text: **Prerequisites**
  The following prerequisites must be met for all RDMA-based connections between nodes: 
  
  (cid:2) Installation of the node hardware is complete. 
  
  (cid:2) A 25 Gbps Ethernet adapter is installed on each node. 
  
  (cid:2) Ethernet cables between each node are connected correctly. 
  
  (cid:2) Protocols on the source and destination adapters are the same. 
  
  (cid:2) Local and remote IP addresses can be reached. 
  
  (cid:2) Each IP address is unique. 
  
  (cid:2) The negotiated speeds on the local and remote adapters are the same. 
  
  (cid:2) The local and remote port virtual LAN identifiers are the same. 
  
  (cid:2) A minimum of two dedicated ports are required for node-to-node RDMA communications 
  to ensure best performance and reliability. These ports must be configured for inter-node 
  traffic only and cannot be used for host attachment, virtualization of Ethernet-attached 
  external storage, or IP replication traffic. 
  
  (cid:2) A maximum of four ports per node are allowed for node-to-node RDMA connections. 
  
  Configure a local port mask that limits node-to-node connections to maximum of four ports 
  per node. For more information, see this IBM Knowledge Center web page. 