Hi all, I'm using qperf to compare TCP & RDMARC performance. qperf report that it failed to modify the QP to RTR status. Does anyone know how to solve the problem? Host A:nstcloudcc1 configuration: nstcc1@nstcloudcc1:tmp$ ib2netdev mlx5_0 port 1 ==> ens261f0 (Up) 173.168.100.103 mlx5_1 port 1 ==> ens261f1 (Down) nstcc1@nstcloudcc1:tmp$ Host B:rdmarhel0 configuration: [rdma@rdmarhel0 tmp]$ ib2netdev mlx5_0 port 1 ==> ens801f0 (Up) 173.168.100.101 mlx5_1 port 1 ==> ens801f1 (Up) 192.168.100.101 [rdma@rdmarhel0 tmp]$ Run below command on host A as server: nstcc1@nstcloudcc1:tmp$ qperf Run below command on host B as client: [rdma@rdmarhel0 tmp]$ qperf 173.168.100.103 rc_bw rc_bw: failed to modify QP to RTR: Invalid argument The log shows as above on cient that it failed to modify QP to RTR --Thanks Changcheng