China Telecom China Telecom China Telecom China Telecom With the rapid development of large language models, many emerging AI scenarios require tunnel-based lossless transmission of RDMA packets in WAN. To fulfill this requirement, WAN should support the real- time notification of network conditions to ensure high throughput, low latency, and zero packet loss data transmission. The current reactive notification solution is limited by responsiveness, coverage, and operational overhead. Therefore, we need to establish a faster and proactive notification mechanism to implement more responsive Traffic Engineering and Load Balancing. This draft first describes typical scenarios for tunnel-based RDMA lossless transmission in WAN, then specifies the fast notification framework for implementing key TE areas (congestion control, protection, and load balance), and finally analyses the protocol implementation for fast notification.