1     Scope 
 2     References
 3     Definitions    
 4     Abbreviations 
 5     Architecture of the optical access network     
 6     Services   
 7     User network interface and service node interface      
 8     Optical network requirements  
        8.1     Layered structure of optical network    
        8.2     Physical medium dependent layer requirements for the GPON 
        8.3     Interaction between GPON PMD layer and TC layer   
Appendix I – Allocation of the physical layer overhead time    
Appendix II – Description and examples of power levelling mechanism    
       II.1     Introduction       
       II.2     ONU levels        
       II.3     Thresholds at OLT        
       II.4     Power detection