On 13 August 2026, design guidelines for all-photonic networks approved as an international standard by the ITU-T were published. The guidelines were led by 7 Japanese companies, including NTT and KDDI. A common framework based on wide-area interconnection is expected to be adopted going forward.
The design guidelines approved as ITU-T Recommendation Y.3335 define the path configuration and technical requirements for optical networks that combine low latency with low power consumption. They are expected to make it easier to implement APN services spanning multiple operators under a common framework.
The guidelines were developed under the leadership of 7 Japanese companies: KDDI, NTT, 1FINITY, NEC, Rakuten Mobile, Oki Electric Industry and Sumitomo Electric Industries. The international standardization effort is also linked to the Beyond 5G Promotion Strategy and is positioned as an initiative aimed at achieving interoperability in the context of the I/OWN Global Forum.
The ITU-T is scheduled to develop detailed functional architecture recommendations based on these guidelines by October 2028. The guidelines are expected to be referenced by operators and equipment vendors in Japan and overseas when preparing procurement specifications and verifying designs. As adoption progresses, high-speed, energy-efficient communications services between geographically dispersed sites are expected to see wider use.
For companies, the guidelines are attracting attention because they provide a standards-based foundation for considering and evaluating interconnection requirements, with data exchange across wide areas and distributed processing of AI workloads in mind. Future implementation studies are expected to reduce interconnection barriers and shorten development timelines.