A challenge towards disaggregation of time-critical PON function

Transcription

1 A challenge towards disaggregation of time-critical PON function - Introduction of DBA-API and its demo for 5G use case - Kota Asaka NTT Project Steam Leader of PON abstraction interface for time-critical applications 1

2 Contents Background Why do we need disaggregation of time-critical function? Standardization at BBF Prototype demo of DBA-API for 5G MFH over NG-PON2 Summary 2

3 Broadband subscribers in Japan FTTH service is widely deployed in Japan (>30M subscribers). Number of mobile (LTE) users are rapidly increasing. Subscribers (M) From Annual report of ICT by Ministry of Internal Affairs and Communications, Japan 3

4 New broadband strategy in NTT NTT had changed the broadband business strategy from B2C (Business to Consumer) to B2B2C (Business to Business to Consumers). In 2015, we started wholesaling fiber access according to this strategy. This business model is called Hikari Collaboration Model. 4

5 FTTH subscribers in NTT A number of FTTH subscribers in NTT reached >20M subscribers. The numbers of subscriber over FTTH wholesale service are rapidly increasing. Business partners are M(V)NOs, ISPs, local CATV operators, video distribution SPs, local gas/electric power providers, retailers, manufacturers, and others Hikari Collaboration (B to B to C) Flet's Hikari (B to C) Mar 2012 Mar 2013 Mar 2014 Mar 2015 Mar 2016 Mar 2017 Mar From NTT Financial report, 5

6 Requirements of future optical access system NTT changed the strategy; From: to provide broadband uniformly, To: to maximize the value for each service provider and customer. The system must have flexibility and agility to address emerging services. Conventional access system Requirements Future Purpose and vender specified implementation A lot of restrictions in adding/replacing functions High flexibility Accommodate to various service levels Promptly add/replace functions Difficult to drastically reduce cost of dedicated equipment Necessity of maintenance skills and spare equipment for each dedicated system High universally CAPEX reduction by constructing systems on demand OPEX reduction due to minimization of spare equipment and simplification of operation procedures 6

7 Requirements of future optical access system Network functions modularization; Disaggregation of conventional access equipment/system Most of the required access functions can be achieved by software components as VNF with the use of commodity hardware. Software components lead to flexible and early time-to-market development. Commodity hardware results in cost reduction. 7

8 R -Flexible Access System Architecture- In order to enable a more diverse range of services provided quickly and at a low cost, NTT launched a new concept of FASA in FASA aims to serve customers and service providers who use access networks and wish to begin using or providing services immediately. Today Purpose-specified OLT Difficult to add/change functions promptly OLT FASA virtual OLT concept Wavelength control Service achieved through the combination of modularized functions New Function Vender proprietary architecture and functional blocks residential customers Purpose specified implementation Bandwidth control OAM Multicast Generic hardware External module (WDM/TDM- PON) WDM/TDM PON OLT: Optical Line Terminal, : Optical Network Unit WDM/TDM-PON: Wavelength Division Multiplexing / Time Division Multiplexing - Passive Optical Network OAM: Operations Administration and Maintenance (Generic functions)... External module (EPON) Add/change new software functions Replace hardware module to meet transmission requirements NTT Press Release, Introducing the New FASA Concept for Future Access Systems, Feb 8,

9 Example of FASA Video camera Video recognition service Power splitter External HW module (MPCP function) 10G-EPON OLT (Commodity server w/ SW-based PON functions) NTT R&D Forum 2018, Flexible Access System Architecture (FASA) enabling provision of value-added services, Feb 22-23, 2018, Tokyo. 9

10 Challenge towards disaggregation of time-critical functions FASA will follow existing architecture/interface specifications and OSSs (BBF, ONF, etc). In addition, we are trying further disaggregation in order to achieve flexibility and agility even in time-critical functions (e.g. DBA) by updating/replacing a software component. PS CO OLT SR-DBA v.1.0 SR-DBA v.2.0 CO: Central Office DBA: Dynamic Bandwidth Assignment PS: Power Splitter SR: Status Report Flexible function update by software update K. Asaka and J. Kani, Contribution in FSAN Louisville meeting, June

11 Use case - 5G mobile fronthaul (MFH) over TDM-PON - In 5G mobile system, dense small cells could be accommodated by a PON as MFH, which has an advantage in terms of low CAPEX of physical infrastructure. By replacing the DBA software from SR-DBA to CO-DBA, TDM-PON-based MFH can be realized. This avoids re-building the OLT from the beginning. Share one feeder fiber CU RU PS CO OLT SR-DBA for FTTH CU: Central Unit DBA: Dynamic Bandwidth Allocation LL: Low-latency OLT: Optical Line Terminal PS: Power Splitter RU: Radio Unit SR-DBA: Status-reporting DBA CO-DBA: Cooperative DBA RU RU Share one physical interface K. Asaka and J. Kani, Contribution in FSAN Louisville meeting, June CO-DBA for 5G MFH Agile service adaptation by software replacement 11

