Recommendation ITU-T G.989.3 (05/2021) 40-Gigabit-capable passive optical networks (NG-PON2): Transmission convergence layer specification
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
4 Abbreviations and acronyms
5 Conventions
6 NG-PON2 transmission convergence layer overview
     6.1 TWDM transmission convergence layer
          6.1.1 Supported nominal line rates
          6.1.2 TWDM TC layer structure
          6.1.3 TWDM TC sublayer functions
               6.1.3.1 TWDM TC service adaptation sublayer
               6.1.3.2 TWDM TC framing sublayer
               6.1.3.3 TWDM TC PHY adaptation sublayer
          6.1.4 Management of a TWDM PON system
               6.1.4.1 Embedded OAM
               6.1.4.2 PLOAM channel
               6.1.4.3 ONU management and control channel (OMCC)
               6.1.4.4 ICTP
          6.1.5 Time and wavelength division multiplexing architecture
               6.1.5.1 Overview
               6.1.5.2 NG-PON2 system identifier
               6.1.5.3 PON-ID
               6.1.5.4 Downstream wavelength channel identifier
               6.1.5.5 Upstream wavelength channel identifier
               6.1.5.6 ONU identifier
               6.1.5.7 Allocation identifier (Alloc-ID)
               6.1.5.8 XGEM port identifier
               6.1.5.9 Channel partition index
          6.1.6 Media access control
     6.2 PtP WDM AMCC transmission convergence layer overview
          6.2.1 AMCC TC layer structure
          6.2.2 AMCC TC sublayer functions
               6.2.2.1 AMCC TC management service adaptation sublayer
               6.2.2.2 AMCC TC framing sublayer
               6.2.2.3 AMCC TC PHY adaptation sublayer
          6.2.3 AMCC TC management functions
7 TWDM resource allocation and quality of service
     7.1 Principles of downstream and upstream resource allocation
          7.1.1 Forms of traffic descriptor
          7.1.2 Traffic descriptor constraints
     7.2 Dynamic bandwidth assignment overview
          7.2.1 TWDM channel DBA abstraction
          7.2.2 DBA functional requirements
          7.2.3 DBA methods
          7.2.4 DBA engine
     7.3 Reference model of dynamic bandwidth assignment
          7.3.1 Summary of notation
          7.3.2 Offered traffic load
          7.3.3 Components of assigned bandwidth
          7.3.4 Guaranteed bandwidth assignment
          7.3.5 Rate-proportional assignment of additional bandwidth
          7.3.6 Additional bandwidth assignment based on priority and weights
          7.3.7 Timing control of assigned bandwidth
     7.4 DBA performance requirements
          7.4.1 Stationary bandwidth assignment
          7.4.2 Assured bandwidth restoration time
          7.4.3 DBA convergence time
8 NG-PON2 transmission convergence framing sublayer
     8.1 TWDM transmission convergence framing sublayer
          8.1.1 Downstream TWDM TC framing
               8.1.1.1 HLend structure
               8.1.1.2 BWmap partition
                    8.1.1.2.1 Alloc-ID field
                    8.1.1.2.2 Flags field
                    8.1.1.2.3 StartTime field
                    8.1.1.2.4 GrantSize field
                    8.1.1.2.5 Forced wake-up indication (FWI) bit
                    8.1.1.2.6 BurstProfile field
                    8.1.1.2.7 HEC field
               8.1.1.3 BWmap construction and parsing rules
               8.1.1.4 PLOAMd partition
               8.1.1.5 FS frame trailer
          8.1.2 Upstream TWDM TC framing
               8.1.2.1 Upstream FS header
                    8.1.2.1.1 ONU-ID field
                    8.1.2.1.2 Ind field
                    8.1.2.1.3 HEC field
                    8.1.2.1.4 Upstream PLOAM (PLOAMu) field
               8.1.2.2 Allocation overhead
                    8.1.2.2.1 BufOcc field
                    8.1.2.2.2 CRC field
               8.1.2.3 Upstream FS burst trailer
     8.2 PtP WDM management framing sublayer
          8.2.1 PLOAM count
          8.2.2 Payload length
          8.2.3 SFC offset
          8.2.4 Ind field
          8.2.5 HEC field
          8.2.6 PLOAM partition
          8.2.7 PtP WDM management frame trailer
9 TWDM encapsulation method
     9.1 XGEM framing
          9.1.1 FS payload structure
          9.1.2 XGEM frame header
          9.1.3 XGEM payload format
          9.1.4 Idle XGEM frame
     9.2 XGEM frame delineation
     9.3 SDU fragmentation
     9.4 Mapping of services into XGEM frames
          9.4.1 Ethernet over XGEM
          9.4.2 MPLS over XGEM
10 NG-PON2 PHY adaptation sublayer
