Synchronization protection & redundancy in ng networks itsf 2015
0 likes128 views
The document discusses synchronization protection and redundancy in next-generation networks, outlining potential failures such as GNSS outages and equipment failures, as well as strategies for protection, including switching to secondary sources and using multiple grandmasters. It compares different oscillator types, highlighting advantages of high-quality oscillators over rubidium, particularly in terms of temperature stability and cost-effectiveness. The document concludes that combining high-temperature stability with GNSS references can optimize performance and costs.
![© 2015 ADVA Optical Networking. All rights reserved. Confidential.14
Environmental Condition
• Synchronization devices at the access network are subject to
wider temperature variation!
• ETSI Environmental Classes:
Class
#
Class description Temp.
change rate
Temp.
change range
Delta
3.6 Control room locations 0.5°C / min [+25, +30°C] 5°C
3.1 Temp. controlled locations 0.5°C / min [+25, +40°C] 15
3.2 Partly temp. controlled locations 0.5°C / min [+25, +55°C] 30
3.3 Not temp. controlled locations 0.5°C / min [-5, +45°C] 50
4.1 Non-weatherprotected locations 0.5°C / min [-10, +40°C] 50
3.5 Sheltered locations 1°C / min [-40, +40°C] 80
Core
Access
Ethernet Access NE - typical
operational temperature range
[-40, +65°C]
Higher temperatures are expected in other continents](https://image.slidesharecdn.com/synchronizationprotectionredundancyinngnetworks-itsf2015-151124165133-lva1-app6892/85/Synchronization-protection-amp-redundancy-in-ng-networks-itsf-2015-14-320.jpg)
![© 2015 ADVA Optical Networking. All rights reserved. Confidential.18
HQQ Vs Rb – Controlled Room (25-30C)
• Tested in the Oven with controlled room profile
• Phase Holdover over 48 hours below 200nsec !
Enter
Holdover
After locked
to GPS for 2
days 2 days HQQ
holdover
below 200
nsec !
Temperature effects are
seen in the Rb TIE
0 2 4 6 8 10 12 14 16 x104
Time [sec]
0 2 4 6 8 10 12 14 16 x104
Time [sec]
-50
50
0
100
150
200
TIE[nsec]Temperature[C]
25
26
27
28
29
30](https://image.slidesharecdn.com/synchronizationprotectionredundancyinngnetworks-itsf2015-151124165133-lva1-app6892/85/Synchronization-protection-amp-redundancy-in-ng-networks-itsf-2015-18-320.jpg)
![© 2015 ADVA Optical Networking. All rights reserved. Confidential.19
120
HQQ Vs Rb – Temp’ Controlled Room (25-40C)
Temperature effects are
seen in the Rb FFO
Temperature
effects are
NOT seen in the
HQQ FFO
Temperature[C]
25
30
35
40
0 20 40
Time [Hours]
60 80 100 120
0 20 40
Time [Hours]
100
x10−10
FFO
-0.5
0
0.5
1
1.5
2
2.5
3
12060 80](https://image.slidesharecdn.com/synchronizationprotectionredundancyinngnetworks-itsf2015-151124165133-lva1-app6892/85/Synchronization-protection-amp-redundancy-in-ng-networks-itsf-2015-19-320.jpg)
![© 2015 ADVA Optical Networking. All rights reserved. Confidential.20
HQQ Vs Rb – Temp’ Controlled Room (25-40C)
Temperature effects are
seen in the Rb TIE
Enter Holdover
After locked to GPS
for 2 days 2 days HQQ
holdover
below
1800nsec !
2 days Rb
holdover are
above 13500
nsec !
