MySQL 9.0 Release Notes
        
      Even before design of NDBCLUSTER
      began in 1996, it was evident that one of the major problems to be
      encountered in building parallel databases would be communication
      between the nodes in the network. For this reason,
      NDBCLUSTER was designed from the very
      beginning to permit the use of a number of different data
      transport mechanisms, or transporters.
    
      NDB Cluster supports three of these (see
      Section 25.2.1, “NDB Cluster Core Concepts”). A fourth transporter,
      Scalable Coherent Interface (SCI), was also supported in very old
      versions of NDB. This required specialized
      hardware, software, and MySQL binaries that are no longer
      available.