     10.1 TWDM PHY adaptation sublayer
          10.1.1 Downstream PHY frame
               10.1.1.1 Downstream physical synchronization block (PSBd)
                    10.1.1.1.1 Physical synchronization sequence (PSync)
                    10.1.1.1.2 Superframe counter structure
                    10.1.1.1.3 Operation control structure
               10.1.1.2 PSBd field scrambling
               10.1.1.3 ONU downstream synchronization
               10.1.1.4 Downstream PHY frame payload
          10.1.2 Upstream PHY frames and upstream PHY bursts
               10.1.2.1 Upstream physical synchronization block (PSBu)
               10.1.2.2 Upstream PHY burst payload
               10.1.2.3 Guard time
          10.1.3 Forward error correction
               10.1.3.1 Downstream FEC
                    10.1.3.1.1 Downstream FEC codeword
                    10.1.3.1.2 Downstream FEC on/off control
               10.1.3.2 Upstream FEC
                    10.1.3.2.1 Upstream FEC codeword
                    10.1.3.2.2 Shortened last codeword
                    10.1.3.2.3 BWmap considerations
                    10.1.3.2.4 Upstream FEC on/off control
          10.1.4 Scrambling
               10.1.4.1 Scrambling of the downstream PHY frame
               10.1.4.2 Scrambling of the upstream PHY burst
     10.2 PtP WDM management PHY adaptation sublayer
          10.2.1 PtP WDM management PHY frame
               10.2.1.1 Physical synchronization block (PSB)
                    10.2.1.1.1 Superframe counter structure
                    10.2.1.1.2 Operation control structure
               10.2.1.2 AMCC frame synchronization
          10.2.2 Forward error correction
          10.2.3 Transcoding
11 NG-PON2 PLOAM messaging channel
     11.1 Overview
          11.1.1 PLOAM channel functionality
          11.1.2 PLOAM channel rate limitations
          11.1.3 PLOAM channel robustness
          11.1.4 Extensibility
     11.2 PLOAM message format
          11.2.1 ONU-ID
          11.2.2 Message type ID
          11.2.3 SeqNo
          11.2.4 Message content
          11.2.5 Message integrity check
          11.2.6 Common elements of PLOAM message format
               11.2.6.1 Vendor_ID
               11.2.6.2 VSSN
               11.2.6.3 Correlation tag
               11.2.6.4 Calibration record status
               11.2.6.5 Tuning granularity
               11.2.6.6 One-step tuning time
               11.2.6.7 Attenuation
               11.2.6.8 Power levelling capability
     11.3 PLOAM message definitions
          11.3.1 Downstream PLOAM message summary
          11.3.2 Upstream PLOAM message summary
          11.3.3 Downstream PLOAM message formats
               11.3.3.1 Burst_Profile message
               11.3.3.2 Assign_ONU-ID message
               11.3.3.3 Ranging_Time message
               11.3.3.4 Deactivate_ONU-ID message
               11.3.3.5 Disable_Serial_Number message
               11.3.3.6 Request_Registration message
               11.3.3.7 Assign_Alloc-ID message
               11.3.3.8 Key_Control message
               11.3.3.9 Sleep_Allow message
               11.3.3.10 Calibration_Request message
               11.3.3.11 Adjust_Tx_Wavelength message
               11.3.3.12 Tuning_Control message
               11.3.3.13 System_Profile message
               11.3.3.14 Channel_Profile message
               11.3.3.15 Protection_Control message
               11.3.3.16 Change_Power_Level message
               11.3.3.17 Power_Consumption_Inquire message
               11.3.3.18 Rate_Control message
               11.3.3.19 Reboot_ONU message
          11.3.4 Upstream PLOAM message formats
               11.3.4.1 Serial_Number_ONU message
               11.3.4.2 Registration message
               11.3.4.3 Key_Report message
               11.3.4.4 Acknowledgement message
               11.3.4.5 Sleep_Request message
               11.3.4.6 Tuning_Response message
               11.3.4.7 Power_Consumption_Report message
               11.3.4.8 Rate_Response message
12 NG-PON2 ONU activation
     12.1 TWDM PON ONU activation cycle
          12.1.1 Overview
          12.1.2 Activation outline
          12.1.3 Causal sequence of activation events
          12.1.4 TWDM ONU activation cycle state machine
               12.1.4.1 States, timers and inputs
               12.1.4.2 ONU state diagram
               12.1.4.3 ONU state transition table
          12.1.5 OLT support of the TWDM ONU activation
          12.1.6 ONU power levelling
               12.1.6.1 ONU-activated power levelling
