What is the future of traditional SSUs and TSGs?
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Chuck Perry’s WSTS presentation discussed the concept of building integrated timing supply (BITS) and explored how maintaining existing synchronization infrastructure has created difficulties for this approach. He looked at modern timing technologies not supported by SSU/TSGs and outlined the urgent need for core clocks capable of supporting both legacy and all new sync technologies for packet networks in a common shelf.
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What is the future of traditional SSUs and TSGs?
- 1. What is the future of traditional SSUs and TSGs? WSTS, March 2019 Chuck Perry, director, business development, North America, Oscilloquartz
- 2. © 2019 ADVA Optical Networking. All rights reserved.22 Existing deployments for TDM synchronization BITS clocks GPS PRS Cs PRS Free-running self- contained stratum 1 frequency source E1/T1 10Mhz Outputs GPS-based stratum 1 frequency source E1/T1 10Mhz outputs Possible NTP/TOD Redundant frequency distribution shelf with holdover protection DS1/E1, CC Possibly Integrated GPS Possible NTP/PTP
- 3. © 2019 ADVA Optical Networking. All rights reserved.33 “Building integrated timing supply” Following the BITS concept means that all “network elements” within an office be timed from a single common clock source TSGs and SSUs fill this role Traditional TSG/SSU architecture – employs dual clock modules within a common shelf, dual feeding a bank of output modules (E1,DS1 or CC) Network elements are designed accept primary and secondary timing inputs from diverse output modules creating a “no single point of failure” scenario What is the BITS concept?
- 4. © 2019 ADVA Optical Networking. All rights reserved.44 10s of thousands of SSU/TSGs deployed in NA
- 5. © 2019 ADVA Optical Networking. All rights reserved.55 ANSI clock standards Stratum-1 Stratum-2 Stratum-3E Stratum-3 1 x 10-11 1.6 x 10-8 4.6 x 10-6 Not defined < 255 DS1 slips, 1st 24 hrs 1 x 10-10 per day, 1st 24 hrs 4.6 x 10-6 1 x 10-8 per day, 1st 24 hrs 1.6 x 10-8 Not defined 4.6 x 10-6 4.6 x 10-6 SMC 2.0 x 10-5 Stratum-4 Not defined3.2 x 10-5 3.2 x 10-5 4.6 x 10-6 2.0 x 10-5 The maximum MTIE during a reference rearrangement for SONET interfaces is 1ms or 20ns in any 14ms
- 6. © 2019 ADVA Optical Networking. All rights reserved.66 Many of these clocks are still in place with many serving mission-critical applications in the federal, telco, cable and utilities markets Providing DS1 timing to SONET and TDM transport gear Providing “composite clock” timing to channel banks and signaling gear as required for critical applications like emergency “911” service Important note! Maintaining legacy SSUs/TSGs has forced operators to “abandon the BITS concept” because these clocks are not capable of providing all of the synchronization needs of modern offices and networks! Where are all these clocks today?
- 7. © 2019 ADVA Optical Networking. All rights reserved.77 © 2018 ADVA Optical Networking. All rights reserved. Confidential.7 1) Sync-E inputs and outputs 2) PTP grandmaster, slave and boundary clock functionality 3) PTP to NTP translation 4) Using PTP inputs for protection against local GNSS jamming 5) In-service PTP probing for sync assurance and advanced spoofing detection 6) NTP/PTP/Sync-E service port expansion capabilities with faster interfaces 7) ePRTC – enhanced primary reference time clock 8) Maintaining legacy TDM sync network using traditional TSG architecture Synchronization needs for modern network clocks
- 8. © 2019 ADVA Optical Networking. All rights reserved.88 Synchronous Ethernet Synchronous Ethernet, also referred to as Sync-E, is an ITU-T standard for computer networking that facilitates the transference of frequency reference signals over the Ethernet physical layer. This signal can then be made traceable to an external clock.
