Chronos Sync MasterClass
Time & Timing in Packet Networks
The Chronos Synchronisation MasterClass is continuously evolving to keep up with changes in various industries and to ensure we deliver the latest information about time and timing in communication networks.
Networks are changing from traditional TDM technology to packet technology and the course material has been updated to include the latest developments in time, frequency & phase generation and transfer including updates from the Standards groups where new metrics are being proposed to address packet-based synchronisation techniques. Synchronisation requirements for next-generation fixed and wireless networks will be discussed.
The next Sync MasterClass session scheduled to take place at Chronos Technology is 19th & 20th June 2013
Chronos can also deliver the MasterClass in-house both in the UK and overseas. Please call +44 (0)1594 862200 for more information.
Building on the successful seminars and MasterClasses, Chronos presents a regular MasterClass on the specialist topic of Time & Timing for Telecommunications Networks. More than 1200 delegates from UK and overseas equipment manufacturers and network operators have attended the MasterClass since 1999.
The MasterClass course can be tailored to meet clients' specific needs, but will include the following essential elements:
- Pre-Course Question Session
- Introduction to Network Sync
- Fundamental Principles of Synchronisation
- Time Synchronisation (NTP and IEEE1588 PTP)
- Synchronisation Elements
- Synchronisation Quality Metrics & Testing
- Standards – ITU, IEEE & IETF
- Synchronisation over SDH & OTN
- Sync in Next Generation Networks, IP & Packet, emerging time & timing distribution technologies
- Core Network Sync & Exercises
- Mobile Network Sync
- Applications Affected by Sync
- Synchronisation over Leased Lines
- Architecture & Planning
- Post Course Questions
Syllabus - Day 1
Detailed Sync MasterClass Syllabus
Pre-Course Question Session
The day kicks of with a quiz covering basic telecommunications terminology and synchronisation. This course is marked before the start of day 2 and feedback given to the delegates. The quiz is used to measure the improvement in the delegate’s knowledge over the course as the test is repeated on Day 2.
- Written test to assess level of knowledge
- Over 40 questions and acronym definitions
Introduction to Network Synchronisation
As an introduction this session looks at how networks have evolved and how the increase in the number of network operators and the migration to fully digital networks has increased the need for Synchronisation. Problems that result when Synchronisation Networks fail to deliver adequate Synchronisation quality are introduced. Real world issues with Synchronisation networks are introduced.
- History of Telecoms Synchronisation
- Emerging new technologies
- Basic misconceptions about sync
- Typical sync routes through a network
- Impact of poor sync on carriers’ services
- Impact of poor Sync on Mobile Networks
Fundamental Principles of Synchronisation
This section covers the fundamental principles of Network Synchronisation starting with the classical architecture of Synchronisation Networks. Primary Reference Clocks (PRC) and Slave Clocks are explained and the concept of an ideal clock and a noisy clock are introduced. Slips and Pointer Movements, the symptoms of poor synchronisation in synchronous switched networks and SDH, are discussed. How synchronisation can be transported across networks is explained and issues that can arise with mixed transmission technologies are raised.
- Acronyms and Definitions
- Classical Network Synchronisation Architecture
- Clock Noise and noise characterisation
- Jitter and Wander
- Slips and Pointer Adjustments
- Introduction to mixed technology problems
Time Synchronisation (NTP & PTP IEEE1588)
Networks need good frequency synchronisation to function correctly. With the rise of networked computing there is additionally an increasing need for common Time of Day clocks between elements in computer and telecommunications Networks. This section explains Universal Coordinated Time (UTC) and how it is disseminated; concentrating primarily on Network Timing Protocol as the main way of distributing timing to computers using over IP networks. Other techniques are mentioned and Precision Timing Protocol- IEEE1588 is introduced. IEEE1588 is being investigated for use in Telecom networks because of its increased accuracy. References will be provided for further in-depth study.