               12.1.6.2 OLT-activated power levelling
     12.2 PtP WDM ONU activation cycle
          12.2.1 Causal sequence of activation events
          12.2.2 PtP WDM ONU activation cycle state machine
               12.2.2.1 Applicability of TWDM ONU activation states, timers and inputs to PtP WDM
               12.2.2.2 ONU state diagram
               12.2.2.3 ONU state transition table
13 NG-PON2 OLT and ONU timing relationships
     13.1 TWDM ONU transmission timing and equalization delay
          13.1.1 Timing of ONU upstream transmissions
          13.1.2 Timing relationships and quiet window during serial number acquisition
          13.1.3 Timing relationships and quiet window during ranging
          13.1.4 Calculating the equalization delay
          13.1.5 Timing relationships during operation
          13.1.6 In-service equalization delay adjustment
          13.1.7 Quiet window implementation considerations
          13.1.8 Fibre distance measurement
     13.2 Time of day distribution over TWDM Channel
          13.2.1 Notation
          13.2.2 ONU clock synchronization process
          13.2.3 Performance analysis
               13.2.3.1 Equalization delay accuracy
               13.2.3.2 Fibre propagation delay
               13.2.3.3 Internal timing corrections
     13.3 PtP WDM ONU transmission timing
14 TWDM performance monitoring, supervision and defects
     14.1 Performance monitoring
     14.2 Defects
          14.2.1 Items detected at OLT channel termination
          14.2.2 Items detected at ONU
          14.2.3 Urgent ONU status snapshot record
15 TWDM security
     15.1 Threat model for NG-PON2
     15.2 Authentication
          15.2.1 Registration-based authentication
               15.2.1.1 The OLT CT perspective
               15.2.1.2 The ONU perspective
          15.2.2 Secure mutual authentication options
     15.3 Key derivation
          15.3.1 Cryptographic method
          15.3.2 Master session key
          15.3.3 Derived shared keys
     15.4 XGEM payload encryption system
          15.4.1 Cryptographic method
          15.4.2 Secret key selection
          15.4.3 Initial counter block
     15.5 Data encryption key exchange and activation mechanism
          15.5.1 Overview
          15.5.2 Cryptographic method
          15.5.3 Unicast encryption
               15.5.3.1 Sequence of encryption key exchange and activation events
               15.5.3.2 OLT CT states and state diagram
               15.5.3.3 ONU states and state diagram
          15.5.4 Downstream multicast encryption
     15.6 Integrity protection and data origin verification for PLOAM
          15.6.1 Cryptographic method
          15.6.2 MIC calculation
     15.7 Integrity protection and data origin verification for OMCI
          15.7.1 Cryptographic method
          15.7.2 MIC calculation
     15.8 Integrity and data origin verification key switching
          15.8.1 Use of the default key
          15.8.2 Key switching for OMCI-based secure mutual authentication
          15.8.3 Key switching for IEEE 802.1x-based authentication
          15.8.4 MIC failure considerations
     15.9 NG-PON2 systems with reduced data encryption strength
          15.9.1 Effective key length
          15.9.2 Data encryption key format
16 NG-PON2 power management
     16.1 TWDM power management
          16.1.1 Power management configuration and signalling
          16.1.2 Power management parameter definitions
          16.1.3 Power management state machine specifications
               16.1.3.1 ONU state machine
               16.1.3.2 OLT CT state machine
          16.1.4 Management transactions in the LowPower state
          16.1.5 Power saving by channel selection
     16.2 PtP WDM power management
          16.2.1 Line rate adjustment sequences
          16.2.2 Parameters
17 TWDM channel management
     17.1 Profile announcement
          17.1.1 NG-PON2 system and channel descriptors
          17.1.2 Profile parameter learning by ONU
     17.2 ONU calibration
          17.2.1 In-service downstream wavelength channel calibration
          17.2.2 In-service upstream wavelength channel calibration
     17.3 ONU wavelength channel handover
          17.3.1 Causal sequence of ONU handover events
          17.3.2 ONU wavelength channel handover failure conditions
          17.3.3 OLT wavelength channel handover state machine
               17.3.3.1 States, timers, inputs and outputs
               17.3.3.2 OLT tuning state diagram