- 9. © 2019 ADVA Optical Networking. All rights reserved.99 9 What is a modern boundary clock? PTP UDP IP MAC PHY MII PTP UDP IP MAC PHY MII PTP UDP IP MAC PHY MII PTP UDP IP MAC PHY MII Slave Master IP network Grandmaster Boundary clock Boundary clock Slave Grandmaster Boundary clock Slave Modern clocks can use boundary clock functionality as a backup or alternative to GNSS for UTC traceable reference Why limit downstream service to PTP? Once the clock is set it can be used for BITS, Sync-E, PTP profile conversion, PTP/NTP translation etc … A boundary clock has an internal oscillator and can extend the reach, and/or offload slave capacity from the PTP grandmaster M S M MS S
- 10. © 2019 ADVA Optical Networking. All rights reserved.1010 Rather than sending NTP across the network, much better results can be achieved by sending PTP across the network, then translating to NTP at the end office where the NTP service is required NTP client GNSS PTP to NTP translation PTP to NTP Core/mobile backhaul provider NTP BCTC PTP Grandmaster PTP PTP packets NTP packets
- 11. © 2019 ADVA Optical Networking. All rights reserved.1111 11 Local GNSS jamming is a real threat!
- 12. © 2019 ADVA Optical Networking. All rights reserved.1212 Using PTP for protection against local GNSS jamming GNSS primary active T Routed network All slaves remain locked to primary GM GNSS still traceable through PTP backup PTP G8275.2 PRS PTP secondary PTP secondary PTP G8275.2 PTP G8275.2 PTP G8275.2 Active PRS PRS Active GNSS primary active Primary grandmaster Secondary grandmaster GPS jammer Modern clock server GM with PTP inputs Modern clock server GM with PTP inputs
- 13. © 2019 ADVA Optical Networking. All rights reserved.1313 GNSS primary active T Routed network All slaves remain locked to primary GM GNSS still traceable through PTP backup PTP G8275.2 PRS PTP secondary PTP secondary PTP G8275.2 PTP G8275.2 PTP G8275.2 Active PRS PRS Active GNSS primary active Primary grandmaster Secondary grandmaster GPS jammer Using PTP for protection against local GNSS jamming Modern clock server GM with PTP inputs Modern clock server GM with PTP inputs
- 14. © 2019 ADVA Optical Networking. All rights reserved.1414 GNSS primary T Routed Network All Slaves remain locked to Primary GM. GNSS still traceable through PTP backup PTP G8275.2 PRS PTP secondary active PTP secondary PTP G8275.2 PTP G8275.2 PTP G8275.2 Active PRS PRS Active GNSS primary active Primary grandmaster Secondary grandmaster Routed network All slaves remain locked to Primary GM GNSS still traceable through PTP backup GPS jammer Using PTP for protection against local GNSS jamming Modern clock server GM with PTP inputs Modern clock server GM with PTP inputs
- 15. © 2019 ADVA Optical Networking. All rights reserved.1515 GNSS primary T Routed Network All Slaves remain locked to Primary GM. GNSS still traceable through PTP backup PTP G8275.2 PRS PTP secondary active PTP secondary PTP G8275.2 PTP G8275.2 PTP G8275.2 Active PRS PRS Active GNSS primary active Primary grandmaster Secondary grandmaster Routed network All slaves remain locked to primary GM GNSS still traceable through PTP backup GPS jammer Using PTP for protection against local GNSS jamming Modern clock server GM with PTP inputs Modern clock server GM with PTP inputs
- 16. © 2019 ADVA Optical Networking. All rights reserved.1616 GNSS primary active T Routed network All slaves remain locked to primary GM GNSS still traceable through PTP backup PTP G8275.2 PRS PTP secondary PTP secondary PTP G8275.2 PTP G8275.2 PTP G8275.2 Active PRS PRS Active GNSS primary active Primary grandmaster Secondary grandmaster GPS jammer Using PTP for protection against local GNSS jamming Modern clock server GM with PTP inputs Modern clock server GM with PTP inputs
- 17. © 2019 ADVA Optical Networking. All rights reserved.1717 In-service PTP clock probing PTP clock probes can be used for probing of PTP packet timing signals for sync assurance and slave clock recovery validation Clock analysis is done based on timestamps embedded in the PTP packets, compared to a reference signal (i.e. GPS) Packet TE/TIE/MTIE can be computed for multiple in-service probes In case of packets/reference failure or in case MTIE mask crossed, in-service probing can raise alarms and generate SNMP traps
