In-Service Monitoring of PTP Performance
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Dominik Schneuwly discussed the value of in-service synchronization monitoring and probing, as well as the increasingly important role of network functions virtualization at ITSF 2016.
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In-Service Monitoring of PTP Performance
- 1. © 2016 ADVA Optical Networking. All rights reserved. Confidential.1 In-Service Monitoring of PTP Performance Dominik Schneuwly, 24th October 2016
- 2. © 2016 ADVA Optical Networking. All rights reserved. Confidential.2 Outline • Introduction • Sampling the Network Sites • Probing Techniques • Reduction of Data Quantity • Easy-to-Use Representation of Results • Conclusion and Outlook
- 3. © 2016 ADVA Optical Networking. All rights reserved. Confidential.3 What Are We Talking About? • Purpose: Monitor the performance of network in real time, raise an alarm when an action for preserving the performance is required • Means: • Permanent installation of sync probes in selected sites • Continous collection of measurement results • Anaysis and consolidation of the results into a form which is useful to the network operator (operations
- 4. © 2016 ADVA Optical Networking. All rights reserved. Confidential.4 Sync Probing Infrastructure NENENENENENE GM GNSS NE Probe GNSS Probe GNSS Probe GNSS eNode B Probe GNSS Data Base Analysis Presentation Data collection channel
- 5. © 2016 ADVA Optical Networking. All rights reserved. Confidential.5 Sync Probing Infrastructure • Probe: Tool located in the network for the acquisition of measured data • Challenge: Density of probes vs cost • Data collection channel: • Challenge: Limitation of used traffic data rate (bandwidth) • Data base: Storage of measured data • Challenge: Limitation of stored data quantity • Analysis: Processing of the measured data and automatic interpretation •
- 6. © 2016 ADVA Optical Networking. All rights reserved. Confidential.6 Sampling the Network Sites • Sampling: Choosing a reasonable number of probe installation sites • Two questions: • How many? Depends on gain/cost ratio - see upcoming slides • Where? Adopt a sampling strategy! • Sampling strategies: • Random • Worst case sites, i.e. cell sites • Impact-based: privilege sites where bad performance has strong impact • Witness path: take a representative path and probe on all sites along the path
- 7. © 2016 ADVA Optical Networking. All rights reserved. Confidential.7 Sampling Strategy: Cell Sites S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S GM GNSS Probe GNSS Probe GNSS Pro be GNSS Probe GNSS Probe GNSS Probe GNSS
- 8. © 2016 ADVA Optical Networking. All rights reserved. Confidential.8 Sampling Strategy: BC / APTSC Sites S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S S GM GNSS Probe GNSS Pro be GNSS Pro be GNSS Probe GNSS Probe GNSS
- 9. © 2016 ADVA Optical Networking. All rights reserved. Confidential.9 Sampling Strategy: Along a Path N max│TE│ eNode BNENENENENENENE Probe GNSS Probe GNSS Probe GNSS Probe GNSS 1.1 μs At different times of the day, i.e. with different traffic loads GM GNSS NE
- 10. © 2016 ADVA Optical Networking. All rights reserved. Confidential.10 Probing a Slave Clock – Physical Output 4 Slave’s physical output signal can be monitored vs. GNSS GNSS Slave Clock (DUT) T1 T4 T3 10 MHz/BITS/SyncE T1 T4 T3 1PPS T-GM Network CLK TIE and 1PPS Time Error CLK and 1PPS MTIE Sync Probe
- 11. © 2016 ADVA Optical Networking. All rights reserved. Confidential.11 T1 T4 Probing a Slave Clock – Passive Probing GNSS Slave Clock (DUT) T3 T1 T4 T3 T3 Packet MTIE Packet Time Error T-GM Network Sync Probe • The sync probe is placed at a calibrated distance from the slave clock • The sync probe functions as a passive PTP probe (fiber tapping or mirroring switch) • Probing is based on T3 embedded in the PTP delay request messages
- 12. © 2016 ADVA Optical Networking. All rights reserved. Confidential.12 Probing a Boundary Clock – Active Probing • The sync probe is placed at a calibrated distance from the master port of the boundary clock • The sync probe functions as slave clock and performs measurements at the same time (active PTP probe) • Probing is based on T1 & T4 embedded in the PTP sync messages Boundary Clock (DUT) Slave Clock T1 T4 T3 T1 T4 T3 T1 T4 Packet MTIE Time Error T3 T-GM GNSS Sync Probe
- 13. © 2016 ADVA Optical Networking. All rights reserved. Confidential.13 T1 T4 Probing a Boundary Clock – Passive Probing Boundary Clock (DUT) Slave Clock T3 T1 T4 T3 T1 Packet MTIE Packet Time Error T-GM GNSS Sync Probe • The sync probe is placed at a calibrated distance from the master port of the boundary clock • The sync probe functions as passive PTP probe (fiber tapping or mirroring switch) • Probing is based on T1 & T4 embedded in the PTP sync messages
- 14. © 2016 ADVA Optical Networking. All rights reserved. Confidential.14 Distribution of Data Processing • How much data processing in the probe? • How much data processing in the analyzer? • Has an impact on: • Total cost of N probes • Cost of analyzer • Quantity of data to be transfered (from probes to data base) and stored (in data base) Metric calculation InterpretationPre-processing 2way TE calculation TEFWD TEREV e.g.: peak-to-peak MTIE etc. e.g.: comparing with mask e.g.: packet selection
- 15. © 2016 ADVA Optical Networking. All rights reserved. Confidential.15 Distribution of Data Processing • System cost (CAPEX) vs cost of traffic bandwith (OPEX) • Typical optimization problem seen in network function virtualization (NFV) • General tendency in NFV: centralizing processing functions • Sync probing is getting more accessible All in Probe All in Analyzer Traffic bandwidth Equipment Cost CostofnProbes CostofAnalyzer
- 16. © 2016 ADVA Optical Networking. All rights reserved. Confidential.16 Presentation of the Results • An easy-to-use presentation is key! • Must help in deciding corrective actions • Examples:
- 17. © 2016 ADVA Optical Networking. All rights reserved. Confidential.17 What to Do With the Results Presentation of the results is action-oriented; two action fields: • Operations and maintenance: • Act upon configurable parameters, software, etc. • E.g., traffic engineering, QoS, load balancing, adapting packet rates, adapting flow networking, etc. • Repairs • Short term (minutes, hours) • OPEX related • Network expansion:
- 18. © 2016 ADVA Optical Networking. All rights reserved. Confidential.18 Conclusion and Outlook • In-service monitoring of sync complements the supply of sync • In-service monitoring of sync is as necessary as ever • Miniaturization and advanced data processing make sync probing more accessible • Network function virtualization (NFV) will play an increasingly important role
- 19. © 2016 ADVA Optical Networking. All rights reserved. Confidential.19 Thank You IMPORTANT NOTICE The content of this presentation is strictly confidential. ADVA Optical Networking is the exclusive owner or licensee of the content, material, and information in thispresentation. Any reproduction, publication or reprint, in whole or in part, is strictly prohibited. The information in this presentation may not be accurate, complete or up to date, and is provided without warranties or representations of any kind, either express orimplied. ADVA Optical Networking shall not be responsible for and disclaims any liability for any loss or damages, including without limitation, direct, indirect, incidental,consequential and special damages,alleged to have been caused by or in connection with using and/or relying on the information contained in this presentation. Copyright © for the entire content of this presentation: ADVA Optical Networking.