- History of Computer Time
- Universal Coordinated Time (UTC)
- NTP Applications
- Overview of Design & Operation
- “Carrier-Class" and hardware assisted NTP
- Introduction to IEEE1588 - PTP
This section starts with a look at the history of Timekeeping from Early Sundials right through to Atomic Clocks. It looks at the types of oscillator used in Telecommunications Networks today for Primary Reference Clock, Synchronisation Supply Units and SDH Equipment Clocks. Examples of PRC and SSU products produced by the major Synchronisation equipment manufactures Symmetricom and Oscilloquartz are shown.
- Types of Oscillator
- Introduction to GPS
- PRS Clocks
- Slave Clocks—SSU and SEC
- Comparison of Regional standards
- VCO and PLL Principles
- Examples of SSU and PRC Products
- Other off-air references – GLONASS, Galileo, Compass, eLORAN
- GPS based PRCs – including practical considerations
Synchronisation Quality Metrics and Testing
We have looked at how good synchronisation can be generated and distributed; now we look at ways to measure equipment and networks and confirm they are performing to specification. The definitions for Time Interval Error and how this is used to derive the two key telecommunications quality metrics MTIE and TDEV is presented. An example of the use of MTIE and TDEV to evaluate the performance of GPS receivers to see if they meet the ITU requirements for a Primary reference clock is discussed. This section will include exercises to aid with the understanding of MTIE and TDEV. Also discussed are the types of test equipment that can be used to test synchronisation quality. If lab available overnight Sync Test to be run for group analysis at start of Day 2. Synchronisation analysis tools will be demonstrated.
- Derivation of TIE and sample data
- Derivation of MTIE and sample data
- Derivation of TDEV and sample data
- Real application examples
- Sync test Equipment & Solutions
The relationship between the key standards organisations is shown and a list of the key standards for Synchronisation Networks is given. A comparison the performance requirements of ETSI and ITU SSU clocks are given.
- ITU-T, ETSI, ANSI and Telcordia Standards
- Evolution to NGN timing protocols – IEEE & IETF standards
- Clock standards
- Electrical interface standards
- Jitter and Wander standards
- Comparison of Regional standards
Syllabus - Day 2
Synchronisation over SDH & WDM
SDH networks are the key means of transporting synchronisation between locations in telecommunications networks. Properly Synchronised SDH networks allow the transport of Synchronisation; poorly synchronised SDH networks can seriously damage network performance. This section looks at how SDH networks are synchronised, how they carry services and how they can introduce synchronisation impairments onto the services they carry due to the pointer mechanism.
The implications of WDM networks on synchronisation is introduced and although WDM should be a transparent from a synchronisation perspective the increased distances and flexibility can cause issues that need to be considered. The synchronisation aspects of Optical Transport Networks (OTN) – the standardised ITU specification for transport over WDM is introduced at a high level.
- Review of SDH technology
- Network Elements
- Sync Status Messages
- Sample SDH network MTIE “signatures”
- Use of Retimers
- Sync of WDM
- High level Review of Sync in Optical Transport Networks (OTN)
- Optical Network Signal Structure
- OTN Sync Transport Mechanisms
- Examination of the transport of SDH clients over the OTN
Synchronisation in Next Generation Networks
As traditional TDM and Data/Packet networks converge, methods for distributing time and timing when the traditional sync distribution medium is broken are assessed. After a brief revision of ATM the key ways of getting synchronisation of services carried over packet networks are analysed: Network Synchronous, Adaptive Clock Recovery and Differential (Synchronous Residual Time Stamp). Effects of packet delay variation are discussed along with mechanisms of regenerating good synchronisation at the edge of the packet network, including NTP, PTP (IEEE1588) and Carrier Class NTP. Emerging standards and technology are compared, including G.8261 (formerly G.pactiming), G.paclock & G.pacmod. Synchronous Ethernet and G.UTI (DTI/TTI)
- Review of packet network technology
- Network elements
- Transport mechanism
- Network Synchronous, Adaptive Clock Recovery and SRTS (Differential) Methods.