12 Standardization at BBF Project Stream PON abstraction Interface for Time-Critical Applications (TCA) is discussing the related specifications in FAN WA of BBF. The project focuses on the disaggregation of TCA to achieve agility and flexibility even in TCAs (e.g. DBA). Differentiation part (Software) Replacement upon service requirement Algorithm A Algorithm B Access Node PNF1 PNF2 PNFn API: Application Programmable Interface PNF: Physical Network Function API Common behavior To be specified by WT-402/403 12

13 TCA example (1) SR-DBA in WT-402 When using DBA as a TCA, processing delay should be much less than DBA cycle (N x 125 µs). Otherwise, DBA delay increases by 125-µs period. Therefore, the interfaces to tell CPU of Report, and the one to designate Grant from CPU are time-critical. GRANT for ONT1&2 REPORT info DBA cycle: 2 x 125µs REPORT (BufOcc) Data arrival processing delay (calculates schedule) GRANT for ONT3&4 DBA delay@ont From BBF contribution (bbf ) by H. Ujikawa, K. Asaka, and B. Nagel for Taipei meeting, May GRANT info REPORT info for all ONTs next DBA cycle (2 x 125µs) GRANT for 1&2 Data (Upstream) REPORT +DATA ONT1 ONT2 ONT3 ONT4 OLT App Control Data (Upstream) time@cpu time@olt time@ont1 13

14 TCA example (2) CO-DBA in WT-402 For MFH, the summation of DBA delay and propagation delay should be shorter than 250 µs. Data request copy scheduling info processing delay (translation) GRANT info GRANT front haul requirement < 250 µs DBA delay DATA UE1 RU1 Data (Upstream) ONT1 ONT2 OLT App ONT Control scheduling info[2] scheduler UE Control From BBF contribution (bbf ) by H. Ujikawa, K. Asaka, and B. Nagel for Taipei meeting, May From BBF contribution (bbf ) by H. Ujikawa, K. Asaka, and B. Nagel for Taipei meeting, May CU+DU(BBU) Data (Upstream) 14

15 Functional requirements of DBA-API in WT-402 A-1: API to grant transmission (to construct BWmap) with precise time designation. A-2: API to get status reports (to get BufOcc) with precise time designation. A-3: API to read scheduling information sent from external system. A-4: API to notify the requesting and/or granting information in PON to external system From BBF contributions; bbf by H. Ujikawa, K. Asaka, M-F. Chang, C-K Chen, and K. Yamamoto for conference call, Jul., bbf by H. Ujikawa, and K. Asaka for Helsinki meeting, Sep.,

16 Deliverables of TCA project Under SB. SB/FB comment resolutions at Q2/Q3 meetings expected. SB: Straw Ballot FB: Final Ballot SB planned right after Q2 meeting. SB/FB comment resolutions at Q3/Q4 meetings expected. Disaggregation policy Use cases functional requirements for APIs (DBA and DWA) Detail specifications of APIs (format and performance requirements) 16

17 Prototype demo of DBA-API (WT-402/403) Different DBA software on each OLT box with the same specs including DBA-API. With low-latency DBA, the maximum upstream latency between DU and CU is successfully suppressed to less than 100 us. video traffic Upstream latency typical latency < 2ms SR-DBA for FTTH CO-DBA for mobile low latency < 100us time CU+DU (BBU) Latency monitor Cooperative IF OLT CO-DBA for mobile OLT SR-DBA for FTTH RU (RRH) UE PC CO-DBA: Cooperative DBA SR-DBA: Status-reporting DBA CU: Central unit DU: Distributed unit RU: Radio unit RRH: Remote Radio Head BBU: Base Band Unit 17

18 Demo announcement Time: 10:40-11:10 Coffee break 12:30-14:00 Lunch break Venue: Room ALTAIR on the 2nd floor (Coffee break room) 19

19 Standardization map for 5G MFH over NG-PON2 Action required! How Cooperative IF will be specified by collaborating with Mobile SDO? Under discussions at Get involved! OLT Controller G.989 CU Cooperative IF WT-402/403 This work! CO-DBA for mobile OLT G.989 PON IF ONT RU 20

20 Summary SDN/NFV technologies in access system will lead to more flexible and agile service adaptation for emerging services. Cloud CO at BBF, R-CORD at ONF, and FASA should be great driving forces moving forward to such a future access system. In order to achieve flexibility and agility even in time-critical functions, BBF is working for standardization. 21

21 More at broadband-forum.org/pon-ai-for-tca 22