- 18. © 2019 ADVA Optical Networking. All rights reserved.1818 Detecting clock drift caused by spoofing Requires majority voting and comparison of three independent sources minimum. Any three of the following: 18 1) Cesium 2) GPS 3) GLONASS 4) Galileo 5) BEIDOU
- 19. © 2019 ADVA Optical Networking. All rights reserved.1919 Using PTP probing for advanced spoofing detection GALILEO T PTP G8275.2 PTP G8275.2 Routed network GLONASSGPS PTP G8275.2PTP G8275.2 PTP G8275.2 PTP G8275.2 Grandmaster #1 Grandmaster #2 Grandmaster #3 PTP Probe GM3 T3 Vs GPS PTP Clock Probe GM1 T3 Vs GPS PTP Clock Probe GM2 T3 Vs GNS PTP Clock Probe GM4 T3 Vs GAL PTP Clock Probe GM0 T3 Vs GAL PTP Clock Probe GM2 T3 Vs GAL Use PTP clock probing and majority voting to detect clock drift between adjacent GMs Alternate GNSS constellations can be used (GPS, GLONASS, GALILEO or BEIDOU) GALILEO GM with IS PTP probing GM with IS PTP probing GM witGM with IS PTP probing
- 20. © 2019 ADVA Optical Networking. All rights reserved.2020 Time is money $$$! Operators are upgrading their networks to be PTP capable in order to deliver accurate phase required for RAN applications (LTE-A/LTE-TDD) TAAS – accurate time/frequency delivered via PTP can be a profitable service offering for the mobility, financial and other markets Core routing equipment no longer supports 1G interfaces – 10G clock interfaces are now required from core clocks to minimize PTP hop counts and enable efficient PTP distribution from the core NTP/PTP/Sync-E port expansion and faster interfaces Timing as a service is a new potential source of revenue for many operators $$$
- 21. © 2019 ADVA Optical Networking. All rights reserved.2121 ePRTC: enhanced PRTC (ITU-T G.8272.1) Cesium clock to filter GNSS instabilities: • Atmospheric interference • Solar storms • Equatorial diurnal Ionospheric variation 30ns MTIE in GNSS locked mode Cesium clock: resiliency against GNSS outage 100ns MTIE over 14 days in holdover mode (Class-A) 100ns MTIE over 80 days in holdover mode (Class-B) MTIE τ(s) 15ns 100ns 1ns 0.1 1 10 100 400k1k 10k 10ns 100k 1M 10M 100M 30ns 4ns 30 ns 30 ns 100 ns 4ns What is needed? A modern clock that can offer "single shelf solution" to combine with cesium to achieve ePRTC performance? Modern clock Cesium ePRTC
- 22. © 2019 ADVA Optical Networking. All rights reserved.2222 Traditional SSU/TSG architecture for mission-critical TDM applications will be required for many more years to come Operators have been forced to abandon the BITS concept due to the slow evolution of clocks capable of doing everything in a common shelf Combining all synchronization technologies in a common clock shelf is an important need for operators The industry is ready for a clock capable of enabling seamless evolution from TDM sync, to the highest precision PTP-based phase synchronization solutions Maintaining the BITS concept requires new modern core clocks capable of delivering legacy and all latest synchronization technologies for packet networks in a common shelf Summary – the problems our customers are facing
- 23. © 2019 ADVA Optical Networking. All rights reserved.2323 Multi-technology clock synchronization: Supporting traditional TSG architecture, SyncE, PTP, NTP, in-service probing, ePRTC and multi-constellation GNSS Scalable to meet future technology and expansion needs: Up to 160 BITS outputs supported Up to 48 1G or 10G service interface ports are supported OSA 5440: the future of the BITS concept lives on! Addressing all modern and legacy synchronization needs OSA 5440 From physical interfaces (BITS, Ethernet) to packet-based synchronization (NTP, PTP) Sync technology evolution New! Come visit the OSA booth today!
- 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. Chuck Perry cperry@oscilloquartz.com