Recommendation ITU-T G.709.1 (03/2024) Flexible OTN common elements
Summary
History
FOREWORD
Table of Contents
1 Scope
2 References
3 Definitions
     3.1 Terms defined elsewhere
     3.2 Terms defined in this Recommendation
4 Abbreviations and acronyms
5 Conventions
6 Introduction and applications
     6.1 Short-reach FlexO interfaces
     6.2 Long-reach FlexO interfaces
7 Structure and processes
     7.1 Basic signal structure
     7.2 Processing and information flow
8 FlexO frame and maintenance
     8.1 Frame structure
     8.2 Multi-frame structure
     8.3 Bit rates and frame periods
     8.4 FlexO-x(e) frame structure
     8.5 FlexO maintenance
9 Overhead
     9.1 Alignment mechanism
     9.2 Basic overhead (BOH) description
          9.2.1 Multi-frame alignment signal (MFAS)
          9.2.2 Group management overhead
               9.2.2.1 Group identification (GID)
               9.2.2.2 FlexO instance identification (IID)
               9.2.2.3 FlexO map (MAP)
          9.2.3 Status (STAT)
               9.2.3.1 Remote fault (RF)
               9.2.3.2 Reserved (RES)
               9.2.3.3 Maintenance (MNT)
          9.2.4 Payload overhead
               9.2.4.1 OTUC availability (AVAIL)
               9.2.4.2 Payload type (PT)
               9.2.4.3 Client specific overhead allocation
          9.2.5 Cyclic redundancy check (CRC)
          9.2.6 FlexO management communications channel (FCC1)
          9.2.7 FlexO reserved overhead (RES)
          9.2.8 OTN synchronization message channel (OSMC)
               9.2.8.1 Generation of event message timestamp
     9.3 Extended overhead (EOH) description
          9.3.1 FlexOfec overhead
               9.3.1.1 Staircase FEC block alignment (FBA) field
          9.3.2 FlexOsec overhead
               9.3.2.1 Authentication tag (AT)
               9.3.2.2 Frame number (FN)
               9.3.2.3 Key index (KI)
               9.3.2.4 Cipher suite type (CST)
               9.3.2.5 Key exchange communication channel (KCC)
               9.3.2.6 Reserved (RES)
          9.3.3 FlexO regeneration overhead (regen)
               9.3.3.1 Regen multi-frame alignment signal (RMFAS)
               9.3.3.2 Regen status (RSTAT)
                    9.3.3.2.1 Remote fault indication (RF)
                    9.3.3.2.2 Degrade indication (LD/RD)
                    9.3.3.2.3 Reserved (RES)
               9.3.3.3 Regen trail trace identifier (RTTI)
               9.3.3.4 FlexO regen communication channel (FCC0)
10 FlexO mapping procedures
     10.1 BMP mapping of OTUCn client into FlexO-n
          10.1.1 Distributing OTUCn and combining OTUC instances
          10.1.2 FlexO multi-frame payload
          10.1.3 Mapping of OTUC into FlexO multi-frame payload
               10.1.3.1 Mapping of OTUC into FlexO frame
          10.1.4 Client mapping specific overhead
     10.2 GMP mapping of Ethernet clients into FlexO-ne
          10.2.1 FlexO frame and 4-frame multi-frame payload structure
          10.2.2 Ethernet client
          10.2.3 Client mapping specific overhead
               10.2.3.1 FlexO multiplex structure identifier (MSI)
               10.2.3.2 FlexO justification overhead (JC)
               10.2.3.3 Client status (CSTAT)
                    10.2.3.3.1 Client signal fail (CSF)
                    10.2.3.3.2 Reserved (RES)
                    10.2.3.3.3 Maintenance (MNT)
                    10.2.3.3.4 Client degrade indication (LD/RD)
          10.2.4 Mapping of y00GBASE-R client into y FlexO instances of a FlexO-ne
     10.3 GMP mapping of OTUCn clients into FlexO-n
          10.3.1 Distributing OTUCni and combining OTUC instances
          10.3.2 FlexO frame and 4-frame multi-frame payload structure
          10.3.3 Client mapping specific overhead
               10.3.3.1 FlexO multiplex structure identifier (MSI)
               10.3.3.2 FlexO justification overhead
          10.3.4 Mapping of OTUCni into ni FlexO instances of a FlexO-n
               10.3.4.1 Mapping OTUC into FlexO instance payload
     10.4 FlexO-n group alignment and deskewing
          10.4.1 Alignment and deskewing of OTUCn clients
     10.5 FlexO payload PRBS test pattern
          10.5.1 Client mapping specific overhead
Annex A  FlexOsec encryption and authentication
     A.1 GCM-AES-256 frame payload encryption
          A.1.1 GCM-AES-256 confidentiality (encryption)
          A.1.2 GCM-AES-256 integrity (authentication)
          A.1.3 IV construction
          A.1.4 GCM-AES-256 algorithms
Annex B  Applying generic mapping procedure principles in a FlexO-n(e)
     B.1 Applying GMP in a FlexO-n(e)
          B.1.1 Mapping granularity
          B.1.2 FlexO Cm(t) encoding and decoding
               B.1.2.1 FlexO Cm(t) encoding and decoding for FlexO-ne and FlexO-n
          B.1.3 FlexO (CnD(t) encoding and decoding
               B.1.3.1 (CnD(t) encoding and decoding for FlexO-n(e)
Annex C  Transporting Ethernet client and Regen local degrade and remote degrade
     C.1 Ethernet client CSTAT LD/RD
     C.2 Ethernet client CSTAT and Regen RSTAT LD/RD
Appendix I  Example short-reach applications
Appendix II  Example long-reach applications
Bibliography