A common WDM service can be converted into an ODUk SNCP service. However, an ODUk SNCP service will be interrupted when it is converted into a common WDM service.

The statement is correct. In Huawei Optical Transport Network (OTN) systems, it is possible to modify the protection level of an existing service. When upgrading a common (unprotected) WDM service to an ODUk Sub-Network Connection Protection (SNCP) service, the operation is typically designed to be non-service-affecting or "hitless." This is because the existing working path remains active while a new, separate protection path is provisioned and added to the service configuration. However, when converting an existing ODUk SNCP service back to a common (unprotected) WDM service, a brief service interruption is expected. This interruption occurs because the system must reconfigure the service's cross-connections. It involves tearing down the protection path and changing the service logic from a 1+1 protection selection mechanism to a simple point-to-point path, which momentarily disrupts the flow of traffic.

The "False" option is incorrect because it would imply that either the conversion is not possible or that converting from ODUk SNCP to a common service is also hitless. Official documentation and standard operational procedures for Huawei WDM/OTN equipment confirm that downgrading the protection level from SNCP to unprotected is a service-affecting operation.

1. Huawei HCIP-Transmission V2.0 Training Material: In the module covering OTN service provisioning and management, the process of modifying service protection levels is detailed. It explicitly states that changing the protection type from ODUk SNCP to "no protection" will cause a service interruption, whereas changing from "no protection" to ODUk SNCP is a non-service-affecting operation. (Refer to sections on "Service Configuration and Management" and "OTN Protection Schemes").

2. Huawei OptiX OSN 8800 Product Documentation - Service Management Guide: The guide for managing optical services on platforms like the OptiX OSN 8800 contains tables and procedural notes on modifying service attributes. In the section "Modifying WDM Service Protection," it is specified that changing the "Protection Subtype" from SNCP to "Unprotected" is a service-affecting procedure, and a warning is typically provided in the Network Management System (NMS) before the operation is confirmed. Conversely, the change from "Unprotected" to "SNCP" is listed as non-service-affecting. (Refer to chapters on ODUk service provisioning and protection configuration).