Phase Delivery in Brownfield World at ITSF 2014
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Nir Laufer explores phase delivery in a brownfield world at ITSF 2014
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Phase Delivery in Brownfield World at ITSF 2014
- 1. Nir Laufer, ITSF 2014, Budapest Phase Delivery in Brownfield World
- 2. © 2014 ADVA Optical Networking. All rights reserved. Confidential.2 Basics: Brown Vs. Green Field Deployments • Green field lacks the constraints imposed by prior work • However in telecom, brownfield deployments are very common and operators all over the world are facing challenges designing the existing networks for accurate phase delivery
- 3. © 2014 ADVA Optical Networking. All rights reserved. Confidential.3 Frequency Synchronization G.8265.1 Centralized Architecture • End-to-End – IP Unicast T-GM GNSS PTP Grandmaster PTP Slave Clock PTP unaware Packet-Based Network T-SC 3G/4G Base Station / Small Cell IP Unicast 16ppb Frequency delivery using centralized End-to-End architecture – Can we use this architecture for phase delivery? ?! Asymmetry & PDV
- 4. © 2014 ADVA Optical Networking. All rights reserved. Confidential.4 Why Is Asymmetry an Issue? T1 – departure timestamp according to master PTP clock of first message called “sync message”. T2 – arrival timestamp according to slave PTP clock of sync message. T3 – departure timestamp according to slave PTP clock of second message called “delay request message”. T4 – arrival timestamp according to master PTP clock of delay request message. T2 = T1 + Delay_MS + Offset T4 = T3 + Delay_SM – Offset Symmetry:Delay_MS = Delay_SM = Delay Offset = ((T2-T1)-(T4-T3))/2 Asymmetry:Delay_MS != Delay_SM : Offset+(Delay_MS-Delay_SM)/2=(T2-T1)-(T4- T3))/2 SlaveMaster T1 T2 T3 T4 T4 Delay_MS Delay_SM Offset from Master
- 5. © 2014 ADVA Optical Networking. All rights reserved. Confidential.5 Green Field Deployments – G.8275.1 • Full on Path Support • Solving PDV and asymmetry uncertainties using full PTP on path support • All Boundary clocks based on G.8275.1 – PTP + Sync-E • Point to Point , Ethernet multicast Packet-Based Backhaul Network T-GM GNSS PTP Grandmaster & Sync-E PTP Slave Clock Slave Each network element needs to be PTP-aware (T-BC) with Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E BC & Sync-E 4G Base Station / Small Cell 16ppb & +/-1.1us Ethernet Multicast
- 6. © 2014 ADVA Optical Networking. All rights reserved. Confidential.6 G.8275.1 – Full On Path Support Advantages: • Fully standardized • Guaranteed performance – the PDV and asymmetry are controlled Disadvantages: • Costly – require Sync-E and Boundary Clock in each NE • Standardized for 1G/10G Ethernet interfaces but not for other commonly used technologies (OTN/MW/MPLS/PON) Can’t fully solve the phase delivery challenges in brownfield world!
- 7. © 2014 ADVA Optical Networking. All rights reserved. Confidential.7 GPS Transport unit Transport unit PTP Slave & Probe Grand Master GPS Network asymmetry of 14usec over single MW hop Example #1
- 8. © 2014 ADVA Optical Networking. All rights reserved. Confidential.8 GPS PTP Slave & ProbeGrand Master GPS Slave recovered clock without Transparent Clock (TC) enabled – 1500 nsec pk2pk Slave recovered clock with TC enabled – 55 nsec pk2pk Example #2
- 9. © 2014 ADVA Optical Networking. All rights reserved. Confidential.9 Phase Delivery Challenges in Brownfield Deployments • Existing network introduce high level of asymmetry and PDV • The asymmetry and PDV varies over time • Existing networks include different transport technologies • Upgrading/forklifting the existing NE to Sync-E/BC is very costly Do we really need frequency and phase in the core network?
