Table of Contents - G.9804.1 (2019) Amd. 3 (05/2025) -

1	Scope
2	References
3	Definitions
	3.1	Terms defined elsewhere
	3.2	Terms defined in this Recommendation
4	Abbreviations and acronyms
5	Conventions
	5.1	Optical access concepts
	5.2	Higher speed PON system reference points
	5.3	Optical power and loss parameters
	5.4	Dynamic range, sensitivity, and overload
	5.5	Sensitivity and overload in the presence of FEC
	5.6	Reach and distance
	5.7	Use of the term PON
	5.8	Use of the term ODN
	5.9	Use of the terms ONU and ONT
	5.10	Use of the terms T-CONT and Alloc-ID
	5.11	Use of the terms bandwidth assignment and bandwidth allocation
	5.12	Use of the terms band and range
	5.13	Transmitter enable control and associated transient times
6	Architecture of the HSP
	6.1	Network architecture
	6.2	System overview
	6.3	Network reference configurations
7	Migration scenarios
	7.1	Coexistence
	7.2	Migration path options
	7.3	Migration to 50G TDM PON
8	Service requirements
	8.1	Service specific requirements
	8.2	User node interfaces (UNIs)
	8.3	Service node interfaces (SNIs)
	8.4	Access node interfaces (ANIs)
	8.5	Latency
	8.6	Synchronization features and quality
	8.7	System flexibility
9	Physical layer requirements
	9.1	System capacity
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	9.2	Fibre characteristics
	9.3	Optical loss budget
	9.4	Split ratio
	9.5	Fibre distance
	9.6	Optical spectrum issues and availability
10	System level requirements
	10.1	Authentication/encryption
	10.2	Dynamic bandwidth assignment (DBA)
	10.3	Dual-rate support
	10.4	Colourless ONUs of 50G TWDM PON and PtP WDM PON
	10.5	Spectral flexibility of 50G TWDM PON and PtP WDM PON
	10.6	Rogue and alien ONU/OLT detection and mitigation
	10.7	Reach extender requirements
	10.8	Power reduction
	10.9	PON supervision and OAM functions
	10.10	Provisioning and management
	10.11	OLT and ONU environmental and physical requirements
	10.12	Eye safety
	10.13	Interoperability
	10.14	Transport of wireless fronthaul links over the access system
	10.15	Slicing requirement
	10.16	Optional Flexible FEC in upstream
11	Resilience and protection on ODN
	11.1	Type B protection
	11.2	Type C protection
	11.3	Type W protection (for 50G TWDM PON and PTP WDM PON)
	11.4	Protection category
Appendix I – OLT resilience configuration of 50G TWDM PON
	I.1	OLT resilience configuration
Bibliography