0 20 40
Time [Hours]
60 80 100 120x104
TIE[nsec]
-2000
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
Temperature[C]
25
30
35
40
0 20 40
Time [Hours]
60 80 100 120
Temperature effects are NOT seen in the HQQ TIE](https://image.slidesharecdn.com/synchronizationprotectionredundancyinngnetworks-itsf2015-151124165133-lva1-app6892/85/Synchronization-protection-amp-redundancy-in-ng-networks-itsf-2015-20-320.jpg)
Synchronization protection & redundancy in ng networks itsf 2015
- 1. Synchronization Protection & Redundancy in NG Networks Nov 2015 Nir Laufer , Director Product Line Management ITSF 2015
- 2. © 2015 ADVA Optical Networking. All rights reserved. Confidential.2 What can possibly go wrong … ? • GNSS failure • Jamming • Antenna breakdown (lightning , cable cut) • Equipment failure • HW failure • Connectivity to GM is lost • Network outage or extreme overload
- 3. © 2015 ADVA Optical Networking. All rights reserved. Confidential.3 Protection and Redundancy Options: • Protection at Slave/BC side – switching to a standby GM based on the relevant Best Master Clock Algorithm (BMCA) • May results network rearrangement • Switching between GM’s may results phase transient • Protection at Master side – GM switching to secondary source in case the primary source fails • Might prevent network rearrangement if secondary source if sufficiently good Both options can be combined in order to achieve best protection & redundancy
- 4. © 2015 ADVA Optical Networking. All rights reserved. Confidential.4 Protection G.8265.1 – Multiple Masters T-GM #2 GNSS PTP Grandmaster Packet-Based Backhaul Network T-SC First Aggregation Node T-GM #1 GNSS PTP Grandmaster • Frequency Delivery • IP Unicast – End to End
- 5. © 2015 ADVA Optical Networking. All rights reserved. Confidential.5 Protection G.8275.1 – Multiple Masters Packet-Based Backhaul Network T-GM GNSS PRTC PTP Grandmaster & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E Ethernet Multicast T-GM PTP Grandmaster & Sync-E • Phase & Frequency Delivery • Eth’ Multicast – Hop to Hop
- 6. © 2015 ADVA Optical Networking. All rights reserved. Confidential.6 Distributed Architecture Using Mini-GM T-GM GNSS PTP Grandmaster Packet-Based Backhaul Network GNSS T-SC T-SC T-SC First Aggregation Node Mini-GM
- 7. © 2015 ADVA Optical Networking. All rights reserved. Confidential.7 Distributed GM Protection Options • What if GNSS is locally in outage (e.g. Jamming) 1. Physical layer input • Sync-E • BITS • Can be a good option – but not always available 2. PTP input (APTS) • Recovering both frequency and phase • Recovering only frequency which is used for phase holdover • Will be reviewed in details in Dominik presentation 3. Holdover based on local oscillator • Always available
- 8. © 2015 ADVA Optical Networking. All rights reserved. Confidential.8 Short Term Holdover ±100ns ±200ns ±250ns ±250ns ±150ns ±550ns PRTC T-GM Random Network Variation Node Asymmetry (±50ns per node) Link Asymmetry Compensation Short-Term Holdover End Application ±1.1µs Network Equipment Budget ±1.5µs End-to-End Budget G.8271.1 Time Error Budget Example • e.g. Temporary GNSS jamming or poor line of sight • Duration : Few seconds – Few hours • Holdover budget – few hundred of nsec
- 9. © 2015 ADVA Optical Networking. All rights reserved. Confidential.9 Long Term Holdover • Antenna failure (e.g. lightening) • Few hours – 3 days • Depend on the available time error budget – but potentially can be more than 1500nsec
- 10. © 2015 ADVA Optical Networking. All rights reserved. Confidential.10 Oscillator Types – Aging and Temperature Stability Temperature Stability Aging/Day ≤10ppb ≤1ppb ≤0.1ppb ≤0.01ppb ≤0.001ppb ≤0.0001 ppb ≤1ppb≤0.1ppb≤0.01ppb≤0.001ppb≤0.0001ppb OCXO HQQ OCXO Rubidium X20 better Temperature Stability Vs Rb X10 better Aging Vs HQQ
- 11. © 2015 ADVA Optical Networking. All rights reserved. Confidential.11 It can be very cold… HUAWEI BS China 2008 winter storm Telenor base station or snow creature?
- 12. © 2015 ADVA Optical Networking. All rights reserved. Confidential.12 Or very hot… Telenor base station or snow creature?