- 10. © 2014 ADVA Optical Networking. All rights reserved. Confidential.10 Bypass the problem: Get the Grand Master closer to the Slave Use full on path support (if need) in the last mile Core/Mobile Backhaul Provider Mobile Network Operator High PDV/ Asymmetry PTP Slave Clock Slave 4G Base Station / Small Cell Grand Master GNSS The Solution
- 11. © 2014 ADVA Optical Networking. All rights reserved. Confidential.11 Grand Master GNSS Core/Mobile Backhaul Provider Mobile Network Operator High PDV/ Asymmetry PTP Slave Clock Slave 4G Base Station / Small Cell Packet-Based Backhaul Network Grand Master GNSS Bypass the problem: Get the Grand Master closer to the Slave Use full on path support (if need) in the last mile The Solution
- 12. © 2014 ADVA Optical Networking. All rights reserved. Confidential.12 Phase Delivery: Small Scale GM & G.8275.1 – Last Mile • G.8275.1 – Uses hop by hop , Ethernet multicast mini-GM Local Macro Base Station GNSS T-SC Core/Mobile Backhaul Provider Mobile Network Operator High PDV/ Asymmetry Packet-Based Backhaul Network PTP Slave Clock Slave Each network element needs to be PTP-aware (T-BC) with Sync-E BC & Sync-E BC & Sync-E BC & Sync-E 4G Base Station / Small Cell 16ppb & +/-1.1us Ethernet Multicast G.8275.1 Last mile full on path support Small Scale GM as a head of G.8275.1 chain
- 13. © 2014 ADVA Optical Networking. All rights reserved. Confidential.13 Phase Delivery: Small Scale GM & G.8275.2 – Last Mile • G.8275.2 – Uses IP unicast for phase delivery over last mile mini-GM Local Macro Base Station GNSS T-SC Core/Mobile Backhaul Provider Mobile Network Operator High PDV/ Asymmetry Packet-Based Backhaul Network PTP Slave Clock Slave 4G Base Station / Small Cell 16ppb & +/-1.1us G.8275.2 Small Scale GM as a head of G.8275.2 chain
- 14. © 2014 ADVA Optical Networking. All rights reserved. Confidential.14 Small Scale GM at Fibre Macro Site Extension over Microwave to Remote Site mini-GM Local Macro Base Station GNSS Remote Base Station Macro or Small Cell T-SC T-SC T-SC T-SC Mobile Backhaul Provider Mobile Network Operator Fibre Ethernet Access P2P Microwave Links to Macro Sites High PDV/ Asymmetry G.8275.1/2 + Optional Transparent Clock Small Scale GM as a head of G.8275.1/2 chain Optional Last mile full on path support using Transparent Clock
- 15. © 2014 ADVA Optical Networking. All rights reserved. Confidential.15 mini-GM GNSS Boundary Clock High Fan Out T-SC T-SC T-SC Server NICs Customer Rack Data Centre High PDV/ Asymmetry Core Network PTP PTP PTP Time as a Service into Data Centre Financial Markets, Health, Media Bring accurate time and frequency synchronization into data centers
- 16. © 2014 ADVA Optical Networking. All rights reserved. Confidential.16 Phase Delivery: Indoor Small Cells GNSS antenna Small Scale GM Core/Access PTP unaware Network GNSS antenna on the roof, Indoor Sync distribution using G.8275.1/2
- 17. © 2014 ADVA Optical Networking. All rights reserved. Confidential.17 Small Scale GM Protection How can the Small Scale GM be protected against local GNSS outage? Secondary sources 1) Sync-E (time holdover) for core network or adjacent PTP GM 2) PTP input (Slave) locked to core or adjacent PTP GM (APTS) • Can be used as secondary frequency and/or time source
- 18. © 2014 ADVA Optical Networking. All rights reserved. Confidential.18 T-GM GNSS PTP Grandmaster Packet-Based Backhaul Network PTP unaware or partly aware G.8265.1 /G.8275.2 Remote Base Station T-SC T-SC T-SCFirst Aggregation Node GNSS only at first aggregation site 1588v2 with Full/Partial On Path Support to Cell Sites APTS in case of GNSS failure Boundary Clock & PTP fully aware or partly aware network G.8275.1/G.8275.2 BC GNSS APTS mini-GM Small Scale GM with APTS in Aggregation Node – Core GM Protection
- 19. © 2014 ADVA Optical Networking. All rights reserved. Confidential.19 Remote Base Station T-SC T-SC T-SC First Aggregation Node Boundary Clock & PTP fully aware or partly aware network GNSS APTS mini-GM High PDV/ Asymmetry Remote Base Station T-SC T-SC T-SC Boundary Clock & GNSS APTS mini-GM First Aggregation Node Core/Mobile Backhaul Provider Mobile Network Operator Sync-E/PTP/Sync-E+PTP Sync-E/PTP/Sync-E+PTP Small Scale GM with APTS in Aggregation Node – Adjacent GM Protection Adjacent Small Scale GM protect one anther
- 20. © 2014 ADVA Optical Networking. All rights reserved. Confidential.20 APTS KPIs and SLA • Low Scale GM includes Primary Reference Time Clock (PRTC) which filter the GNSS input • The PRTC is very accurate time reference – time error within +/- 100nsec from UTC (G.8272) • This accurate reference can be used for the validation of the secondary references: • PRTC Vs. PTP Slave recovered clock (PTP Input) • Total/Constant/Dynamic Time Error (TE) Vs predefined threshold • MTIE Vs predefined mask • Network asymmetry and PDV • PRTC Vs. Sync-E • MTIE Vs predefined mask • The results and failure alarms should be collected by the NMS.
- 21. © 2014 ADVA Optical Networking. All rights reserved. Confidential.21 OSA 5410 Requirements for Small Scale GM + APTS • Low cost solution is needed in order to deliver cost effective solution in large scale deployment • Integrated GNSS, Sync-E, PTP GM/BC/Slave , Probe in one box • Support PTP GM ,Slave and Sync-E simultaneously • Sync Probing and assurance of Sync inputs for synchronization protection validation
- 22. © 2014 ADVA Optical Networking. All rights reserved. Confidential.22 Cost GNSS everywhere Small Scale GM PTP full on path support everywhere PTP Support High Low None Full Business Case: Small Scale GM vs. GNSS Everywhere • Only one GNSS antenna is needed every N base stations (I.e. N=4..64) • (Cost of small scale GM divided by N + one antenna installation) << ( N x Cost of GNSS antenna installation )
- 23. © 2014 ADVA Optical Networking. All rights reserved. Confidential.23 OSA 5411 Summary – Brownfield Deployments Meeting the stringent Phase synchronization requirements is possible in brownfield deployments! • Get the master closer to the slave! • Lower PDV • Lower asymmetry • If needed use Full on path support BC/TC only in last mile • APTS - Improve Robustness & Protection by use Sync- E/PTP/PTP+Sync-E from core GM or adjacent small scale GM to protect GNSS outages • Use the GNSS while available to monitor and assure the quality of the secondary synchronization source (i.e. Sync-E , PTP input)
- 24. Nlaufer@advaoptical.com Questions? 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.