- Sample ATM, and ACR network element MTIE "signatures”
- Sync over Packet Networks – PTP, NTP and “Carrier Class” NTP
- G.8261 and the evolution to Next Generation Network standards including G.paclock and G.pacmod
- Synchronous Ethernet
Core Network Sync & Exercises
This section looks at the planning rules for SDH and briefly OTN networks and looks at the maximum distribution chains that are permitted by the standards. A planning exercise for a number of SDH Sub-networks is included allowing delegates to put into practice some of the concepts learnt in this and the SDH section of the course.
- Sync Distribution techniques
- Transport Mechanism
- Sync Design Exercises
Mobile Network Sync
Mobile networks are key customer for many bandwidth suppliers and it is a key service with stringent Synchronisation requirements. The synchronisation requirements of mobile networks are discussed. This section will include an overview of the synchronisation implications of implementing Location based services.
- Mobile Network Requirements
- GSM and 3G
- Network and Base Station Sync
- Mobile Network Architecture and Connectivity
- Sync. for location based services
- WiMAX sync requirements
Synchronisation Delivery over Leased lines
Sync Delivery over leased lines is fundamental to many mobile network operators Network designs. This section looks at the delivery mechanisms used by mobile operators and their performance. PDH is still a key transport mechanism these networks; mostly now it is relegated to the access network where it still finds widespread application for example in the transport of n x 2Mbit/s services down to mobile base stations. DSL is becoming increasingly important to enable higher bandwidth access and can provide cost effective leased line service delivery. The different DSL technologies are reviewed and their ability to transport good Synchronisation discussed. Measurement results for SDH, PDH and DSL networks are presented and recommendations on performance testing made.
- PDH issues
- SDH Issues
- ATM Issues
- Packet Access
- HDSL and SHDSL issues
- Measured results
Applications affected by Sync
Ubiquitous packet based networks are being proposed by many operators. As IP traffic dominates it makes sense to move all services to run over a common packet based platform. However many legacy services have synchronisation requirements which need to be considered before the existing PSTN network can be scrapped without affecting existing customer services. Implications of VoIP networks are discussed in detail and the issues of carrying Fax and Modem traffic over these networks are analysed.
- Voice Over IP
- Impairments to VoIP cased by poor sync
- Fax and MODEM over IP
Architecture & Planning
A good synchronisation network needs a good architecture and good planning. This section looks at Sync Network Architecture options: Master Slave, Hybrid and Flat. It then looks at the issues of planning at the PRC, SSU and SEC levels
- Inter-Network Architecture
- Intra-Network Architecture
- Master Slave PRC
- Flat PRC
- Hybrid PRC
- Intra-Node Architecture
- Sync Element Interworking
- Planning Rules
- PRC Level
- SSU Level
- PRC Autonomy Period
- SEC Level
- Network Examples
Post Course Questions
During the breaks in the second day a paper based quiz is completed, this is marked interactively at the close of the course.
- Repeat of questions from day 1
- Comparison of marks
- Review of answers
The course has been formulated for manufacturers of communications equipment, licensed carriers and users of digital wireline and wireless traffic. The course is suitable for:
- Sales and Bid Preparation staff
- Network Planners and Architects
- Engineers and Technicians
- Operations and Maintenance staff
- Customer Liaison Staff
- Network Management Staff
- Senior Line Management of staff involved with sync issues
The Course Cost - includes:
Coffee, Lunch, Tea on days one and two
Dinner day one
Folder with course notes
Delegates generally stay at The Chase Hotel, Ross-on-Wye. Accommodation is not included in the cost of the course, however Chronos corporate rate applies.
For UK based courses, there are a number of alternative hotels in the Ross-on-Wye area. Click on this link to view them.