This diagram is intended to illustrate the relationship between the specification and software aspects of CGNS. On the left are four boxes, with the following labels:

On the right there are also four boxes, with the following labels:

The "SIDS" box on the left points to the "End User Application" box on the right. The "MLL tree interface" box on the left points to the "MLL (Trees)" box on the right. The "SLL tree interface" and "SLL mapping to HDF5" boxes on the left both point to both the "SLL (Nodes)" box on the right.