Recommendation ITU-T G.7703 describes the reference architecture and requirements for the automatically switched optical network (ASON) as applicable to connection-oriented circuit or packet transport networks. This reference architecture is described in terms of the key functional components and the interactions between them. This amendment aligns with G.7701 (2022), which specifies common control aspects for both ASON and software defined networking (SDN) architecture. This amendment refers to G.7701 common clauses.