               17.3.3.3 OLT state transition table
     17.4 ONU wavelength channel locking
18 TWDM system protection
     18.1 OLT CT coordination in 1:1 Type B protection
     18.2 OLT CT Type B protection state machine
          18.2.1 States
          18.2.2 Timers
          18.2.3 Events
          18.2.4 State transition diagram
          18.2.5 State transition table
     18.3 Simplified state transition diagram
19 Rogue behaviour and its mitigation
     19.1 Rogue ONU behaviour model in TWDM-PON
     19.2 Rogue ONU behaviour model for PtP WDM
     19.3 Behaviour model when coexisting with ITU-T G.984 and ITU-T G.987 ONUs
          19.3.1 Silent start at the ONU
          19.3.2 Silent start at the channel termination (OLT port)
          19.3.3 Channel termination (OLT port) detection of rogue devices
     19.4 Protection from noise and alien ONUs
     19.5 Troublesome ONU presence detection enabled through idle window
Annex A  Hybrid error control (HEC) decoding and scrambler sequence codes
     A.1 HEC decoding
     A.2  Scrambler sequence
Annex B  Forward error correction using shortened Reed-Solomon codes
Annex C  Secure mutual authentication via OMCI
Annex D  Secure mutual authentication using IEEE 802.1X
Annex E  Auxiliary management and control channel
Annex F  Tuning sequences
     F.1 Tuning sequences
          F.1.1 Normal tuning sequences and timer operation
          F.1.2 ROLLBACK sequence and timer operation
          F.1.3 NACK sequences and state transition
     F.2 Definition of TC layer tuning time
Annex G  Transcoded framing with FEC and OAM for PtP WDM AMCC TC
     G.1 Services with 8B/10B line code
          G.1.1 32B/34B transcoding
          G.1.2 32B/34B code framing with FEC and OAM
     G.2 Services with 64B/66B line code
Annex H  Wavelength channel bonding
     H.1 Bonded ONU activation
Annex I
Annex J  Contention-based PON operation
     J.1 Contention-based allocations
     J.2 Contention-based functions overview
          J.2.1 ONU activation
          J.2.2 Wavelength protection
          J.2.3 Idle ONUsupport
          J.2.4 Watchful sleep support
     J.3 Contention-based functions associated with explicitly assigned Alloc-IDs
     J.4 PLOAM message modifications
          J.4.1 Broadcast Assign_Alloc-ID PLOAM message
          J.4.2 Extended Acknowledgment PLOAM message
          J.4.3 Extended Tuning_Response PLOAM message
Annex K  Collision resolution for contention-based allocations
     K.1 Collision resolution for contention-based allocation
     K.2 Set-splitting collision resolution protocol
     K.3 Reporting collision outcome
     K.4 ONU support of the Set-splitting collision resolution protocol
     K.5 New PLOAM message
Appendix I  Downstream line data pattern conditioning
Appendix II  Time of day derivation and error analysis
Appendix III  Burst profiles
Appendix IV  Golden vectors
     IV.1 10G downstream and upstream FEC codeword
     IV.2  10G upstream FEC short codeword
     IV.3 2.5G downstream and upstream FEC codeword
     IV.4 2.5G downstream FEC short codeword
     IV.5 2.5G upstream FEC short codeword
     IV.6 Downstream AES-128 encryption
     IV.7 Upstream AES-128 encryption
     IV.8 Key derivation encryption
     IV.9 Downstream PLOAM message integrity check
     IV.10 Upstream PLOAM message integrity check
     IV.11 Upstream key reporting
     IV.12 Downstream OMCI message integrity check
Appendix V  Protection examples
Appendix VI  ICTP: Inter-channel-termination protocol
     VI.1 ICTP use cases
     VI.2 ICTP primitives description
Appendix VII  ONU equalization delay coordination across TWDM channels
     VII.1 Re-ranging
     VII.2 Consistent equalization delay method
     VII.3 EqD pre-configuration
Appendix VIII  PON-ID and NG-PON2 system identifier examples
Appendix IX  Cooperative DBA by client systems for low-latency services
     IX.1 PON application to low-latency services and its challenge
     IX.2 Cooperative DBA by client systems
     IX.3 Use case – mobile fronthaul
     IX.4 Reference Point
Appendix X  Combining OLT CTs with multiple ODN optical path loss classes  in the same NG-PON2 system
     X.1 Motivation for combining multiple optical path loss classes in an NG-PON2 system
     X.2 Best practice use case description
          X.2.1 Typical NG-PON2 deployment with a single class of ODN loss optics
          X.2.2 NG-PON2 deployment with a multiple ODN optical path loss class modules
               X.2.3 TC layer considerations
Bibliography
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