- 13. © 2015 ADVA Optical Networking. All rights reserved. Confidential.13 And it can swing in between… • The greatest temperature change in 24 hours occurred in Loma, MT. on January 15, 1972. The temperature rose 56 degrees, from -47C degrees to 9C. • The greatest temperature change in 12 hours happened on December 14, 1924. The temperature at Fairfield, Montana, dropped from 17C to -29 at midnight
- 14. © 2015 ADVA Optical Networking. All rights reserved. Confidential.14 Environmental Condition • Synchronization devices at the access network are subject to wider temperature variation! • ETSI Environmental Classes: Class # Class description Temp. change rate Temp. change range Delta 3.6 Control room locations 0.5°C / min [+25, +30°C] 5°C 3.1 Temp. controlled locations 0.5°C / min [+25, +40°C] 15 3.2 Partly temp. controlled locations 0.5°C / min [+25, +55°C] 30 3.3 Not temp. controlled locations 0.5°C / min [-5, +45°C] 50 4.1 Non-weatherprotected locations 0.5°C / min [-10, +40°C] 50 3.5 Sheltered locations 1°C / min [-40, +40°C] 80 Core Access Ethernet Access NE - typical operational temperature range [-40, +65°C] Higher temperatures are expected in other continents
- 15. © 2015 ADVA Optical Networking. All rights reserved. Confidential.15 Oscillator Types Clock Type # Cost Operational Temperature range of the clock Typical Ambient Operational Temperature range of the Sync Element Temp Stability Aging/Day OCXO Low (10%) -40 to 85 C -40 to 65 C 1-10 ppb 1ppb OCXO HQ Medium (100%) -40 to 85 C -40 to 65 C 0.01 ppb 0.05 ppb Rubidium High (300%) -10 to +75 C -5 to +55 C 0.2 ppb 0.005 ppb Aging seem to be the only advantage of Rb But Aging can be estimated with GNSS! Rb High cost , limited operational temperature range and temperature instability make it less suitable for access devices
- 16. © 2015 ADVA Optical Networking. All rights reserved. Confidential.16 What Is The Optimal Solution? • GNSS , while available (prior to holdover) can be used for learning local oscillator characteristics • In order to be able to efficiently learn the oscillator aging the oscillator must have a very good temperature stability • The GNSS long term accuracy is better than 1e-12 (G.8272 require PRTC to be with +/-100 nsec from UTC) • Combining the high temperature stability of the high end oscillator with the GNSS reference can generate optimized solution in both performance and cost
- 17. © 2015 ADVA Optical Networking. All rights reserved. Confidential.17 Oven Test Setup PRTC/GM DUT 1PPS Steered Clock Cs RefTester 1PPS Free running Clock TIEFFO GPS
- 18. © 2015 ADVA Optical Networking. All rights reserved. Confidential.18 HQQ Vs Rb – Controlled Room (25-30C) • Tested in the Oven with controlled room profile • Phase Holdover over 48 hours below 200nsec ! Enter Holdover After locked to GPS for 2 days 2 days HQQ holdover below 200 nsec ! Temperature effects are seen in the Rb TIE 0 2 4 6 8 10 12 14 16 x104 Time [sec] 0 2 4 6 8 10 12 14 16 x104 Time [sec] -50 50 0 100 150 200 TIE[nsec]Temperature[C] 25 26 27 28 29 30
- 19. © 2015 ADVA Optical Networking. All rights reserved. Confidential.19 120 HQQ Vs Rb – Temp’ Controlled Room (25-40C) Temperature effects are seen in the Rb FFO Temperature effects are NOT seen in the HQQ FFO Temperature[C] 25 30 35 40 0 20 40 Time [Hours] 60 80 100 120 0 20 40 Time [Hours] 100 x10−10 FFO -0.5 0 0.5 1 1.5 2 2.5 3 12060 80
- 20. © 2015 ADVA Optical Networking. All rights reserved. Confidential.20 HQQ Vs Rb – Temp’ Controlled Room (25-40C) Temperature effects are seen in the Rb TIE Enter Holdover After locked to GPS for 2 days 2 days HQQ holdover below 1800nsec ! 2 days Rb holdover are above 13500 nsec ! 0 20 40 Time [Hours] 60 80 100 120x104 TIE[nsec] -2000 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Temperature[C] 25 30 35 40 0 20 40 Time [Hours] 60 80 100 120 Temperature effects are NOT seen in the HQQ TIE
- 21. © 2015 ADVA Optical Networking. All rights reserved. Confidential.21 HQQ Vs Rb – Temp’ Controlled Room (25-40C) Rb Fails PRC G.811 mask during holdover HQQ Meet PRC G.811 mask during holdover
- 22. © 2015 ADVA Optical Networking. All rights reserved. Confidential.22 HQQ Holdover at +/- 20C (0-40C) Enter Holdover 24 Hours 500ns • Tested in the Oven with temperature profile +/- 20C • Phase Holdover over 24 hours below 500nsec !
- 23. © 2015 ADVA Optical Networking. All rights reserved. Confidential.23 • Better operational temperature range and stability – guarantee better performance in the field • Cost Effective Solution – ~one third of the cost • Superior holdover performance with the aging learning algorithm enabled for High quality oscillator Advantages of the High Quartz Oscillator Over Rubidium 400nsec 1.1usec 1.5usec 5usec 10usec HQ Oscillator 15 hours ~1.3 days 2 days 4 days 6 days Rubidium benchmark NA NA 1 day 3 days 5 days
- 24. 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 this presentation. 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 or implied. 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.