modules

19. M210 and M211 Multiple Input Options Multiple Output Options
5/9/2018
M210 and M211
M210 Modular Timing System
Multiple Input Options
Multiple Output Options
3 Module Slots
Peer-to-Peer NTP capability
3 Port100BaseT Ethernet option
High level of intrinsic security
M211 Modular Timing System
9-slot version of M210
Talk about security aspects of M211 and M210 multi module applications.

20. See “Introducing the M212”
Cut-down version of MMC
No hot-swap capability
Shorter chassis depth
Commercial/Industrial specification
See “Introducing the M212”

21. Board Level NTP Timeserver

22. PCIe-5905 GNSS, IRIGB, Have Quick/1PPS standard OCXO standard
1Gb Ethernet port
Host setup via Web Page
NTPv4 timeserver

23. Other products with NTP capability

24. NFS-220/NFS-220plus GPS Synchronised HQ/1PPS Reference Inputs
OCXO & Rubidium oscillators
Multiple 1PPS & 10MHz Outputs
Multipurpose (Workhorse) Product
Single 10BaseT Ethernet port (NTPv3)
CE/AS/NZ Certified

25. FRU & TRU Satcom and other applications
Options for vibration isolated low noise OCXO
10x10 MHZ outputs with high isolation <100dB
2 independent 100BaseT Ethernet ports (NTPv3)
SAASM option

26. Precision Time System (PTS)
GPS or HQ/1PPS Synchronization
Rb oscillator
10MHZ, IRIG B, HQ,1PPS outputs
Single 100BaseT Ethernet port (NTPv3)
Dual redundant Capability
SAASM option

27. Portable Timing Unit (PTU)
GPS Synchronization
115VAC/Battery operated
Single 100BaseT Ethernet ports (NTPv3)
Portable

28. RTG-510
GPS Synchronized
20 programmable outputs for time code and pulse rates
Supports IRIG A, B, E, G, NASA36, HQ and 1PPS
Electrical and optical time code input and outputs
High stability OCXO
Dual independent 100BaseT NTP ports (NTPv3)
Redundant hot swappable power supplies

29. Product
NTP Ports
NTPv
Base-T
GNSS
Timecode Input
Oscillator
Peer-to-Peer
Authentication
Other Outputs
Other Features
Height
Dedicated NTP Timeservers
NTV-100RG 1 3
100
GPS No
Crystal
None
Desktop Option 1U
IDC-100
IRIG-B
NTP80plus
3/4
Yes
Option
TCXO/OCXO/Rb
1PPS
NTP800 4
1Gb
Multiple Inputs
TCXO/OCXO/Rb/CSAC
MD5, SHA-1
Multiple Outputs
ENTA-II 2
OCXO
Bus-level Solutions
PCIe-5905
1000
IRIG-B/HQ
Modular Platforms
M210
1-6
Any
Intrinsically secure
M211
1-24 3U
M212
2-26
SBAS
OCXO/Rb
MMC 3U
2-12 2U
MMC 1U
Other Products with NTP Capability
NFS-220/Plus 10
HQ/1PPS
TRU/FRU
PTS Rb
PTU
RTG-510

30. Summary
We have a range of NTP Timeservers to suit all applications and pockets
We provide unrivalled security features in certain platforms
NTP is seen as a utility across the product range
Watch out for specmanship from competitors