Development of technology to achieve high reliability and maintenance operationNext generation Ethernet technologyNTT Access Network Service Systems Laboratories

In providing next-generation Ethernet services, we have developed high-speed switching and fault detection technologies in redundant configurations using Ethernet ring protection, Ethernet OAM, and access redundancy technologies, as well as network operation technologies that enable centralized end-to-end management, testing, and monitoring in conjunction with the above three technologies, thereby realizing high reliability and maintainability of this service. (Results provided, projects implemented)

• Ethernet ring protection: Autonomous recovery when there is a failure in a ring network. Switching method that prevents loop failures increases reliability
• Ethernet OAM: Provides constant monitoring, fault isolation, and performance measurement for each VLAN, improving maintainability
• Access redundancy: Improves reliability by duplicating lines in the access section and switching at high speed in case of failure.
• Network operations: Centralized end-to-end management, testing, and monitoring of networks utilizing the above three technologies

Ethernet ring protection is a technology that protects communications by switching routes in the event of a failure in a ring network without silent failures or loops.
Ethernet OAM is a technology that sends and receives control frames within the network to (1) detect faults, (2) identify fault locations, (3) check the continuity of the pass, and (4) measure delay performance to improve network maintainability.
Access redundancy is a technology that improves network reliability by duplicating the access lines from the customer location to the L2 switch. In the event of a failure, the customer's communication path can be quickly switched to another access line.
We have developed the above three network technologies and network operation technologies that enable them to operate, for which we have achieved high reliability and maintainability.

Ethernet OAM
Operation, Administration and Maintenance

1. Ethernet network maintenance and management functions
2. Standardized by the International Telecommunication Union Telecommunication Standardization Sector (ITU-T) as International Recommendation Y.1731
3. Standardized by IEEE802 committee as IEEE802.1ag

Ring network
A network of L2 switches connected in a ring

Loop fault
In a ring network, this is an event where the same frame is sent in a loop, wasting network resources and causing the system to go down.

NTT Access Network Service Systems Laboratories - Optical Access Infrastructure Project