This step requires a default service class, for which messages of unknown priority type can be assigned.

此步骤需要一个缺省服务分类，用于分配未知优先级类型的消息。

youdao

This step requires a default service class, for which messages of unknown priority type can be assigned.

此步骤需要一个缺省服务分类，用于分配未知优先级类型的消息。

youdao