Recommendation ITU-T G.7714.1/Y.1705.1 Amendment 1 (05/2021) Protocol for automatic discovery in transport networks Summary 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 Discovery methodology 5.1 CP-CP connectivity relationships determination 6 Mechanisms for layer adjacency discovery 6.1 Layer adjacency discovery of transport entities 7 Attributes used in layer adjacency 8 Layer adjacency based on trail trace string 8.1 Discovery message formats 8.1.1 TCP name format 8.1.2 DA DCN address format 8.1.3 DA DCN name format 8.1.4 ETH MAC address format 9 Layer adjacency based on embedded control channel messages 9.1 LAPD-based mechanism 9.2 PPP-based mechanism 9.3 Interoperable solution when using ECC based mechanism 9.4 PPP-based support in OTN ECC 9.4.1 LLDP/PPP 9.4.2 LLDP/MAC/PPP 10 Layer adjacency based on packet OAM frames 10.1 Ethernet link discovery mechanism 10.2 MPLS-TP transport entity discovery mechanism 11 Procedures 12 Discovery response message 12.1 Miswiring detection 12.2 Misconnection detection Appendix I Implementation example of discovery process I.1 Layer adjacency discovery information flow Appendix II Miswiring detection II.1 Auto-discovery procedures II.2 Example: Interaction between two DAs using different DM formats Appendix III Example of discovery response message using a generalized multi-protocol label signalling-based mechanism Appendix IV Layer adjacency discovery implementation examples Appendix V In-band message encoding example Appendix VI Usage of the different discovery mechanisms VI.1 Introduction VI.2 Categories of Type 1 layer adjacency discovery use cases VI.3 Use cases and scenarios VI.3.1 All NEs are auto-discovery capable (ubiquitous deployment) VI.3.2 All NEs are not auto-discovery capable VI.3.2.1 Auto-discovery between LAD-capable NEs VI.3.2.2 Auto-discovery between a LAD-capable NE and a non-LAD-capable NE VI.4 Guidelines for mechanisms and procedures VI.4.1 ECC-based LAD VI.4.1.1 DCN deployment scenarios impacting the availability of DCCs VI.4.2 Trail-trace-based LAD VI.4.2.1 Pre-service and out-of-service cases VI.4.2.2 In-service cases VI.4.3 Inter-carrier, user-provider implications Bibliography <\pre>